Analysis/include/Luau/AnyTypeSummary.h

@@ -0,0 +1,148 @@
+// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
+#pragma once
+
+#include "Luau/AstQuery.h"
+#include "Luau/Config.h"
+#include "Luau/ModuleResolver.h"
+#include "Luau/Scope.h"
+#include "Luau/Variant.h"
+#include "Luau/Normalize.h"
+#include "Luau/TypePack.h"
+#include "Luau/TypeArena.h"
+
+#include <mutex>
+#include <string>
+#include <vector>
+#include <optional>
+
+namespace Luau
+{
+
+class AstStat;
+class ParseError;
+struct TypeError;
+struct LintWarning;
+struct GlobalTypes;
+struct ModuleResolver;
+struct ParseResult;
+struct DcrLogger;
+
+struct TelemetryTypePair
+{
+    std::string annotatedType;
+    std::string inferredType;
+};
+
+struct AnyTypeSummary
+{
+    TypeArena arena;
+
+    AstStatBlock* rootSrc = nullptr;
+    DenseHashSet<TypeId> seenTypeFamilyInstances{nullptr};
+
+    int recursionCount = 0;
+
+    std::string root;
+    int strictCount = 0;
+
+    DenseHashMap<const void*, bool> seen{nullptr};
+
+    AnyTypeSummary();
+
+    void traverse(const Module* module, AstStat* src, NotNull<BuiltinTypes> builtinTypes);
+
+    std::pair<bool, TypeId> checkForAnyCast(const Scope* scope, AstExprTypeAssertion* expr);
+
+    bool containsAny(TypePackId typ);
+    bool containsAny(TypeId typ);
+
+    bool isAnyCast(const Scope* scope, AstExpr* expr, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    bool isAnyCall(const Scope* scope, AstExpr* expr, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+
+    bool hasVariadicAnys(const Scope* scope, AstExprFunction* expr, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    bool hasArgAnys(const Scope* scope, AstExprFunction* expr, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    bool hasAnyReturns(const Scope* scope, AstExprFunction* expr, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+
+    TypeId checkForFamilyInhabitance(const TypeId instance, Location location);
+    TypeId lookupType(const AstExpr* expr, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    TypePackId reconstructTypePack(const AstArray<AstExpr*> exprs, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+
+    DenseHashSet<TypeId> seenTypeFunctionInstances{nullptr};
+    TypeId lookupAnnotation(AstType* annotation, const Module* module, NotNull<BuiltinTypes> builtintypes);
+    std::optional<TypePackId> lookupPackAnnotation(AstTypePack* annotation, const Module* module);
+    TypeId checkForTypeFunctionInhabitance(const TypeId instance, const Location location);
+
+    enum Pattern : uint64_t
+    {
+        Casts,
+        FuncArg,
+        FuncRet,
+        FuncApp,
+        VarAnnot,
+        VarAny,
+        TableProp,
+        Alias,
+        Assign,
+        TypePk
+    };
+
+    struct TypeInfo
+    {
+        Pattern code;
+        std::string node;
+        TelemetryTypePair type;
+
+        explicit TypeInfo(Pattern code, std::string node, TelemetryTypePair type);
+    };
+
+    struct FindReturnAncestry final : public AstVisitor
+    {
+        AstNode* currNode{nullptr};
+        AstNode* stat{nullptr};
+        Position rootEnd;
+        bool found = false;
+
+        explicit FindReturnAncestry(AstNode* stat, Position rootEnd);
+
+        bool visit(AstType* node) override;
+        bool visit(AstNode* node) override;
+        bool visit(AstStatFunction* node) override;
+        bool visit(AstStatLocalFunction* node) override;
+    };
+
+    std::vector<TypeInfo> typeInfo;
+
+    /**
+     * Fabricates a scope that is a child of another scope.
+     * @param node the lexical node that the scope belongs to.
+     * @param parent the parent scope of the new scope. Must not be null.
+     */
+    const Scope* childScope(const AstNode* node, const Scope* parent);
+
+    std::optional<AstExpr*> matchRequire(const AstExprCall& call);
+    AstNode* getNode(AstStatBlock* root, AstNode* node);
+    const Scope* findInnerMostScope(const Location location, const Module* module);
+    const AstNode* findAstAncestryAtLocation(const AstStatBlock* root, AstNode* node);
+
+    void visit(const Scope* scope, AstStat* stat, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    void visit(const Scope* scope, AstStatBlock* block, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    void visit(const Scope* scope, AstStatIf* ifStatement, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    void visit(const Scope* scope, AstStatWhile* while_, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    void visit(const Scope* scope, AstStatRepeat* repeat, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    void visit(const Scope* scope, AstStatReturn* ret, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    void visit(const Scope* scope, AstStatLocal* local, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    void visit(const Scope* scope, AstStatFor* for_, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    void visit(const Scope* scope, AstStatForIn* forIn, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    void visit(const Scope* scope, AstStatAssign* assign, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    void visit(const Scope* scope, AstStatCompoundAssign* assign, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    void visit(const Scope* scope, AstStatFunction* function, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    void visit(const Scope* scope, AstStatLocalFunction* function, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    void visit(const Scope* scope, AstStatTypeAlias* alias, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    void visit(const Scope* scope, AstStatExpr* expr, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    void visit(const Scope* scope, AstStatDeclareGlobal* declareGlobal, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    void visit(const Scope* scope, AstStatDeclareClass* declareClass, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    void visit(const Scope* scope, AstStatDeclareFunction* declareFunction, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+    void visit(const Scope* scope, AstStatError* error, const Module* module, NotNull<BuiltinTypes> builtinTypes);
+};
+
+} // namespace Luau

Analysis/include/Luau/AutocompleteTypes.h

@@ -57,7 +57,7 @@ struct AutocompleteEntry
     // Set if this suggestion matches the type expected in the context
     TypeCorrectKind typeCorrect = TypeCorrectKind::None;
 
-    std::optional<const ExternType*> containingExternType = std::nullopt;
+    std::optional<const ClassType*> containingClass = std::nullopt;
     std::optional<const Property*> prop = std::nullopt;
     std::optional<std::string> documentationSymbol = std::nullopt;
     Tags tags;
@@ -85,7 +85,7 @@ struct AutocompleteResult
 };
 
 using StringCompletionCallback =
-    std::function<std::optional<AutocompleteEntryMap>(std::string tag, std::optional<const ExternType*> ctx, std::optional<std::string> contents)>;
+    std::function<std::optional<AutocompleteEntryMap>(std::string tag, std::optional<const ClassType*> ctx, std::optional<std::string> contents)>;
 
 constexpr char kGeneratedAnonymousFunctionEntryName[] = "function (anonymous autofilled)";
 

Analysis/include/Luau/Constraint.h

@@ -50,7 +50,6 @@ struct GeneralizationConstraint
     TypeId sourceType;
 
     std::vector<TypeId> interiorTypes;
-    bool hasDeprecatedAttribute = false;
 };
 
 // variables ~ iterate iterator

Analysis/include/Luau/ConstraintGenerator.h

@@ -3,7 +3,6 @@
 
 #include "Luau/Ast.h"
 #include "Luau/Constraint.h"
-#include "Luau/ConstraintSet.h"
 #include "Luau/ControlFlow.h"
 #include "Luau/DataFlowGraph.h"
 #include "Luau/EqSatSimplification.h"
@@ -12,14 +11,15 @@
 #include "Luau/ModuleResolver.h"
 #include "Luau/Normalize.h"
 #include "Luau/NotNull.h"
-#include "Luau/Polarity.h"
 #include "Luau/Refinement.h"
 #include "Luau/Symbol.h"
 #include "Luau/TypeFwd.h"
 #include "Luau/TypeUtils.h"
+#include "Luau/Variant.h"
 
 #include <memory>
 #include <vector>
+#include <unordered_map>
 
 namespace Luau
 {
@@ -92,8 +92,9 @@ struct ConstraintGenerator
     // Constraints that go straight to the solver.
     std::vector<ConstraintPtr> constraints;
 
-    // The set of all free types introduced during constraint generation.
+    // Constraints that do not go to the solver right away.  Other constraints
-    DenseHashSet<TypeId> freeTypes{nullptr};
+    // will enqueue them during solving.
+    std::vector<ConstraintPtr> unqueuedConstraints;
 
     // Map a function's signature scope back to its signature type.
     DenseHashMap<Scope*, TypeId> scopeToFunction{nullptr};
@@ -131,8 +132,6 @@ struct ConstraintGenerator
 
     DenseHashMap<TypeId, TypeIds> localTypes{nullptr};
 
-    DenseHashMap<AstExpr*, Inference> inferredExprCache{nullptr};
-
     DcrLogger* logger;
 
     ConstraintGenerator(
@@ -151,9 +150,6 @@ struct ConstraintGenerator
         std::vector<RequireCycle> requireCycles
     );
 
-    ConstraintSet run(AstStatBlock* block);
-    ConstraintSet runOnFragment(const ScopePtr& resumeScope, AstStatBlock* block);
-
     /**
      * The entry point to the ConstraintGenerator. This will construct a set
      * of scopes, constraints, and free types that can be solved later.
@@ -164,26 +160,19 @@ struct ConstraintGenerator
     void visitFragmentRoot(const ScopePtr& resumeScope, AstStatBlock* block);
 
 private:
-    struct InteriorFreeTypes
+    std::vector<std::vector<TypeId>> interiorTypes;
-    {
-        std::vector<TypeId> types;
-        std::vector<TypePackId> typePacks;
-    };
-
-    std::vector<std::vector<TypeId>> DEPRECATED_interiorTypes;
-    std::vector<InteriorFreeTypes> interiorFreeTypes;
 
     /**
      * Fabricates a new free type belonging to a given scope.
      * @param scope the scope the free type belongs to.
      */
-    TypeId freshType(const ScopePtr& scope, Polarity polarity = Polarity::Unknown);
+    TypeId freshType(const ScopePtr& scope);
 
     /**
      * Fabricates a new free type pack belonging to a given scope.
      * @param scope the scope the free type pack belongs to.
      */
-    TypePackId freshTypePack(const ScopePtr& scope, Polarity polarity = Polarity::Unknown);
+    TypePackId freshTypePack(const ScopePtr& scope);
 
     /**
      * Allocate a new TypePack with the given head and tail.
@@ -272,7 +261,7 @@ private:
     ControlFlow visit(const ScopePtr& scope, AstStatTypeAlias* alias);
     ControlFlow visit(const ScopePtr& scope, AstStatTypeFunction* function);
     ControlFlow visit(const ScopePtr& scope, AstStatDeclareGlobal* declareGlobal);
-    ControlFlow visit(const ScopePtr& scope, AstStatDeclareExternType* declareExternType);
+    ControlFlow visit(const ScopePtr& scope, AstStatDeclareClass* declareClass);
     ControlFlow visit(const ScopePtr& scope, AstStatDeclareFunction* declareFunction);
     ControlFlow visit(const ScopePtr& scope, AstStatError* error);
 
@@ -304,7 +293,7 @@ private:
     );
 
     Inference check(const ScopePtr& scope, AstExprConstantString* string, std::optional<TypeId> expectedType, bool forceSingleton);
-    Inference check(const ScopePtr& scope, AstExprConstantBool* boolExpr, std::optional<TypeId> expectedType, bool forceSingleton);
+    Inference check(const ScopePtr& scope, AstExprConstantBool* bool_, std::optional<TypeId> expectedType, bool forceSingleton);
     Inference check(const ScopePtr& scope, AstExprLocal* local);
     Inference check(const ScopePtr& scope, AstExprGlobal* global);
     Inference checkIndexName(const ScopePtr& scope, const RefinementKey* key, AstExpr* indexee, const std::string& index, Location indexLocation);
@@ -380,11 +369,6 @@ private:
      **/
     TypeId resolveType(const ScopePtr& scope, AstType* ty, bool inTypeArguments, bool replaceErrorWithFresh = false);
 
-    // resolveType() is recursive, but we only want to invoke
-    // inferGenericPolarities() once at the very end.  We thus isolate the
-    // recursive part of the algorithm to this internal helper.
-    TypeId resolveType_(const ScopePtr& scope, AstType* ty, bool inTypeArguments, bool replaceErrorWithFresh = false);
-
     /**
      * Resolves a type pack from its AST annotation.
      * @param scope the scope that the type annotation appears within.
@@ -394,9 +378,6 @@ private:
      **/
     TypePackId resolveTypePack(const ScopePtr& scope, AstTypePack* tp, bool inTypeArguments, bool replaceErrorWithFresh = false);
 
-    // Inner hepler for resolveTypePack
-    TypePackId resolveTypePack_(const ScopePtr& scope, AstTypePack* tp, bool inTypeArguments, bool replaceErrorWithFresh = false);
-
     /**
      * Resolves a type pack from its AST annotation.
      * @param scope the scope that the type annotation appears within.
@@ -435,7 +416,7 @@ private:
      **/
     std::vector<std::pair<Name, GenericTypePackDefinition>> createGenericPacks(
         const ScopePtr& scope,
-        AstArray<AstGenericTypePack*> generics,
+        AstArray<AstGenericTypePack*> packs,
         bool useCache = false,
         bool addTypes = true
     );
@@ -484,4 +465,9 @@ private:
     TypeId simplifyUnion(const ScopePtr& scope, Location location, TypeId left, TypeId right);
 };
 
+/** Borrow a vector of pointers from a vector of owning pointers to constraints.
+ */
+std::vector<NotNull<Constraint>> borrowConstraints(const std::vector<ConstraintPtr>& constraints);
+
+
 } // namespace Luau

Analysis/include/Luau/ConstraintSet.h

@@ -1,32 +0,0 @@
-// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
-
-#pragma once
-
-#include "Luau/Constraint.h"
-#include "Luau/DenseHash.h"
-#include "Luau/Error.h"
-
-#include <vector>
-
-namespace Luau
-{
-
-struct ConstraintSet
-{
-    NotNull<Scope> rootScope;
-
-    std::vector<ConstraintPtr> constraints;
-
-    // The set of all free types created during constraint generation
-    DenseHashSet<TypeId> freeTypes{nullptr};
-
-    // Map a function's signature scope back to its signature type.   Once we've
-    // dispatched all of the constraints pertaining to a particular free type,
-    // we use this mapping to generalize that free type.
-    DenseHashMap<Scope*, TypeId> scopeToFunction{nullptr};
-
-    // It is pretty uncommon for constraint generation to itself produce errors, but it can happen.
-    std::vector<TypeError> errors;
-};
-
-}

Analysis/include/Luau/ConstraintSolver.h

@@ -3,7 +3,6 @@
 #pragma once
 
 #include "Luau/Constraint.h"
-#include "Luau/ConstraintSet.h"
 #include "Luau/DataFlowGraph.h"
 #include "Luau/DenseHash.h"
 #include "Luau/EqSatSimplification.h"
@@ -88,7 +87,6 @@ struct ConstraintSolver
     NotNull<Simplifier> simplifier;
     NotNull<TypeFunctionRuntime> typeFunctionRuntime;
     // The entire set of constraints that the solver is trying to resolve.
-    ConstraintSet constraintSet;
     std::vector<NotNull<Constraint>> constraints;
     NotNull<DenseHashMap<Scope*, TypeId>> scopeToFunction;
     NotNull<Scope> rootScope;
@@ -142,19 +140,6 @@ struct ConstraintSolver
 
     DenseHashMap<TypeId, const Constraint*> typeFunctionsToFinalize{nullptr};
 
-    explicit ConstraintSolver(
-        NotNull<Normalizer> normalizer,
-        NotNull<Simplifier> simplifier,
-        NotNull<TypeFunctionRuntime> typeFunctionRuntime,
-        ModuleName moduleName,
-        NotNull<ModuleResolver> moduleResolver,
-        std::vector<RequireCycle> requireCycles,
-        DcrLogger* logger,
-        NotNull<const DataFlowGraph> dfg,
-        TypeCheckLimits limits,
-        ConstraintSet constraintSet
-    );
-
     explicit ConstraintSolver(
         NotNull<Normalizer> normalizer,
         NotNull<Simplifier> simplifier,
@@ -189,9 +174,6 @@ struct ConstraintSolver
     bool isDone() const;
 
 private:
-    /// A helper that does most of the setup work that is shared between the two constructors.
-    void initFreeTypeTracking();
-
     void generalizeOneType(TypeId ty);
 
     /**
@@ -383,7 +365,7 @@ public:
      * @returns a non-free type that generalizes the argument, or `std::nullopt` if one
      * does not exist
      */
-    std::optional<TypeId> generalizeFreeType(NotNull<Scope> scope, TypeId type);
+    std::optional<TypeId> generalizeFreeType(NotNull<Scope> scope, TypeId type, bool avoidSealingTables = false);
 
     /**
      * Checks the existing set of constraints to see if there exist any that contain
@@ -450,10 +432,6 @@ public:
     void fillInDiscriminantTypes(NotNull<const Constraint> constraint, const std::vector<std::optional<TypeId>>& discriminantTypes);
 };
 
-/** Borrow a vector of pointers from a vector of owning pointers to constraints.
- */
-std::vector<NotNull<Constraint>> borrowConstraints(const std::vector<ConstraintPtr>& constraints);
-
 void dump(NotNull<Scope> rootScope, struct ToStringOptions& opts);
 
 } // namespace Luau

Analysis/include/Luau/DataFlowGraph.h

@@ -38,6 +38,8 @@ struct DataFlowGraph
     DefId getDef(const AstExpr* expr) const;
     // Look up the definition optionally, knowing it may not be present.
     std::optional<DefId> getDefOptional(const AstExpr* expr) const;
+    // Look up for the rvalue def for a compound assignment.
+    std::optional<DefId> getRValueDefForCompoundAssign(const AstExpr* expr) const;
 
     DefId getDef(const AstLocal* local) const;
 
@@ -64,6 +66,10 @@ private:
     // All keys in this maps are really only statements that ambiently declares a symbol.
     DenseHashMap<const AstStat*, const Def*> declaredDefs{nullptr};
 
+    // Compound assignments are in a weird situation where the local being assigned to is also being used at its
+    // previous type implicitly in an rvalue position. This map provides the previous binding.
+    DenseHashMap<const AstExpr*, const Def*> compoundAssignDefs{nullptr};
+
     DenseHashMap<const AstExpr*, const RefinementKey*> astRefinementKeys{nullptr};
     friend struct DataFlowGraphBuilder;
 };
@@ -129,8 +135,8 @@ private:
 
     /// A stack of scopes used by the visitor to see where we are.
     ScopeStack scopeStack;
-    NotNull<DfgScope> currentScope();
+
-    DfgScope* currentScope_DEPRECATED();
+    DfgScope* currentScope();
 
     struct FunctionCapture
     {
@@ -148,8 +154,8 @@ private:
     void joinBindings(DfgScope* p, const DfgScope& a, const DfgScope& b);
     void joinProps(DfgScope* p, const DfgScope& a, const DfgScope& b);
 
-    DefId lookup(Symbol symbol, Location location);
+    DefId lookup(Symbol symbol);
-    DefId lookup(DefId def, const std::string& key, Location location);
+    DefId lookup(DefId def, const std::string& key);
 
     ControlFlow visit(AstStatBlock* b);
     ControlFlow visitBlockWithoutChildScope(AstStatBlock* b);
@@ -173,7 +179,7 @@ private:
     ControlFlow visit(AstStatTypeFunction* f);
     ControlFlow visit(AstStatDeclareGlobal* d);
     ControlFlow visit(AstStatDeclareFunction* d);
-    ControlFlow visit(AstStatDeclareExternType* d);
+    ControlFlow visit(AstStatDeclareClass* d);
     ControlFlow visit(AstStatError* error);
 
     DataFlowResult visitExpr(AstExpr* e);

Analysis/include/Luau/Def.h

@@ -4,8 +4,7 @@
 #include "Luau/NotNull.h"
 #include "Luau/TypedAllocator.h"
 #include "Luau/Variant.h"
-#include "Luau/Location.h"
+
-#include "Luau/Symbol.h"
 #include <string>
 #include <optional>
 
@@ -14,7 +13,6 @@ namespace Luau
 
 struct Def;
 using DefId = NotNull<const Def>;
-struct AstLocal;
 
 /**
  * A cell is a "single-object" value.
@@ -66,8 +64,6 @@ struct Def
     using V = Variant<struct Cell, struct Phi>;
 
     V v;
-    Symbol name;
-    Location location;
 };
 
 template<typename T>
@@ -83,7 +79,7 @@ struct DefArena
 {
     TypedAllocator<Def> allocator;
 
-    DefId freshCell(Symbol sym, Location location, bool subscripted = false);
+    DefId freshCell(bool subscripted = false);
     DefId phi(DefId a, DefId b);
     DefId phi(const std::vector<DefId>& defs);
 };

Analysis/include/Luau/Error.h

@@ -332,11 +332,11 @@ struct TypePackMismatch
     bool operator==(const TypePackMismatch& rhs) const;
 };
 
-struct DynamicPropertyLookupOnExternTypesUnsafe
+struct DynamicPropertyLookupOnClassesUnsafe
 {
     TypeId ty;
 
-    bool operator==(const DynamicPropertyLookupOnExternTypesUnsafe& rhs) const;
+    bool operator==(const DynamicPropertyLookupOnClassesUnsafe& rhs) const;
 };
 
 struct UninhabitedTypeFunction
@@ -455,13 +455,6 @@ struct UserDefinedTypeFunctionError
     bool operator==(const UserDefinedTypeFunctionError& rhs) const;
 };
 
-struct ReservedIdentifier
-{
-    std::string name;
-
-    bool operator==(const ReservedIdentifier& rhs) const;
-};
-
 using TypeErrorData = Variant<
     TypeMismatch,
     UnknownSymbol,
@@ -499,7 +492,7 @@ using TypeErrorData = Variant<
     TypesAreUnrelated,
     NormalizationTooComplex,
     TypePackMismatch,
-    DynamicPropertyLookupOnExternTypesUnsafe,
+    DynamicPropertyLookupOnClassesUnsafe,
     UninhabitedTypeFunction,
     UninhabitedTypePackFunction,
     WhereClauseNeeded,
@@ -511,8 +504,7 @@ using TypeErrorData = Variant<
     UnexpectedTypeInSubtyping,
     UnexpectedTypePackInSubtyping,
     ExplicitFunctionAnnotationRecommended,
-    UserDefinedTypeFunctionError,
+    UserDefinedTypeFunctionError>;
-    ReservedIdentifier>;
 
 struct TypeErrorSummary
 {

Analysis/include/Luau/FileResolver.h

@@ -20,7 +20,7 @@ struct SourceCode
         None,
         Module,
         Script,
-        Local_DEPRECATED
+        Local
     };
 
     std::string source;
@@ -117,7 +117,8 @@ struct FileResolver
         return std::nullopt;
     }
 
-    std::optional<RequireSuggestions> getRequireSuggestions(const ModuleName& requirer, const std::optional<std::string>& pathString) const;
+    // Make non-virtual when removing FFlagLuauImproveRequireByStringAutocomplete.
+    virtual std::optional<RequireSuggestions> getRequireSuggestions(const ModuleName& requirer, const std::optional<std::string>& pathString) const;
 
     std::shared_ptr<RequireSuggester> requireSuggester;
 };

Analysis/include/Luau/FragmentAutocomplete.h

@@ -49,8 +49,6 @@ struct FragmentAutocompleteAncestryResult
     std::vector<AstLocal*> localStack;
     std::vector<AstNode*> ancestry;
     AstStat* nearestStatement = nullptr;
-    AstStatBlock* parentBlock = nullptr;
-    Location fragmentSelectionRegion;
 };
 
 struct FragmentParseResult
@@ -61,7 +59,6 @@ struct FragmentParseResult
     AstStat* nearestStatement = nullptr;
     std::vector<Comment> commentLocations;
     std::unique_ptr<Allocator> alloc = std::make_unique<Allocator>();
-    Position scopePos{0, 0};
 };
 
 struct FragmentTypeCheckResult
@@ -75,33 +72,14 @@ struct FragmentAutocompleteResult
 {
     ModulePtr incrementalModule;
     Scope* freshScope;
-    TypeArena arenaForAutocomplete_DEPRECATED;
+    TypeArena arenaForAutocomplete;
     AutocompleteResult acResults;
 };
 
-struct FragmentRegion
+FragmentAutocompleteAncestryResult findAncestryForFragmentParse(AstStatBlock* root, const Position& cursorPos);
-{
-    Location fragmentLocation;
-    AstStat* nearestStatement = nullptr; // used for tests
-    AstStatBlock* parentBlock = nullptr; // used for scope detection
-};
-
-std::optional<Position> blockDiffStart(AstStatBlock* blockOld, AstStatBlock* blockNew, AstStat* nearestStatementNewAst);
-FragmentRegion getFragmentRegion(AstStatBlock* root, const Position& cursorPosition);
-FragmentAutocompleteAncestryResult findAncestryForFragmentParse(AstStatBlock* stale, const Position& cursorPos, AstStatBlock* lastGoodParse);
-FragmentAutocompleteAncestryResult findAncestryForFragmentParse_DEPRECATED(AstStatBlock* root, const Position& cursorPos);
-
-std::optional<FragmentParseResult> parseFragment_DEPRECATED(
-    AstStatBlock* root,
-    AstNameTable* names,
-    std::string_view src,
-    const Position& cursorPos,
-    std::optional<Position> fragmentEndPosition
-);
 
 std::optional<FragmentParseResult> parseFragment(
-    AstStatBlock* stale,
+    AstStatBlock* root,
-    AstStatBlock* mostRecentParse,
     AstNameTable* names,
     std::string_view src,
     const Position& cursorPos,
@@ -115,7 +93,6 @@ std::pair<FragmentTypeCheckStatus, FragmentTypeCheckResult> typecheckFragment(
     std::optional<FrontendOptions> opts,
     std::string_view src,
     std::optional<Position> fragmentEndPosition,
-    AstStatBlock* recentParse = nullptr,
     IFragmentAutocompleteReporter* reporter = nullptr
 );
 
@@ -127,7 +104,6 @@ FragmentAutocompleteResult fragmentAutocomplete(
     std::optional<FrontendOptions> opts,
     StringCompletionCallback callback,
     std::optional<Position> fragmentEndPosition = std::nullopt,
-    AstStatBlock* recentParse = nullptr,
     IFragmentAutocompleteReporter* reporter = nullptr
 );
 

Analysis/include/Luau/Frontend.h

@@ -10,6 +10,7 @@
 #include "Luau/Set.h"
 #include "Luau/TypeCheckLimits.h"
 #include "Luau/Variant.h"
+#include "Luau/AnyTypeSummary.h"
 
 #include <mutex>
 #include <string>
@@ -33,6 +34,7 @@ struct HotComment;
 struct BuildQueueItem;
 struct BuildQueueWorkState;
 struct FrontendCancellationToken;
+struct AnyTypeSummary;
 
 struct LoadDefinitionFileResult
 {
@@ -215,6 +217,11 @@ struct Frontend
         std::function<void(std::function<void()> task)> executeTask = {},
         std::function<bool(size_t done, size_t total)> progress = {}
     );
+    std::vector<ModuleName> checkQueuedModules_DEPRECATED(
+        std::optional<FrontendOptions> optionOverride = {},
+        std::function<void(std::function<void()> task)> executeTask = {},
+        std::function<bool(size_t done, size_t total)> progress = {}
+    );
 
     std::optional<CheckResult> getCheckResult(const ModuleName& name, bool accumulateNested, bool forAutocomplete = false);
     std::vector<ModuleName> getRequiredScripts(const ModuleName& name);

Analysis/include/Luau/Generalization.h

@@ -8,75 +8,13 @@
 namespace Luau
 {
 
-template<typename TID>
-struct GeneralizationParams
-{
-    bool foundOutsideFunctions = false;
-    size_t useCount = 0;
-    Polarity polarity = Polarity::None;
-};
-
-template<typename TID>
-struct GeneralizationResult
-{
-    std::optional<TID> result;
-
-    // True if the provided type was replaced with a generic.
-    bool wasReplacedByGeneric = false;
-
-    bool resourceLimitsExceeded = false;
-
-    explicit operator bool() const
-    {
-        return bool(result);
-    }
-};
-
-// Replace a single free type by its bounds according to the polarity provided.
-GeneralizationResult<TypeId> generalizeType(
-    NotNull<TypeArena> arena,
-    NotNull<BuiltinTypes> builtinTypes,
-    NotNull<Scope> scope,
-    TypeId freeTy,
-    const GeneralizationParams<TypeId>& params
-);
-
-// Generalize one type pack
-GeneralizationResult<TypePackId> generalizeTypePack(
-    NotNull<TypeArena> arena,
-    NotNull<BuiltinTypes> builtinTypes,
-    NotNull<Scope> scope,
-    TypePackId tp,
-    const GeneralizationParams<TypePackId>& params
-);
-
-void sealTable(NotNull<Scope> scope, TypeId ty);
-
-/** Attempt to generalize a type.
- *
- * If generalizationTarget is set, then only that type will be replaced by its
- * bounds.  The way this is intended to be used is that ty is some function that
- * is not fully generalized, and generalizationTarget is a type within its
- * signature.  There should be no further constraints that could affect the
- * bounds of generalizationTarget.
- *
- * Returns nullopt if generalization failed due to resources limits.
- */
 std::optional<TypeId> generalize(
     NotNull<TypeArena> arena,
     NotNull<BuiltinTypes> builtinTypes,
     NotNull<Scope> scope,
     NotNull<DenseHashSet<TypeId>> cachedTypes,
     TypeId ty,
-    std::optional<TypeId> generalizationTarget = {}
+    /* avoid sealing tables*/ bool avoidSealingTables = false
 );
 
-void pruneUnnecessaryGenerics(
+}
-    NotNull<TypeArena> arena,
-    NotNull<BuiltinTypes> builtinTypes,
-    NotNull<Scope> scope,
-    NotNull<DenseHashSet<TypeId>> cachedTypes,
-    TypeId ty
-);
-
-} // namespace Luau

Analysis/include/Luau/InferPolarity.h

@@ -1,16 +0,0 @@
-// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
-#pragma once
-
-#include "Luau/NotNull.h"
-#include "Luau/TypeFwd.h"
-
-namespace Luau
-{
-
-struct Scope;
-struct TypeArena;
-
-void inferGenericPolarities(NotNull<TypeArena> arena, NotNull<Scope> scope, TypeId ty);
-void inferGenericPolarities(NotNull<TypeArena> arena, NotNull<Scope> scope, TypePackId tp);
-
-} // namespace Luau

Analysis/include/Luau/InsertionOrderedMap.h

@@ -67,19 +67,6 @@ public:
             return &pairs.at(it->second).second;
     }
 
-    V& operator[](const K& k)
-    {
-        auto it = indices.find(k);
-        if (it == indices.end())
-        {
-            pairs.push_back(std::make_pair(k, V()));
-            indices[k] = pairs.size() - 1;
-            return pairs.back().second;
-        }
-        else
-            return pairs.at(it->second).second;
-    }
-
     const_iterator begin() const
     {
         return pairs.begin();

Analysis/include/Luau/Instantiation.h

@@ -133,9 +133,9 @@ struct GenericTypeFinder : TypeOnceVisitor
         return false;
     }
 
-    bool visit(TypeId ty, const Luau::ExternType&) override
+    bool visit(TypeId ty, const Luau::ClassType&) override
     {
-        // During function instantiation, extern types are not traversed even if they have generics
+        // During function instantiation, classes are not traversed even if they have generics
         return false;
     }
 };

Analysis/include/Luau/Module.h

@@ -8,6 +8,7 @@
 #include "Luau/ParseResult.h"
 #include "Luau/Scope.h"
 #include "Luau/TypeArena.h"
+#include "Luau/AnyTypeSummary.h"
 #include "Luau/DataFlowGraph.h"
 
 #include <memory>
@@ -15,16 +16,19 @@
 #include <unordered_map>
 #include <optional>
 
+LUAU_FASTFLAG(LuauIncrementalAutocompleteCommentDetection)
+
 namespace Luau
 {
 
-using LogLuauProc = void (*)(std::string_view, std::string_view);
+using LogLuauProc = void (*)(std::string_view);
 extern LogLuauProc logLuau;
 
 void setLogLuau(LogLuauProc ll);
 void resetLogLuauProc();
 
 struct Module;
+struct AnyTypeSummary;
 
 using ScopePtr = std::shared_ptr<struct Scope>;
 using ModulePtr = std::shared_ptr<Module>;
@@ -82,6 +86,10 @@ struct Module
     TypeArena interfaceTypes;
     TypeArena internalTypes;
 
+    // Summary of Ast Nodes that either contain
+    // user annotated anys or typechecker inferred anys
+    AnyTypeSummary ats{};
+
     // Scopes and AST types refer to parse data, so we need to keep that alive
     std::shared_ptr<Allocator> allocator;
     std::shared_ptr<AstNameTable> names;

Analysis/include/Luau/NonStrictTypeChecker.h

@@ -1,10 +1,9 @@
 // This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
 #pragma once
 
-#include "Luau/DataFlowGraph.h"
-#include "Luau/EqSatSimplification.h"
 #include "Luau/Module.h"
 #include "Luau/NotNull.h"
+#include "Luau/DataFlowGraph.h"
 
 namespace Luau
 {

Analysis/include/Luau/Normalize.h

@@ -181,7 +181,7 @@ struct NormalizedStringType
 
 bool isSubtype(const NormalizedStringType& subStr, const NormalizedStringType& superStr);
 
-struct NormalizedExternType
+struct NormalizedClassType
 {
     /** Has the following structure:
      *
@@ -192,7 +192,7 @@ struct NormalizedExternType
      *
      * Each TypeId is a class type.
      */
-    std::unordered_map<TypeId, TypeIds> externTypes;
+    std::unordered_map<TypeId, TypeIds> classes;
 
     /**
      * In order to maintain a consistent insertion order, we use this vector to
@@ -245,7 +245,7 @@ enum class NormalizationResult
 };
 
 // A normalized type is either any, unknown, or one of the form P | T | F | G where
-// * P is a union of primitive types (including singletons, extern types and the error type)
+// * P is a union of primitive types (including singletons, classes and the error type)
 // * T is a union of table types
 // * F is a union of an intersection of function types
 // * G is a union of generic/free/blocked types, intersected with a normalized type
@@ -260,7 +260,7 @@ struct NormalizedType
     // This type is either never, boolean type, or a boolean singleton.
     TypeId booleans;
 
-    NormalizedExternType externTypes;
+    NormalizedClassType classes;
 
     // The error part of the type.
     // This type is either never or the error type.
@@ -333,7 +333,7 @@ struct NormalizedType
     // Helpers that improve readability of the above (they just say if the component is present)
     bool hasTops() const;
     bool hasBooleans() const;
-    bool hasExternTypes() const;
+    bool hasClasses() const;
     bool hasErrors() const;
     bool hasNils() const;
     bool hasNumbers() const;
@@ -391,10 +391,10 @@ public:
     void unionTysWithTy(TypeIds& here, TypeId there);
     TypeId unionOfTops(TypeId here, TypeId there);
     TypeId unionOfBools(TypeId here, TypeId there);
-    void unionExternTypesWithExternType(TypeIds& heres, TypeId there);
+    void unionClassesWithClass(TypeIds& heres, TypeId there);
-    void unionExternTypes(TypeIds& heres, const TypeIds& theres);
+    void unionClasses(TypeIds& heres, const TypeIds& theres);
-    void unionExternTypesWithExternType(NormalizedExternType& heres, TypeId there);
+    void unionClassesWithClass(NormalizedClassType& heres, TypeId there);
-    void unionExternTypes(NormalizedExternType& heres, const NormalizedExternType& theres);
+    void unionClasses(NormalizedClassType& heres, const NormalizedClassType& theres);
     void unionStrings(NormalizedStringType& here, const NormalizedStringType& there);
     std::optional<TypePackId> unionOfTypePacks(TypePackId here, TypePackId there);
     std::optional<TypeId> unionOfFunctions(TypeId here, TypeId there);
@@ -423,8 +423,8 @@ public:
     // ------- Normalizing intersections
     TypeId intersectionOfTops(TypeId here, TypeId there);
     TypeId intersectionOfBools(TypeId here, TypeId there);
-    void intersectExternTypes(NormalizedExternType& heres, const NormalizedExternType& theres);
+    void intersectClasses(NormalizedClassType& heres, const NormalizedClassType& theres);
-    void intersectExternTypesWithExternType(NormalizedExternType& heres, TypeId there);
+    void intersectClassesWithClass(NormalizedClassType& heres, TypeId there);
     void intersectStrings(NormalizedStringType& here, const NormalizedStringType& there);
     std::optional<TypePackId> intersectionOfTypePacks(TypePackId here, TypePackId there);
     std::optional<TypeId> intersectionOfTables(TypeId here, TypeId there, SeenTablePropPairs& seenTablePropPairs, Set<TypeId>& seenSet);

Analysis/include/Luau/Polarity.h

@@ -1,68 +0,0 @@
-// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
-#pragma once
-
-#include <cstdint>
-
-namespace Luau
-{
-
-enum struct Polarity : uint8_t
-{
-    None = 0b000,
-    Positive = 0b001,
-    Negative = 0b010,
-    Mixed = 0b011,
-    Unknown = 0b100,
-};
-
-inline Polarity operator|(Polarity lhs, Polarity rhs)
-{
-    return Polarity(uint8_t(lhs) | uint8_t(rhs));
-}
-
-inline Polarity& operator|=(Polarity& lhs, Polarity rhs)
-{
-    lhs = lhs | rhs;
-    return lhs;
-}
-
-inline Polarity operator&(Polarity lhs, Polarity rhs)
-{
-    return Polarity(uint8_t(lhs) & uint8_t(rhs));
-}
-
-inline Polarity& operator&=(Polarity& lhs, Polarity rhs)
-{
-    lhs = lhs & rhs;
-    return lhs;
-}
-
-inline bool isPositive(Polarity p)
-{
-    return bool(p & Polarity::Positive);
-}
-
-inline bool isNegative(Polarity p)
-{
-    return bool(p & Polarity::Negative);
-}
-
-inline bool isKnown(Polarity p)
-{
-    return p != Polarity::Unknown;
-}
-
-inline Polarity invert(Polarity p)
-{
-    switch (p)
-    {
-    case Polarity::Positive:
-        return Polarity::Negative;
-    case Polarity::Negative:
-        return Polarity::Positive;
-    default:
-        return p;
-    }
-}
-
-} // namespace Luau

Analysis/include/Luau/Quantify.h

@@ -16,7 +16,7 @@ struct Scope;
 
 void quantify(TypeId ty, TypeLevel level);
 
-// TODO: This is eerily similar to the pattern that NormalizedExternType
+// TODO: This is eerily similar to the pattern that NormalizedClassType
 // implements. We could, and perhaps should, merge them together.
 template<typename K, typename V>
 struct OrderedMap

Analysis/include/Luau/Scope.h

@@ -40,7 +40,7 @@ struct Scope
     // All the children of this scope.
     std::vector<NotNull<Scope>> children;
     std::unordered_map<Symbol, Binding> bindings;
-    TypePackId returnType = nullptr;
+    TypePackId returnType;
     std::optional<TypePackId> varargPack;
 
     TypeLevel level;
@@ -100,7 +100,6 @@ struct Scope
     std::unordered_map<Name, TypePackId> typeAliasTypePackParameters;
 
     std::optional<std::vector<TypeId>> interiorFreeTypes;
-    std::optional<std::vector<TypePackId>> interiorFreeTypePacks;
 };
 
 // Returns true iff the left scope encloses the right scope.  A Scope* equal to

Analysis/include/Luau/Simplify.h

@@ -24,9 +24,6 @@ SimplifyResult simplifyIntersection(NotNull<BuiltinTypes> builtinTypes, NotNull<
 
 SimplifyResult simplifyUnion(NotNull<BuiltinTypes> builtinTypes, NotNull<TypeArena> arena, TypeId left, TypeId right);
 
-SimplifyResult simplifyIntersectWithTruthy(NotNull<BuiltinTypes> builtinTypes, NotNull<TypeArena> arena, TypeId target);
-SimplifyResult simplifyIntersectWithFalsy(NotNull<BuiltinTypes> builtinTypes, NotNull<TypeArena> arena, TypeId target);
-
 enum class Relation
 {
     Disjoint,   // No A is a B or vice versa

Analysis/include/Luau/Substitution.h

@@ -86,7 +86,6 @@ struct TarjanNode
 struct Tarjan
 {
     Tarjan();
-    virtual ~Tarjan() = default;
 
     // Vertices (types and type packs) are indexed, using pre-order traversal.
     DenseHashMap<TypeId, int> typeToIndex{nullptr};
@@ -122,7 +121,7 @@ struct Tarjan
     void visitChildren(TypePackId tp, int index);
 
     void visitChild(TypeId ty);
-    void visitChild(TypePackId tp);
+    void visitChild(TypePackId ty);
 
     template<typename Ty>
     void visitChild(std::optional<Ty> ty)
@@ -133,7 +132,7 @@ struct Tarjan
 
     // Visit the root vertex.
     TarjanResult visitRoot(TypeId ty);
-    TarjanResult visitRoot(TypePackId tp);
+    TarjanResult visitRoot(TypePackId ty);
 
     // Used to reuse the object for a new operation
     void clearTarjan(const TxnLog* log);
@@ -151,12 +150,26 @@ struct Tarjan
     void visitSCC(int index);
 
     // Each subclass can decide to ignore some nodes.
-    virtual bool ignoreChildren(TypeId ty);
+    virtual bool ignoreChildren(TypeId ty)
-    virtual bool ignoreChildren(TypePackId ty);
+    {
+        return false;
+    }
+
+    virtual bool ignoreChildren(TypePackId ty)
+    {
+        return false;
+    }
 
     // Some subclasses might ignore children visit, but not other actions like replacing the children
-    virtual bool ignoreChildrenVisit(TypeId ty);
+    virtual bool ignoreChildrenVisit(TypeId ty)
-    virtual bool ignoreChildrenVisit(TypePackId ty);
+    {
+        return ignoreChildren(ty);
+    }
+
+    virtual bool ignoreChildrenVisit(TypePackId ty)
+    {
+        return ignoreChildren(ty);
+    }
 
     // Subclasses should say which vertices are dirty,
     // and what to do with dirty vertices.
@@ -171,7 +184,6 @@ struct Tarjan
 struct Substitution : Tarjan
 {
 protected:
-    explicit Substitution(TypeArena* arena);
     Substitution(const TxnLog* log_, TypeArena* arena);
 
     /*
@@ -220,23 +232,28 @@ public:
     virtual TypeId clean(TypeId ty) = 0;
     virtual TypePackId clean(TypePackId tp) = 0;
 
-protected:
     // Helper functions to create new types (used by subclasses)
     template<typename T>
-    TypeId addType(T tv)
+    TypeId addType(const T& tv)
     {
-        return arena->addType(std::move(tv));
+        return arena->addType(tv);
     }
 
     template<typename T>
-    TypePackId addTypePack(T tp)
+    TypePackId addTypePack(const T& tp)
     {
-        return arena->addTypePack(TypePackVar{std::move(tp)});
+        return arena->addTypePack(TypePackVar{tp});
     }
 
 private:
     template<typename Ty>
-    std::optional<Ty> replace(std::optional<Ty> ty);
+    std::optional<Ty> replace(std::optional<Ty> ty)
+    {
+        if (ty)
+            return replace(*ty);
+        else
+            return std::nullopt;
+    }
 };
 
 } // namespace Luau

Analysis/include/Luau/Subtyping.h

@@ -22,7 +22,7 @@ struct InternalErrorReporter;
 
 class TypeIds;
 class Normalizer;
-struct NormalizedExternType;
+struct NormalizedClassType;
 struct NormalizedFunctionType;
 struct NormalizedStringType;
 struct NormalizedType;
@@ -121,7 +121,7 @@ struct SubtypingEnvironment
     DenseHashMap<TypePackId, TypePackId> mappedGenericPacks{nullptr};
 
     /*
-     * See the test cyclic_tables_are_assumed_to_be_compatible_with_extern_types for
+     * See the test cyclic_tables_are_assumed_to_be_compatible_with_classes for
      * details.
      *
      * An empty value is equivalent to a nonexistent key.
@@ -229,8 +229,9 @@ private:
     SubtypingResult isCovariantWith(SubtypingEnvironment& env, const TableType* subTable, const TableType* superTable, NotNull<Scope> scope);
     SubtypingResult isCovariantWith(SubtypingEnvironment& env, const MetatableType* subMt, const MetatableType* superMt, NotNull<Scope> scope);
     SubtypingResult isCovariantWith(SubtypingEnvironment& env, const MetatableType* subMt, const TableType* superTable, NotNull<Scope> scope);
-    SubtypingResult isCovariantWith(SubtypingEnvironment& env, const ExternType* subExternType, const ExternType* superExternType, NotNull<Scope> scope);
+    SubtypingResult isCovariantWith(SubtypingEnvironment& env, const ClassType* subClass, const ClassType* superClass, NotNull<Scope> scope);
-    SubtypingResult isCovariantWith(SubtypingEnvironment& env, TypeId subTy, const ExternType* subExternType, TypeId superTy, const TableType* superTable, NotNull<Scope>);
+    SubtypingResult
+    isCovariantWith(SubtypingEnvironment& env, TypeId subTy, const ClassType* subClass, TypeId superTy, const TableType* superTable, NotNull<Scope>);
     SubtypingResult isCovariantWith(
         SubtypingEnvironment& env,
         const FunctionType* subFunction,
@@ -258,11 +259,11 @@ private:
     );
     SubtypingResult isCovariantWith(
         SubtypingEnvironment& env,
-        const NormalizedExternType& subExternType,
+        const NormalizedClassType& subClass,
-        const NormalizedExternType& superExternType,
+        const NormalizedClassType& superClass,
         NotNull<Scope> scope
     );
-    SubtypingResult isCovariantWith(SubtypingEnvironment& env, const NormalizedExternType& subExternType, const TypeIds& superTables, NotNull<Scope> scope);
+    SubtypingResult isCovariantWith(SubtypingEnvironment& env, const NormalizedClassType& subClass, const TypeIds& superTables, NotNull<Scope> scope);
     SubtypingResult isCovariantWith(
         SubtypingEnvironment& env,
         const NormalizedStringType& subString,

Analysis/include/Luau/ToString.h

@@ -44,7 +44,6 @@ struct ToStringOptions
     bool hideTableKind = false;                   // If true, all tables will be surrounded with plain '{}'
     bool hideNamedFunctionTypeParameters = false; // If true, type parameters of functions will be hidden at top-level.
     bool hideFunctionSelfArgument = false;        // If true, `self: X` will be omitted from the function signature if the function has self
-    bool hideTableAliasExpansions = false;        // If true, all table aliases will not be expanded
     bool useQuestionMarks = true;                 // If true, use a postfix ? for options, else write them out as unions that include nil.
     size_t maxTableLength = size_t(FInt::LuauTableTypeMaximumStringifierLength); // Only applied to TableTypes
     size_t maxTypeLength = size_t(FInt::LuauTypeMaximumStringifierLength);

Analysis/include/Luau/TxnLog.h

@@ -192,6 +192,16 @@ struct TxnLog
     // The pointer returned lives until `commit` or `clear` is called.
     PendingTypePack* changeLevel(TypePackId tp, TypeLevel newLevel);
 
+    // Queues the replacement of a type's scope with the provided scope.
+    //
+    // The pointer returned lives until `commit` or `clear` is called.
+    PendingType* changeScope(TypeId ty, NotNull<Scope> scope);
+
+    // Queues the replacement of a type pack's scope with the provided scope.
+    //
+    // The pointer returned lives until `commit` or `clear` is called.
+    PendingTypePack* changeScope(TypePackId tp, NotNull<Scope> scope);
+
     // Queues a replacement of a table type with another table type with a new
     // indexer.
     //

Analysis/include/Luau/Type.h

@@ -5,11 +5,10 @@
 
 #include "Luau/Ast.h"
 #include "Luau/Common.h"
+#include "Luau/Refinement.h"
 #include "Luau/DenseHash.h"
 #include "Luau/NotNull.h"
-#include "Luau/Polarity.h"
 #include "Luau/Predicate.h"
-#include "Luau/Refinement.h"
 #include "Luau/Unifiable.h"
 #include "Luau/Variant.h"
 #include "Luau/VecDeque.h"
@@ -20,6 +19,7 @@
 #include <optional>
 #include <set>
 #include <string>
+#include <unordered_map>
 #include <vector>
 
 LUAU_FASTINT(LuauTableTypeMaximumStringifierLength)
@@ -72,8 +72,12 @@ struct FreeType
     // New constructors
     explicit FreeType(TypeLevel level, TypeId lowerBound, TypeId upperBound);
     // This one got promoted to explicit
-    explicit FreeType(Scope* scope, TypeId lowerBound, TypeId upperBound, Polarity polarity = Polarity::Unknown);
+    explicit FreeType(Scope* scope, TypeId lowerBound, TypeId upperBound);
     explicit FreeType(Scope* scope, TypeLevel level, TypeId lowerBound, TypeId upperBound);
+    // Old constructors
+    explicit FreeType(TypeLevel level);
+    explicit FreeType(Scope* scope);
+    FreeType(Scope* scope, TypeLevel level);
 
     int index;
     TypeLevel level;
@@ -87,8 +91,6 @@ struct FreeType
     // Only used under local type inference
     TypeId lowerBound = nullptr;
     TypeId upperBound = nullptr;
-
-    Polarity polarity = Polarity::Unknown;
 };
 
 struct GenericType
@@ -97,8 +99,8 @@ struct GenericType
     GenericType();
 
     explicit GenericType(TypeLevel level);
-    explicit GenericType(const Name& name, Polarity polarity = Polarity::Unknown);
+    explicit GenericType(const Name& name);
-    explicit GenericType(Scope* scope, Polarity polarity = Polarity::Unknown);
+    explicit GenericType(Scope* scope);
 
     GenericType(TypeLevel level, const Name& name);
     GenericType(Scope* scope, const Name& name);
@@ -108,8 +110,6 @@ struct GenericType
     Scope* scope = nullptr;
     Name name;
     bool explicitName = false;
-
-    Polarity polarity = Polarity::Unknown;
 };
 
 // When an equality constraint is found, it is then "bound" to that type,
@@ -287,7 +287,7 @@ struct MagicFunctionCallContext
 {
     NotNull<struct ConstraintSolver> solver;
     NotNull<const Constraint> constraint;
-    NotNull<const AstExprCall> callSite;
+    const class AstExprCall* callSite;
     TypePackId arguments;
     TypePackId result;
 };
@@ -348,8 +348,10 @@ struct FunctionType
     );
 
     // Local monomorphic function
+    FunctionType(TypeLevel level, TypePackId argTypes, TypePackId retTypes, std::optional<FunctionDefinition> defn = {}, bool hasSelf = false);
     FunctionType(
         TypeLevel level,
+        Scope* scope,
         TypePackId argTypes,
         TypePackId retTypes,
         std::optional<FunctionDefinition> defn = {},
@@ -366,6 +368,16 @@ struct FunctionType
         std::optional<FunctionDefinition> defn = {},
         bool hasSelf = false
     );
+    FunctionType(
+        TypeLevel level,
+        Scope* scope,
+        std::vector<TypeId> generics,
+        std::vector<TypePackId> genericPacks,
+        TypePackId argTypes,
+        TypePackId retTypes,
+        std::optional<FunctionDefinition> defn = {},
+        bool hasSelf = false
+    );
 
     std::optional<FunctionDefinition> definition;
     /// These should all be generic
@@ -374,6 +386,7 @@ struct FunctionType
     std::vector<std::optional<FunctionArgument>> argNames;
     Tags tags;
     TypeLevel level;
+    Scope* scope = nullptr;
     TypePackId argTypes;
     TypePackId retTypes;
     std::shared_ptr<MagicFunction> magic = nullptr;
@@ -383,7 +396,6 @@ struct FunctionType
     // this flag is used as an optimization to exit early from procedures that manipulate free or generic types.
     bool hasNoFreeOrGenericTypes = false;
     bool isCheckedFunction = false;
-    bool isDeprecatedFunction = false;
 };
 
 enum class TableState
@@ -460,9 +472,7 @@ struct Property
     TypeId type() const;
     void setType(TypeId ty);
 
-    // If this property has a present `writeTy`, set it equal to the `readTy`.
+    // Sets the write type of this property to the read type.
-    // This is to ensure that if we normalize a property that has divergent
-    // read and write types, we make them converge (for now).
     void makeShared();
 
     bool isShared() const;
@@ -507,6 +517,9 @@ struct TableType
     std::optional<TypeId> boundTo;
     Tags tags;
 
+    // Methods of this table that have an untyped self will use the same shared self type.
+    std::optional<TypeId> selfTy;
+
     // We track the number of as-yet-unadded properties to unsealed tables.
     // Some constraints will use this information to decide whether or not they
     // are able to dispatch.
@@ -532,15 +545,15 @@ struct ClassUserData
     virtual ~ClassUserData() {}
 };
 
-/** The type of an external userdata exposed to Luau.
+/** The type of a class.
  *
- * Extern types behave like tables in many ways, but there are some important differences:
+ * Classes behave like tables in many ways, but there are some important differences:
  *
  * The properties of a class are always exactly known.
- * Extern types optionally have a parent type.
+ * Classes optionally have a parent class.
- * Two different extern types that share the same properties are nevertheless distinct and mutually incompatible.
+ * Two different classes that share the same properties are nevertheless distinct and mutually incompatible.
  */
-struct ExternType
+struct ClassType
 {
     using Props = TableType::Props;
 
@@ -554,7 +567,7 @@ struct ExternType
     std::optional<Location> definitionLocation;
     std::optional<TableIndexer> indexer;
 
-    ExternType(
+    ClassType(
         Name name,
         Props props,
         std::optional<TypeId> parent,
@@ -575,7 +588,7 @@ struct ExternType
     {
     }
 
-    ExternType(
+    ClassType(
         Name name,
         Props props,
         std::optional<TypeId> parent,
@@ -775,7 +788,7 @@ using TypeVariant = Unifiable::Variant<
     FunctionType,
     TableType,
     MetatableType,
-    ExternType,
+    ClassType,
     AnyType,
     UnionType,
     IntersectionType,
@@ -868,9 +881,6 @@ struct TypeFun
      */
     TypeId type;
 
-    // The location of where this TypeFun was defined, if available
-    std::optional<Location> definitionLocation;
-
     TypeFun() = default;
 
     explicit TypeFun(TypeId ty)
@@ -878,23 +888,16 @@ struct TypeFun
     {
     }
 
-    TypeFun(std::vector<GenericTypeDefinition> typeParams, TypeId type, std::optional<Location> definitionLocation = std::nullopt)
+    TypeFun(std::vector<GenericTypeDefinition> typeParams, TypeId type)
         : typeParams(std::move(typeParams))
         , type(type)
-        , definitionLocation(definitionLocation)
     {
     }
 
-    TypeFun(
+    TypeFun(std::vector<GenericTypeDefinition> typeParams, std::vector<GenericTypePackDefinition> typePackParams, TypeId type)
-        std::vector<GenericTypeDefinition> typeParams,
-        std::vector<GenericTypePackDefinition> typePackParams,
-        TypeId type,
-        std::optional<Location> definitionLocation = std::nullopt
-    )
         : typeParams(std::move(typeParams))
         , typePackParams(std::move(typePackParams))
         , type(type)
-        , definitionLocation(definitionLocation)
     {
     }
 
@@ -986,7 +989,7 @@ public:
     const TypeId threadType;
     const TypeId bufferType;
     const TypeId functionType;
-    const TypeId externType;
+    const TypeId classType;
     const TypeId tableType;
     const TypeId emptyTableType;
     const TypeId trueType;
@@ -998,7 +1001,6 @@ public:
     const TypeId noRefineType;
     const TypeId falsyType;
     const TypeId truthyType;
-    const TypeId notNilType;
 
     const TypeId optionalNumberType;
     const TypeId optionalStringType;
@@ -1019,10 +1021,10 @@ TypeLevel* getMutableLevel(TypeId ty);
 
 std::optional<TypeLevel> getLevel(TypePackId tp);
 
-const Property* lookupExternTypeProp(const ExternType* cls, const Name& name);
+const Property* lookupClassProp(const ClassType* cls, const Name& name);
 
 // Whether `cls` is a subclass of `parent`
-bool isSubclass(const ExternType* cls, const ExternType* parent);
+bool isSubclass(const ClassType* cls, const ClassType* parent);
 
 Type* asMutable(TypeId ty);
 
@@ -1199,7 +1201,7 @@ private:
     }
 };
 
-TypeId freshType(NotNull<TypeArena> arena, NotNull<BuiltinTypes> builtinTypes, Scope* scope, Polarity polarity = Polarity::Unknown);
+TypeId freshType(NotNull<TypeArena> arena, NotNull<BuiltinTypes> builtinTypes, Scope* scope);
 
 using TypeIdPredicate = std::function<std::optional<TypeId>(TypeId)>;
 std::vector<TypeId> filterMap(TypeId type, TypeIdPredicate predicate);

Analysis/include/Luau/TypeArena.h

@@ -1,7 +1,6 @@
 // This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
 #pragma once
 
-#include "Luau/Polarity.h"
 #include "Luau/TypedAllocator.h"
 #include "Luau/Type.h"
 #include "Luau/TypePack.h"
@@ -37,7 +36,11 @@ struct TypeArena
     TypeId freshType(NotNull<BuiltinTypes> builtins, Scope* scope);
     TypeId freshType(NotNull<BuiltinTypes> builtins, Scope* scope, TypeLevel level);
 
-    TypePackId freshTypePack(Scope* scope, Polarity polarity = Polarity::Unknown);
+    TypeId freshType_DEPRECATED(TypeLevel level);
+    TypeId freshType_DEPRECATED(Scope* scope);
+    TypeId freshType_DEPRECATED(Scope* scope, TypeLevel level);
+
+    TypePackId freshTypePack(Scope* scope);
 
     TypePackId addTypePack(std::initializer_list<TypeId> types);
     TypePackId addTypePack(std::vector<TypeId> types, std::optional<TypePackId> tail = {});

Analysis/include/Luau/TypeAttach.h

@@ -11,7 +11,7 @@ namespace Luau
 struct TypeRehydrationOptions
 {
     std::unordered_set<std::string> bannedNames;
-    bool expandExternTypeProps = false;
+    bool expandClassProps = false;
 };
 
 void attachTypeData(SourceModule& source, Module& result);

Analysis/include/Luau/TypeChecker2.h

@@ -160,7 +160,7 @@ private:
     void visit(AstTypeList types);
     void visit(AstStatDeclareFunction* stat);
     void visit(AstStatDeclareGlobal* stat);
-    void visit(AstStatDeclareExternType* stat);
+    void visit(AstStatDeclareClass* stat);
     void visit(AstStatError* stat);
     void visit(AstExpr* expr, ValueContext context);
     void visit(AstExprGroup* expr, ValueContext context);

Analysis/include/Luau/TypeFunction.h

@@ -155,9 +155,6 @@ struct TypeFunction
 
     /// The reducer function for the type function.
     ReducerFunction<TypeId> reducer;
-
-    /// If true, this type function can reduce even if it is parameterized on a generic.
-    bool canReduceGenerics = false;
 };
 
 /// Represents a type function that may be applied to map a series of types and
@@ -170,9 +167,6 @@ struct TypePackFunction
 
     /// The reducer function for the type pack function.
     ReducerFunction<TypePackId> reducer;
-
-    /// If true, this type function can reduce even if it is parameterized on a generic.
-    bool canReduceGenerics = false;
 };
 
 struct FunctionGraphReductionResult
@@ -183,7 +177,6 @@ struct FunctionGraphReductionResult
     DenseHashSet<TypePackId> blockedPacks{nullptr};
     DenseHashSet<TypeId> reducedTypes{nullptr};
     DenseHashSet<TypePackId> reducedPacks{nullptr};
-    DenseHashSet<TypeId> irreducibleTypes{nullptr};
 };
 
 /**
@@ -254,8 +247,6 @@ struct BuiltinTypeFunctions
     TypeFunction setmetatableFunc;
     TypeFunction getmetatableFunc;
 
-    TypeFunction weakoptionalFunc;
-
     void addToScope(NotNull<TypeArena> arena, NotNull<Scope> scope) const;
 };
 

Analysis/include/Luau/TypeFunctionRuntime.h

@@ -205,7 +205,7 @@ struct TypeFunctionTableType
     std::optional<TypeFunctionTypeId> metatable;
 };
 
-struct TypeFunctionExternType
+struct TypeFunctionClassType
 {
     using Name = std::string;
     using Props = std::map<Name, TypeFunctionProperty>;
@@ -222,7 +222,7 @@ struct TypeFunctionExternType
     std::optional<TypeFunctionTypeId> readParent;
     std::optional<TypeFunctionTypeId> writeParent;
 
-    TypeId externTy;
+    TypeId classTy;
 };
 
 struct TypeFunctionGenericType
@@ -244,7 +244,7 @@ using TypeFunctionTypeVariant = Luau::Variant<
     TypeFunctionNegationType,
     TypeFunctionFunctionType,
     TypeFunctionTableType,
-    TypeFunctionExternType,
+    TypeFunctionClassType,
     TypeFunctionGenericType>;
 
 struct TypeFunctionType

Analysis/include/Luau/TypeFwd.h

@@ -29,7 +29,7 @@ struct SingletonType;
 struct FunctionType;
 struct TableType;
 struct MetatableType;
-struct ExternType;
+struct ClassType;
 struct AnyType;
 struct UnionType;
 struct IntersectionType;

Analysis/include/Luau/TypeInfer.h

@@ -90,11 +90,11 @@ struct TypeChecker
     ControlFlow check(const ScopePtr& scope, TypeId ty, const ScopePtr& funScope, const AstStatLocalFunction& function);
     ControlFlow check(const ScopePtr& scope, const AstStatTypeAlias& typealias);
     ControlFlow check(const ScopePtr& scope, const AstStatTypeFunction& typefunction);
-    ControlFlow check(const ScopePtr& scope, const AstStatDeclareExternType& declaredExternType);
+    ControlFlow check(const ScopePtr& scope, const AstStatDeclareClass& declaredClass);
     ControlFlow check(const ScopePtr& scope, const AstStatDeclareFunction& declaredFunction);
 
     void prototype(const ScopePtr& scope, const AstStatTypeAlias& typealias, int subLevel = 0);
-    void prototype(const ScopePtr& scope, const AstStatDeclareExternType& declaredExternType);
+    void prototype(const ScopePtr& scope, const AstStatDeclareClass& declaredClass);
 
     ControlFlow checkBlock(const ScopePtr& scope, const AstStatBlock& statement);
     ControlFlow checkBlockWithoutRecursionCheck(const ScopePtr& scope, const AstStatBlock& statement);
@@ -130,7 +130,6 @@ struct TypeChecker
         const PredicateVec& predicates = {}
     );
     WithPredicate<TypeId> checkExpr(const ScopePtr& scope, const AstExprBinary& expr, std::optional<TypeId> expectedType = std::nullopt);
-    WithPredicate<TypeId> checkExpr_DEPRECATED(const ScopePtr& scope, const AstExprBinary& expr, std::optional<TypeId> expectedType = std::nullopt);
     WithPredicate<TypeId> checkExpr(const ScopePtr& scope, const AstExprTypeAssertion& expr);
     WithPredicate<TypeId> checkExpr(const ScopePtr& scope, const AstExprError& expr);
     WithPredicate<TypeId> checkExpr(const ScopePtr& scope, const AstExprIfElse& expr, std::optional<TypeId> expectedType = std::nullopt);
@@ -487,7 +486,7 @@ private:
     /**
      * A set of incorrect class definitions which is used to avoid a second-pass analysis.
      */
-    DenseHashSet<const AstStatDeclareExternType*> incorrectExternTypeDefinitions{nullptr};
+    DenseHashSet<const AstStatDeclareClass*> incorrectClassDefinitions{nullptr};
 
     std::vector<std::pair<TypeId, ScopePtr>> deferredQuantification;
 };

Analysis/include/Luau/TypePack.h

@@ -1,12 +1,11 @@
 // This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
 #pragma once
 
-#include "Luau/Common.h"
-#include "Luau/NotNull.h"
-#include "Luau/Polarity.h"
-#include "Luau/TypeFwd.h"
 #include "Luau/Unifiable.h"
 #include "Luau/Variant.h"
+#include "Luau/TypeFwd.h"
+#include "Luau/NotNull.h"
+#include "Luau/Common.h"
 
 #include <optional>
 #include <set>
@@ -27,14 +26,12 @@ struct TypeFunctionInstanceTypePack;
 struct FreeTypePack
 {
     explicit FreeTypePack(TypeLevel level);
-    explicit FreeTypePack(Scope* scope, Polarity polarity = Polarity::Unknown);
+    explicit FreeTypePack(Scope* scope);
     FreeTypePack(Scope* scope, TypeLevel level);
 
     int index;
     TypeLevel level;
     Scope* scope = nullptr;
-
-    Polarity polarity = Polarity::Unknown;
 };
 
 struct GenericTypePack
@@ -43,7 +40,7 @@ struct GenericTypePack
     GenericTypePack();
     explicit GenericTypePack(TypeLevel level);
     explicit GenericTypePack(const Name& name);
-    explicit GenericTypePack(Scope* scope, Polarity polarity = Polarity::Unknown);
+    explicit GenericTypePack(Scope* scope);
     GenericTypePack(TypeLevel level, const Name& name);
     GenericTypePack(Scope* scope, const Name& name);
 
@@ -52,8 +49,6 @@ struct GenericTypePack
     Scope* scope = nullptr;
     Name name;
     bool explicitName = false;
-
-    Polarity polarity = Polarity::Unknown;
 };
 
 using BoundTypePack = Unifiable::Bound<TypePackId>;
@@ -105,9 +100,9 @@ struct TypeFunctionInstanceTypePack
 
 struct TypePackVar
 {
-    explicit TypePackVar(const TypePackVariant& tp);
+    explicit TypePackVar(const TypePackVariant& ty);
-    explicit TypePackVar(TypePackVariant&& tp);
+    explicit TypePackVar(TypePackVariant&& ty);
-    TypePackVar(TypePackVariant&& tp, bool persistent);
+    TypePackVar(TypePackVariant&& ty, bool persistent);
 
     bool operator==(const TypePackVar& rhs) const;
 
@@ -174,7 +169,6 @@ struct TypePackIterator
 
 private:
     TypePackId currentTypePack = nullptr;
-    TypePackId tailCycleCheck = nullptr;
     const TypePack* tp = nullptr;
     size_t currentIndex = 0;
 
@@ -185,8 +179,6 @@ TypePackIterator begin(TypePackId tp);
 TypePackIterator begin(TypePackId tp, const TxnLog* log);
 TypePackIterator end(TypePackId tp);
 
-TypePackId getTail(TypePackId tp);
-
 using SeenSet = std::set<std::pair<const void*, const void*>>;
 
 bool areEqual(SeenSet& seen, const TypePackVar& lhs, const TypePackVar& rhs);

Analysis/include/Luau/TypeUtils.h

@@ -289,6 +289,4 @@ std::vector<TypeId> findBlockedArgTypesIn(AstExprCall* expr, NotNull<DenseHashMa
  */
 void trackInteriorFreeType(Scope* scope, TypeId ty);
 
-void trackInteriorFreeTypePack(Scope* scope, TypePackId tp);
-
 } // namespace Luau

Analysis/include/Luau/Unifier.h

@@ -140,7 +140,7 @@ private:
     void tryUnifyTables(TypeId subTy, TypeId superTy, bool isIntersection = false, const LiteralProperties* aliasableMap = nullptr);
     void tryUnifyScalarShape(TypeId subTy, TypeId superTy, bool reversed);
     void tryUnifyWithMetatable(TypeId subTy, TypeId superTy, bool reversed);
-    void tryUnifyWithExternType(TypeId subTy, TypeId superTy, bool reversed);
+    void tryUnifyWithClass(TypeId subTy, TypeId superTy, bool reversed);
     void tryUnifyNegations(TypeId subTy, TypeId superTy);
 
     TypePackId tryApplyOverloadedFunction(TypeId function, const NormalizedFunctionType& overloads, TypePackId args);

Analysis/include/Luau/Unifier2.h

@@ -44,12 +44,6 @@ struct Unifier2
     // Mapping from generic type packs to `TypePack`s of free types to be used in instantiation.
     DenseHashMap<TypePackId, TypePackId> genericPackSubstitutions{nullptr};
 
-    // Unification sometimes results in the creation of new free types.
-    // We collect them here so that other systems can perform necessary
-    // bookkeeping.
-    std::vector<TypeId> newFreshTypes;
-    std::vector<TypePackId> newFreshTypePacks;
-
     int recursionCount = 0;
     int recursionLimit = 0;
 
@@ -119,9 +113,6 @@ private:
     // Returns true if needle occurs within haystack already.  ie if we bound
     // needle to haystack, would a cyclic TypePack result?
     OccursCheckResult occursCheck(DenseHashSet<TypePackId>& seen, TypePackId needle, TypePackId haystack);
-
-    TypeId freshType(NotNull<Scope> scope, Polarity polarity);
-    TypePackId freshTypePack(NotNull<Scope> scope, Polarity polarity);
 };
 
 } // namespace Luau

Analysis/include/Luau/VisitType.h

@@ -126,7 +126,7 @@ struct GenericTypeVisitor
     {
         return visit(ty);
     }
-    virtual bool visit(TypeId ty, const ExternType& etv)
+    virtual bool visit(TypeId ty, const ClassType& ctv)
     {
         return visit(ty);
     }
@@ -313,11 +313,11 @@ struct GenericTypeVisitor
                 traverse(mtv->metatable);
             }
         }
-        else if (auto etv = get<ExternType>(ty))
+        else if (auto ctv = get<ClassType>(ty))
         {
-            if (visit(ty, *etv))
+            if (visit(ty, *ctv))
             {
-                for (const auto& [name, prop] : etv->props)
+                for (const auto& [name, prop] : ctv->props)
                 {
                     if (FFlag::LuauSolverV2)
                     {
@@ -335,16 +335,16 @@ struct GenericTypeVisitor
                         traverse(prop.type());
                 }
 
-                if (etv->parent)
+                if (ctv->parent)
-                    traverse(*etv->parent);
+                    traverse(*ctv->parent);
 
-                if (etv->metatable)
+                if (ctv->metatable)
-                    traverse(*etv->metatable);
+                    traverse(*ctv->metatable);
 
-                if (etv->indexer)
+                if (ctv->indexer)
                 {
-                    traverse(etv->indexer->indexType);
+                    traverse(ctv->indexer->indexType);
-                    traverse(etv->indexer->indexResultType);
+                    traverse(ctv->indexer->indexResultType);
                 }
             }
         }
@@ -396,7 +396,7 @@ struct GenericTypeVisitor
                 traverse(unwrapped);
 
             // Visiting into LazyType that hasn't been unwrapped may necessarily cause infinite expansion, so we don't do that on purpose.
-            // Asserting also makes no sense, because the type _will_ happen here, most likely as a property of some ExternType
+            // Asserting also makes no sense, because the type _will_ happen here, most likely as a property of some ClassType
             // that doesn't need to be expanded.
         }
         else if (auto stv = get<SingletonType>(ty))

Analysis/src/AnyTypeSummary.cpp

@@ -0,0 +1,902 @@
+// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
+#include "Luau/AnyTypeSummary.h"
+
+#include "Luau/BuiltinDefinitions.h"
+#include "Luau/Clone.h"
+#include "Luau/Common.h"
+#include "Luau/Config.h"
+#include "Luau/ConstraintGenerator.h"
+#include "Luau/ConstraintSolver.h"
+#include "Luau/DataFlowGraph.h"
+#include "Luau/DcrLogger.h"
+#include "Luau/Module.h"
+#include "Luau/Parser.h"
+#include "Luau/Scope.h"
+#include "Luau/StringUtils.h"
+#include "Luau/TimeTrace.h"
+#include "Luau/ToString.h"
+#include "Luau/Transpiler.h"
+#include "Luau/TypeArena.h"
+#include "Luau/TypeChecker2.h"
+#include "Luau/NonStrictTypeChecker.h"
+#include "Luau/TypeInfer.h"
+#include "Luau/Variant.h"
+#include "Luau/VisitType.h"
+#include "Luau/TypePack.h"
+#include "Luau/TypeOrPack.h"
+
+#include <algorithm>
+#include <memory>
+#include <chrono>
+#include <condition_variable>
+#include <exception>
+#include <mutex>
+#include <stdexcept>
+#include <string>
+#include <iostream>
+
+
+#include <stdio.h>
+
+LUAU_FASTFLAGVARIABLE(StudioReportLuauAny2);
+LUAU_FASTINTVARIABLE(LuauAnySummaryRecursionLimit, 300);
+
+LUAU_FASTFLAG(DebugLuauMagicTypes);
+
+namespace Luau
+{
+
+void AnyTypeSummary::traverse(const Module* module, AstStat* src, NotNull<BuiltinTypes> builtinTypes)
+{
+    visit(findInnerMostScope(src->location, module), src, module, builtinTypes);
+}
+
+void AnyTypeSummary::visit(const Scope* scope, AstStat* stat, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    RecursionLimiter limiter{&recursionCount, FInt::LuauAnySummaryRecursionLimit};
+
+    if (auto s = stat->as<AstStatBlock>())
+        return visit(scope, s, module, builtinTypes);
+    else if (auto i = stat->as<AstStatIf>())
+        return visit(scope, i, module, builtinTypes);
+    else if (auto s = stat->as<AstStatWhile>())
+        return visit(scope, s, module, builtinTypes);
+    else if (auto s = stat->as<AstStatRepeat>())
+        return visit(scope, s, module, builtinTypes);
+    else if (auto r = stat->as<AstStatReturn>())
+        return visit(scope, r, module, builtinTypes);
+    else if (auto e = stat->as<AstStatExpr>())
+        return visit(scope, e, module, builtinTypes);
+    else if (auto s = stat->as<AstStatLocal>())
+        return visit(scope, s, module, builtinTypes);
+    else if (auto s = stat->as<AstStatFor>())
+        return visit(scope, s, module, builtinTypes);
+    else if (auto s = stat->as<AstStatForIn>())
+        return visit(scope, s, module, builtinTypes);
+    else if (auto a = stat->as<AstStatAssign>())
+        return visit(scope, a, module, builtinTypes);
+    else if (auto a = stat->as<AstStatCompoundAssign>())
+        return visit(scope, a, module, builtinTypes);
+    else if (auto f = stat->as<AstStatFunction>())
+        return visit(scope, f, module, builtinTypes);
+    else if (auto f = stat->as<AstStatLocalFunction>())
+        return visit(scope, f, module, builtinTypes);
+    else if (auto a = stat->as<AstStatTypeAlias>())
+        return visit(scope, a, module, builtinTypes);
+    else if (auto s = stat->as<AstStatDeclareGlobal>())
+        return visit(scope, s, module, builtinTypes);
+    else if (auto s = stat->as<AstStatDeclareFunction>())
+        return visit(scope, s, module, builtinTypes);
+    else if (auto s = stat->as<AstStatDeclareClass>())
+        return visit(scope, s, module, builtinTypes);
+    else if (auto s = stat->as<AstStatError>())
+        return visit(scope, s, module, builtinTypes);
+}
+
+void AnyTypeSummary::visit(const Scope* scope, AstStatBlock* block, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    RecursionCounter counter{&recursionCount};
+
+    if (recursionCount >= FInt::LuauAnySummaryRecursionLimit)
+        return; // don't report
+
+    for (AstStat* stat : block->body)
+        visit(scope, stat, module, builtinTypes);
+}
+
+void AnyTypeSummary::visit(const Scope* scope, AstStatIf* ifStatement, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    if (ifStatement->thenbody)
+    {
+        const Scope* thenScope = findInnerMostScope(ifStatement->thenbody->location, module);
+        visit(thenScope, ifStatement->thenbody, module, builtinTypes);
+    }
+
+    if (ifStatement->elsebody)
+    {
+        const Scope* elseScope = findInnerMostScope(ifStatement->elsebody->location, module);
+        visit(elseScope, ifStatement->elsebody, module, builtinTypes);
+    }
+}
+
+void AnyTypeSummary::visit(const Scope* scope, AstStatWhile* while_, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    const Scope* whileScope = findInnerMostScope(while_->location, module);
+    visit(whileScope, while_->body, module, builtinTypes);
+}
+
+void AnyTypeSummary::visit(const Scope* scope, AstStatRepeat* repeat, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    const Scope* repeatScope = findInnerMostScope(repeat->location, module);
+    visit(repeatScope, repeat->body, module, builtinTypes);
+}
+
+void AnyTypeSummary::visit(const Scope* scope, AstStatReturn* ret, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    const Scope* retScope = findInnerMostScope(ret->location, module);
+
+    auto ctxNode = getNode(rootSrc, ret);
+    bool seenTP = false;
+
+    for (auto val : ret->list)
+    {
+        if (isAnyCall(retScope, val, module, builtinTypes))
+        {
+            TelemetryTypePair types;
+            types.inferredType = toString(lookupType(val, module, builtinTypes));
+            TypeInfo ti{Pattern::FuncApp, toString(ctxNode), types};
+            typeInfo.push_back(ti);
+        }
+
+        if (isAnyCast(retScope, val, module, builtinTypes))
+        {
+            if (auto cast = val->as<AstExprTypeAssertion>())
+            {
+                TelemetryTypePair types;
+
+                types.annotatedType = toString(lookupAnnotation(cast->annotation, module, builtinTypes));
+                types.inferredType = toString(lookupType(cast->expr, module, builtinTypes));
+
+                TypeInfo ti{Pattern::Casts, toString(ctxNode), types};
+                typeInfo.push_back(ti);
+            }
+        }
+
+        if (ret->list.size > 1 && !seenTP)
+        {
+            if (containsAny(retScope->returnType))
+            {
+                seenTP = true;
+
+                TelemetryTypePair types;
+
+                types.inferredType = toString(retScope->returnType);
+
+                TypeInfo ti{Pattern::TypePk, toString(ctxNode), types};
+                typeInfo.push_back(ti);
+            }
+        }
+    }
+}
+
+void AnyTypeSummary::visit(const Scope* scope, AstStatLocal* local, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    auto ctxNode = getNode(rootSrc, local);
+
+    TypePackId values = reconstructTypePack(local->values, module, builtinTypes);
+    auto [head, tail] = flatten(values);
+
+    size_t posn = 0;
+    for (AstLocal* loc : local->vars)
+    {
+        if (local->vars.data[0] == loc && posn < local->values.size)
+        {
+            if (loc->annotation)
+            {
+                auto annot = lookupAnnotation(loc->annotation, module, builtinTypes);
+                if (containsAny(annot))
+                {
+                    TelemetryTypePair types;
+
+                    types.annotatedType = toString(annot);
+                    types.inferredType = toString(lookupType(local->values.data[posn], module, builtinTypes));
+
+                    TypeInfo ti{Pattern::VarAnnot, toString(ctxNode), types};
+                    typeInfo.push_back(ti);
+                }
+            }
+
+            const AstExprTypeAssertion* maybeRequire = local->values.data[posn]->as<AstExprTypeAssertion>();
+            if (!maybeRequire)
+                continue;
+
+            if (std::min(local->values.size - 1, posn) < head.size())
+            {
+                if (isAnyCast(scope, local->values.data[posn], module, builtinTypes))
+                {
+                    TelemetryTypePair types;
+
+                    types.inferredType = toString(head[std::min(local->values.size - 1, posn)]);
+
+                    TypeInfo ti{Pattern::Casts, toString(ctxNode), types};
+                    typeInfo.push_back(ti);
+                }
+            }
+        }
+        else
+        {
+
+            if (std::min(local->values.size - 1, posn) < head.size())
+            {
+                if (loc->annotation)
+                {
+                    auto annot = lookupAnnotation(loc->annotation, module, builtinTypes);
+                    if (containsAny(annot))
+                    {
+                        TelemetryTypePair types;
+
+                        types.annotatedType = toString(annot);
+                        types.inferredType = toString(head[std::min(local->values.size - 1, posn)]);
+
+                        TypeInfo ti{Pattern::VarAnnot, toString(ctxNode), types};
+                        typeInfo.push_back(ti);
+                    }
+                }
+            }
+            else
+            {
+                if (tail)
+                {
+                    if (containsAny(*tail))
+                    {
+                        TelemetryTypePair types;
+
+                        types.inferredType = toString(*tail);
+
+                        TypeInfo ti{Pattern::VarAny, toString(ctxNode), types};
+                        typeInfo.push_back(ti);
+                    }
+                }
+            }
+        }
+
+        ++posn;
+    }
+}
+
+void AnyTypeSummary::visit(const Scope* scope, AstStatFor* for_, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    const Scope* forScope = findInnerMostScope(for_->location, module);
+    visit(forScope, for_->body, module, builtinTypes);
+}
+
+void AnyTypeSummary::visit(const Scope* scope, AstStatForIn* forIn, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    const Scope* loopScope = findInnerMostScope(forIn->location, module);
+    visit(loopScope, forIn->body, module, builtinTypes);
+}
+
+void AnyTypeSummary::visit(const Scope* scope, AstStatAssign* assign, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    auto ctxNode = getNode(rootSrc, assign);
+
+    TypePackId values = reconstructTypePack(assign->values, module, builtinTypes);
+    auto [head, tail] = flatten(values);
+
+    size_t posn = 0;
+    for (AstExpr* var : assign->vars)
+    {
+        TypeId tp = lookupType(var, module, builtinTypes);
+        if (containsAny(tp))
+        {
+            TelemetryTypePair types;
+
+            types.annotatedType = toString(tp);
+
+            auto loc = std::min(assign->vars.size - 1, posn);
+            if (head.size() >= assign->vars.size && posn < head.size())
+            {
+                types.inferredType = toString(head[posn]);
+            }
+            else if (loc < head.size())
+                types.inferredType = toString(head[loc]);
+            else
+                types.inferredType = toString(builtinTypes->nilType);
+
+            TypeInfo ti{Pattern::Assign, toString(ctxNode), types};
+            typeInfo.push_back(ti);
+        }
+        ++posn;
+    }
+
+    for (AstExpr* val : assign->values)
+    {
+        if (isAnyCall(scope, val, module, builtinTypes))
+        {
+            TelemetryTypePair types;
+
+            types.inferredType = toString(lookupType(val, module, builtinTypes));
+
+            TypeInfo ti{Pattern::FuncApp, toString(ctxNode), types};
+            typeInfo.push_back(ti);
+        }
+
+        if (isAnyCast(scope, val, module, builtinTypes))
+        {
+            if (auto cast = val->as<AstExprTypeAssertion>())
+            {
+                TelemetryTypePair types;
+
+                types.annotatedType = toString(lookupAnnotation(cast->annotation, module, builtinTypes));
+                types.inferredType = toString(lookupType(val, module, builtinTypes));
+
+                TypeInfo ti{Pattern::Casts, toString(ctxNode), types};
+                typeInfo.push_back(ti);
+            }
+        }
+    }
+
+    if (tail)
+    {
+        if (containsAny(*tail))
+        {
+            TelemetryTypePair types;
+
+            types.inferredType = toString(*tail);
+
+            TypeInfo ti{Pattern::Assign, toString(ctxNode), types};
+            typeInfo.push_back(ti);
+        }
+    }
+}
+
+void AnyTypeSummary::visit(const Scope* scope, AstStatCompoundAssign* assign, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    auto ctxNode = getNode(rootSrc, assign);
+
+    TelemetryTypePair types;
+
+    types.inferredType = toString(lookupType(assign->value, module, builtinTypes));
+    types.annotatedType = toString(lookupType(assign->var, module, builtinTypes));
+
+    if (module->astTypes.contains(assign->var))
+    {
+        if (containsAny(*module->astTypes.find(assign->var)))
+        {
+            TypeInfo ti{Pattern::Assign, toString(ctxNode), types};
+            typeInfo.push_back(ti);
+        }
+    }
+    else if (module->astTypePacks.contains(assign->var))
+    {
+        if (containsAny(*module->astTypePacks.find(assign->var)))
+        {
+            TypeInfo ti{Pattern::Assign, toString(ctxNode), types};
+            typeInfo.push_back(ti);
+        }
+    }
+
+    if (isAnyCall(scope, assign->value, module, builtinTypes))
+    {
+        TypeInfo ti{Pattern::FuncApp, toString(ctxNode), types};
+        typeInfo.push_back(ti);
+    }
+
+    if (isAnyCast(scope, assign->value, module, builtinTypes))
+    {
+        if (auto cast = assign->value->as<AstExprTypeAssertion>())
+        {
+            types.annotatedType = toString(lookupAnnotation(cast->annotation, module, builtinTypes));
+            types.inferredType = toString(lookupType(cast->expr, module, builtinTypes));
+
+            TypeInfo ti{Pattern::Casts, toString(ctxNode), types};
+            typeInfo.push_back(ti);
+        }
+    }
+}
+
+void AnyTypeSummary::visit(const Scope* scope, AstStatFunction* function, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    TelemetryTypePair types;
+    types.inferredType = toString(lookupType(function->func, module, builtinTypes));
+
+    if (hasVariadicAnys(scope, function->func, module, builtinTypes))
+    {
+        TypeInfo ti{Pattern::VarAny, toString(function), types};
+        typeInfo.push_back(ti);
+    }
+
+    if (hasArgAnys(scope, function->func, module, builtinTypes))
+    {
+        TypeInfo ti{Pattern::FuncArg, toString(function), types};
+        typeInfo.push_back(ti);
+    }
+
+    if (hasAnyReturns(scope, function->func, module, builtinTypes))
+    {
+        TypeInfo ti{Pattern::FuncRet, toString(function), types};
+        typeInfo.push_back(ti);
+    }
+
+    if (function->func->body->body.size > 0)
+        visit(scope, function->func->body, module, builtinTypes);
+}
+
+void AnyTypeSummary::visit(const Scope* scope, AstStatLocalFunction* function, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    TelemetryTypePair types;
+
+    if (hasVariadicAnys(scope, function->func, module, builtinTypes))
+    {
+        types.inferredType = toString(lookupType(function->func, module, builtinTypes));
+        TypeInfo ti{Pattern::VarAny, toString(function), types};
+        typeInfo.push_back(ti);
+    }
+
+    if (hasArgAnys(scope, function->func, module, builtinTypes))
+    {
+        types.inferredType = toString(lookupType(function->func, module, builtinTypes));
+        TypeInfo ti{Pattern::FuncArg, toString(function), types};
+        typeInfo.push_back(ti);
+    }
+
+    if (hasAnyReturns(scope, function->func, module, builtinTypes))
+    {
+        types.inferredType = toString(lookupType(function->func, module, builtinTypes));
+        TypeInfo ti{Pattern::FuncRet, toString(function), types};
+        typeInfo.push_back(ti);
+    }
+
+    if (function->func->body->body.size > 0)
+        visit(scope, function->func->body, module, builtinTypes);
+}
+
+void AnyTypeSummary::visit(const Scope* scope, AstStatTypeAlias* alias, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    auto ctxNode = getNode(rootSrc, alias);
+
+    auto annot = lookupAnnotation(alias->type, module, builtinTypes);
+    if (containsAny(annot))
+    {
+        // no expr => no inference for aliases
+        TelemetryTypePair types;
+
+        types.annotatedType = toString(annot);
+        TypeInfo ti{Pattern::Alias, toString(ctxNode), types};
+        typeInfo.push_back(ti);
+    }
+}
+
+void AnyTypeSummary::visit(const Scope* scope, AstStatExpr* expr, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    auto ctxNode = getNode(rootSrc, expr);
+
+    if (isAnyCall(scope, expr->expr, module, builtinTypes))
+    {
+        TelemetryTypePair types;
+        types.inferredType = toString(lookupType(expr->expr, module, builtinTypes));
+
+        TypeInfo ti{Pattern::FuncApp, toString(ctxNode), types};
+        typeInfo.push_back(ti);
+    }
+}
+
+void AnyTypeSummary::visit(const Scope* scope, AstStatDeclareGlobal* declareGlobal, const Module* module, NotNull<BuiltinTypes> builtinTypes) {}
+
+void AnyTypeSummary::visit(const Scope* scope, AstStatDeclareClass* declareClass, const Module* module, NotNull<BuiltinTypes> builtinTypes) {}
+
+void AnyTypeSummary::visit(const Scope* scope, AstStatDeclareFunction* declareFunction, const Module* module, NotNull<BuiltinTypes> builtinTypes) {}
+
+void AnyTypeSummary::visit(const Scope* scope, AstStatError* error, const Module* module, NotNull<BuiltinTypes> builtinTypes) {}
+
+TypeId AnyTypeSummary::checkForFamilyInhabitance(const TypeId instance, const Location location)
+{
+    if (seenTypeFamilyInstances.find(instance))
+        return instance;
+
+    seenTypeFamilyInstances.insert(instance);
+    return instance;
+}
+
+TypeId AnyTypeSummary::lookupType(const AstExpr* expr, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    const TypeId* ty = module->astTypes.find(expr);
+    if (ty)
+        return checkForFamilyInhabitance(follow(*ty), expr->location);
+
+    const TypePackId* tp = module->astTypePacks.find(expr);
+    if (tp)
+    {
+        if (auto fst = first(*tp, /*ignoreHiddenVariadics*/ false))
+            return checkForFamilyInhabitance(*fst, expr->location);
+        else if (finite(*tp) && size(*tp) == 0)
+            return checkForFamilyInhabitance(builtinTypes->nilType, expr->location);
+    }
+
+    return builtinTypes->errorRecoveryType();
+}
+
+TypePackId AnyTypeSummary::reconstructTypePack(AstArray<AstExpr*> exprs, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    if (exprs.size == 0)
+        return arena.addTypePack(TypePack{{}, std::nullopt});
+
+    std::vector<TypeId> head;
+
+    for (size_t i = 0; i < exprs.size - 1; ++i)
+    {
+        head.push_back(lookupType(exprs.data[i], module, builtinTypes));
+    }
+
+    const TypePackId* tail = module->astTypePacks.find(exprs.data[exprs.size - 1]);
+    if (tail)
+        return arena.addTypePack(TypePack{std::move(head), follow(*tail)});
+    else
+        return arena.addTypePack(TypePack{std::move(head), builtinTypes->errorRecoveryTypePack()});
+}
+
+bool AnyTypeSummary::isAnyCall(const Scope* scope, AstExpr* expr, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    if (auto call = expr->as<AstExprCall>())
+    {
+        TypePackId args = reconstructTypePack(call->args, module, builtinTypes);
+        if (containsAny(args))
+            return true;
+
+        TypeId func = lookupType(call->func, module, builtinTypes);
+        if (containsAny(func))
+            return true;
+    }
+    return false;
+}
+
+bool AnyTypeSummary::hasVariadicAnys(const Scope* scope, AstExprFunction* expr, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    if (expr->vararg && expr->varargAnnotation)
+    {
+        auto annot = lookupPackAnnotation(expr->varargAnnotation, module);
+        if (annot && containsAny(*annot))
+        {
+            return true;
+        }
+    }
+    return false;
+}
+
+bool AnyTypeSummary::hasArgAnys(const Scope* scope, AstExprFunction* expr, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    if (expr->args.size > 0)
+    {
+        for (const AstLocal* arg : expr->args)
+        {
+            if (arg->annotation)
+            {
+                auto annot = lookupAnnotation(arg->annotation, module, builtinTypes);
+                if (containsAny(annot))
+                {
+                    return true;
+                }
+            }
+        }
+    }
+    return false;
+}
+
+bool AnyTypeSummary::hasAnyReturns(const Scope* scope, AstExprFunction* expr, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    if (!expr->returnAnnotation)
+    {
+        return false;
+    }
+
+    for (AstType* ret : expr->returnAnnotation->types)
+    {
+        if (containsAny(lookupAnnotation(ret, module, builtinTypes)))
+        {
+            return true;
+        }
+    }
+
+    if (expr->returnAnnotation->tailType)
+    {
+        auto annot = lookupPackAnnotation(expr->returnAnnotation->tailType, module);
+        if (annot && containsAny(*annot))
+        {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+bool AnyTypeSummary::isAnyCast(const Scope* scope, AstExpr* expr, const Module* module, NotNull<BuiltinTypes> builtinTypes)
+{
+    if (auto cast = expr->as<AstExprTypeAssertion>())
+    {
+        auto annot = lookupAnnotation(cast->annotation, module, builtinTypes);
+        if (containsAny(annot))
+        {
+            return true;
+        }
+    }
+    return false;
+}
+
+TypeId AnyTypeSummary::lookupAnnotation(AstType* annotation, const Module* module, NotNull<BuiltinTypes> builtintypes)
+{
+    if (FFlag::DebugLuauMagicTypes)
+    {
+        if (auto ref = annotation->as<AstTypeReference>(); ref && ref->parameters.size > 0)
+        {
+            if (auto ann = ref->parameters.data[0].type)
+            {
+                TypeId argTy = lookupAnnotation(ref->parameters.data[0].type, module, builtintypes);
+                return follow(argTy);
+            }
+        }
+    }
+
+    const TypeId* ty = module->astResolvedTypes.find(annotation);
+    if (ty)
+        return checkForTypeFunctionInhabitance(follow(*ty), annotation->location);
+    else
+        return checkForTypeFunctionInhabitance(builtintypes->errorRecoveryType(), annotation->location);
+}
+
+TypeId AnyTypeSummary::checkForTypeFunctionInhabitance(const TypeId instance, const Location location)
+{
+    if (seenTypeFunctionInstances.find(instance))
+        return instance;
+    seenTypeFunctionInstances.insert(instance);
+
+    return instance;
+}
+
+std::optional<TypePackId> AnyTypeSummary::lookupPackAnnotation(AstTypePack* annotation, const Module* module)
+{
+    const TypePackId* tp = module->astResolvedTypePacks.find(annotation);
+    if (tp != nullptr)
+        return {follow(*tp)};
+    return {};
+}
+
+bool AnyTypeSummary::containsAny(TypeId typ)
+{
+    typ = follow(typ);
+
+    if (auto t = seen.find(typ); t && !*t)
+    {
+        return false;
+    }
+
+    seen[typ] = false;
+
+    RecursionCounter counter{&recursionCount};
+    if (recursionCount >= FInt::LuauAnySummaryRecursionLimit)
+    {
+        return false;
+    }
+
+    bool found = false;
+
+    if (auto ty = get<AnyType>(typ))
+    {
+        found = true;
+    }
+    else if (auto ty = get<UnknownType>(typ))
+    {
+        found = true;
+    }
+    else if (auto ty = get<TableType>(typ))
+    {
+        for (auto& [_name, prop] : ty->props)
+        {
+            if (FFlag::LuauSolverV2)
+            {
+                if (auto newT = follow(prop.readTy))
+                {
+                    if (containsAny(*newT))
+                        found = true;
+                }
+                else if (auto newT = follow(prop.writeTy))
+                {
+                    if (containsAny(*newT))
+                        found = true;
+                }
+            }
+            else
+            {
+                if (containsAny(prop.type()))
+                    found = true;
+            }
+        }
+    }
+    else if (auto ty = get<IntersectionType>(typ))
+    {
+        for (auto part : ty->parts)
+        {
+            if (containsAny(part))
+            {
+                found = true;
+            }
+        }
+    }
+    else if (auto ty = get<UnionType>(typ))
+    {
+        for (auto option : ty->options)
+        {
+            if (containsAny(option))
+            {
+                found = true;
+            }
+        }
+    }
+    else if (auto ty = get<FunctionType>(typ))
+    {
+        if (containsAny(ty->argTypes))
+            found = true;
+        else if (containsAny(ty->retTypes))
+            found = true;
+    }
+
+    seen[typ] = found;
+
+    return found;
+}
+
+bool AnyTypeSummary::containsAny(TypePackId typ)
+{
+    typ = follow(typ);
+
+    if (auto t = seen.find(typ); t && !*t)
+    {
+        return false;
+    }
+
+    seen[typ] = false;
+
+    auto [head, tail] = flatten(typ);
+    bool found = false;
+
+    for (auto tp : head)
+    {
+        if (containsAny(tp))
+            found = true;
+    }
+
+    if (tail)
+    {
+        if (auto vtp = get<VariadicTypePack>(tail))
+        {
+            if (auto ty = get<AnyType>(follow(vtp->ty)))
+            {
+                found = true;
+            }
+        }
+        else if (auto tftp = get<TypeFunctionInstanceTypePack>(tail))
+        {
+
+            for (TypePackId tp : tftp->packArguments)
+            {
+                if (containsAny(tp))
+                {
+                    found = true;
+                }
+            }
+
+            for (TypeId t : tftp->typeArguments)
+            {
+                if (containsAny(t))
+                {
+                    found = true;
+                }
+            }
+        }
+    }
+
+    seen[typ] = found;
+
+    return found;
+}
+
+const Scope* AnyTypeSummary::findInnerMostScope(const Location location, const Module* module)
+{
+    const Scope* bestScope = module->getModuleScope().get();
+
+    bool didNarrow = false;
+    do
+    {
+        didNarrow = false;
+        for (auto scope : bestScope->children)
+        {
+            if (scope->location.encloses(location))
+            {
+                bestScope = scope.get();
+                didNarrow = true;
+                break;
+            }
+        }
+    } while (didNarrow && bestScope->children.size() > 0);
+
+    return bestScope;
+}
+
+std::optional<AstExpr*> AnyTypeSummary::matchRequire(const AstExprCall& call)
+{
+    const char* require = "require";
+
+    if (call.args.size != 1)
+        return std::nullopt;
+
+    const AstExprGlobal* funcAsGlobal = call.func->as<AstExprGlobal>();
+    if (!funcAsGlobal || funcAsGlobal->name != require)
+        return std::nullopt;
+
+    if (call.args.size != 1)
+        return std::nullopt;
+
+    return call.args.data[0];
+}
+
+AstNode* AnyTypeSummary::getNode(AstStatBlock* root, AstNode* node)
+{
+    FindReturnAncestry finder(node, root->location.end);
+    root->visit(&finder);
+
+    if (!finder.currNode)
+        finder.currNode = node;
+
+    LUAU_ASSERT(finder.found && finder.currNode);
+    return finder.currNode;
+}
+
+bool AnyTypeSummary::FindReturnAncestry::visit(AstStatLocalFunction* node)
+{
+    currNode = node;
+    return !found;
+}
+
+bool AnyTypeSummary::FindReturnAncestry::visit(AstStatFunction* node)
+{
+    currNode = node;
+    return !found;
+}
+
+bool AnyTypeSummary::FindReturnAncestry::visit(AstType* node)
+{
+    return !found;
+}
+
+bool AnyTypeSummary::FindReturnAncestry::visit(AstNode* node)
+{
+    if (node == stat)
+    {
+        found = true;
+    }
+
+    if (node->location.end == rootEnd && stat->location.end >= rootEnd)
+    {
+        currNode = node;
+        found = true;
+    }
+
+    return !found;
+}
+
+
+AnyTypeSummary::TypeInfo::TypeInfo(Pattern code, std::string node, TelemetryTypePair type)
+    : code(code)
+    , node(node)
+    , type(type)
+{
+}
+
+AnyTypeSummary::FindReturnAncestry::FindReturnAncestry(AstNode* stat, Position rootEnd)
+    : stat(stat)
+    , rootEnd(rootEnd)
+{
+}
+
+AnyTypeSummary::AnyTypeSummary() {}
+
+} // namespace Luau

Analysis/src/Anyification.cpp

@@ -88,7 +88,7 @@ TypePackId Anyification::clean(TypePackId tp)
 
 bool Anyification::ignoreChildren(TypeId ty)
 {
-    if (get<ExternType>(ty))
+    if (get<ClassType>(ty))
         return true;
 
     return ty->persistent;

Analysis/src/ApplyTypeFunction.cpp

@@ -31,7 +31,7 @@ bool ApplyTypeFunction::ignoreChildren(TypeId ty)
 {
     if (get<GenericType>(ty))
         return true;
-    else if (get<ExternType>(ty))
+    else if (get<ClassType>(ty))
         return true;
     else
         return false;

Analysis/src/AstJsonEncoder.cpp

@@ -8,8 +8,6 @@
 
 #include <math.h>
 
-LUAU_FASTFLAG(LuauStoreReturnTypesAsPackOnAst)
-
 namespace Luau
 {
 
@@ -433,16 +431,8 @@ struct AstJsonEncoder : public AstVisitor
                 if (node->self)
                     PROP(self);
                 PROP(args);
-                if (FFlag::LuauStoreReturnTypesAsPackOnAst)
-                {
                 if (node->returnAnnotation)
                     PROP(returnAnnotation);
-                }
-                else
-                {
-                    if (node->returnAnnotation_DEPRECATED)
-                        write("returnAnnotation", node->returnAnnotation_DEPRECATED);
-                }
                 PROP(vararg);
                 PROP(varargLocation);
                 if (node->varargAnnotation)
@@ -475,26 +465,26 @@ struct AstJsonEncoder : public AstVisitor
         writeRaw("}");
     }
 
-    void write(class AstGenericType* genericType)
+    void write(const AstGenericType& genericType)
     {
         writeRaw("{");
         bool c = pushComma();
         writeType("AstGenericType");
-        write("name", genericType->name);
+        write("name", genericType.name);
-        if (genericType->defaultValue)
+        if (genericType.defaultValue)
-            write("luauType", genericType->defaultValue);
+            write("luauType", genericType.defaultValue);
         popComma(c);
         writeRaw("}");
     }
 
-    void write(class AstGenericTypePack* genericTypePack)
+    void write(const AstGenericTypePack& genericTypePack)
     {
         writeRaw("{");
         bool c = pushComma();
         writeType("AstGenericTypePack");
-        write("name", genericTypePack->name);
+        write("name", genericTypePack.name);
-        if (genericTypePack->defaultValue)
+        if (genericTypePack.defaultValue)
-            write("luauType", genericTypePack->defaultValue);
+            write("luauType", genericTypePack.defaultValue);
         popComma(c);
         writeRaw("}");
     }
@@ -912,10 +902,7 @@ struct AstJsonEncoder : public AstVisitor
                 PROP(paramNames);
                 PROP(vararg);
                 PROP(varargLocation);
-                if (FFlag::LuauStoreReturnTypesAsPackOnAst)
                 PROP(retTypes);
-                else
-                    write("retTypes", node->retTypes_DEPRECATED);
                 PROP(generics);
                 PROP(genericPacks);
             }
@@ -936,7 +923,7 @@ struct AstJsonEncoder : public AstVisitor
         );
     }
 
-    void write(const AstDeclaredExternTypeProperty& prop)
+    void write(const AstDeclaredClassProp& prop)
     {
         writeRaw("{");
         bool c = pushComma();
@@ -949,7 +936,7 @@ struct AstJsonEncoder : public AstVisitor
         writeRaw("}");
     }
 
-    void write(class AstStatDeclareExternType* node)
+    void write(class AstStatDeclareClass* node)
     {
         writeNode(
             node,
@@ -1061,10 +1048,7 @@ struct AstJsonEncoder : public AstVisitor
                 PROP(genericPacks);
                 PROP(argTypes);
                 PROP(argNames);
-                if (FFlag::LuauStoreReturnTypesAsPackOnAst)
                 PROP(returnTypes);
-                else
-                    write("returnTypes", node->returnTypes_DEPRECATED);
             }
         );
     }
@@ -1167,8 +1151,6 @@ struct AstJsonEncoder : public AstVisitor
             return writeString("checked");
         case AstAttr::Type::Native:
             return writeString("native");
-        case AstAttr::Type::Deprecated:
-            return writeString("deprecated");
         }
     }
 
@@ -1445,7 +1427,7 @@ struct AstJsonEncoder : public AstVisitor
         return false;
     }
 
-    bool visit(class AstStatDeclareExternType* node) override
+    bool visit(class AstStatDeclareClass* node) override
     {
         write(node);
         return false;

Analysis/src/AstQuery.cpp

@@ -13,6 +13,8 @@
 
 LUAU_FASTFLAG(LuauSolverV2)
 
+LUAU_FASTFLAG(LuauExtendStatEndPosWithSemicolon)
+
 namespace Luau
 {
 
@@ -40,6 +42,8 @@ struct AutocompleteNodeFinder : public AstVisitor
     }
 
     bool visit(AstStat* stat) override
+    {
+        if (FFlag::LuauExtendStatEndPosWithSemicolon)
         {
             // Consider 'local myLocal = 4;|' and 'local myLocal = 4', where '|' is the cursor position. In both cases, the cursor position is equal
             // to `AstStatLocal.location.end`. However, in the first case (semicolon), we are starting a new statement, whilst in the second case
@@ -49,6 +53,15 @@ struct AutocompleteNodeFinder : public AstVisitor
                 ancestry.push_back(stat);
                 return true;
             }
+        }
+        else
+        {
+            if (stat->location.begin < pos && pos <= stat->location.end)
+            {
+                ancestry.push_back(stat);
+                return true;
+            }
+        }
 
         return false;
     }
@@ -574,11 +587,11 @@ std::optional<DocumentationSymbol> getDocumentationSymbolAtPosition(const Source
                             return checkOverloadedDocumentationSymbol(module, propIt->second.type(), parentExpr, propIt->second.documentationSymbol);
                     }
                 }
-                else if (const ExternType* etv = get<ExternType>(parentTy))
+                else if (const ClassType* ctv = get<ClassType>(parentTy))
                 {
-                    while (etv)
+                    while (ctv)
                     {
-                        if (auto propIt = etv->props.find(indexName->index.value); propIt != etv->props.end())
+                        if (auto propIt = ctv->props.find(indexName->index.value); propIt != ctv->props.end())
                         {
                             if (FFlag::LuauSolverV2)
                             {
@@ -590,7 +603,7 @@ std::optional<DocumentationSymbol> getDocumentationSymbolAtPosition(const Source
                                     module, propIt->second.type(), parentExpr, propIt->second.documentationSymbol
                                 );
                         }
-                        etv = etv->parent ? Luau::get<Luau::ExternType>(*etv->parent) : nullptr;
+                        ctv = ctv->parent ? Luau::get<Luau::ClassType>(*ctv->parent) : nullptr;
                     }
                 }
                 else if (const PrimitiveType* ptv = get<PrimitiveType>(parentTy); ptv && ptv->metatable)

Analysis/src/AutocompleteCore.cpp

@@ -24,10 +24,13 @@ LUAU_FASTFLAG(LuauSolverV2)
 LUAU_FASTINT(LuauTypeInferIterationLimit)
 LUAU_FASTINT(LuauTypeInferRecursionLimit)
 LUAU_FASTFLAGVARIABLE(DebugLuauMagicVariableNames)
+
+LUAU_FASTFLAG(LuauExposeRequireByStringAutocomplete)
+
+LUAU_FASTFLAGVARIABLE(LuauAutocompleteRefactorsForIncrementalAutocomplete)
+
 LUAU_FASTFLAGVARIABLE(LuauAutocompleteUsesModuleForTypeCompatibility)
 LUAU_FASTFLAGVARIABLE(LuauAutocompleteUnionCopyPreviousSeen)
-LUAU_FASTFLAGVARIABLE(LuauAutocompleteMissingFollows)
-LUAU_FASTFLAG(LuauStoreReturnTypesAsPackOnAst)
 
 static const std::unordered_set<std::string> kStatementStartingKeywords =
     {"while", "if", "local", "repeat", "function", "do", "for", "return", "break", "continue", "type", "export"};
@@ -80,8 +83,6 @@ static ParenthesesRecommendation getParenRecommendationForIntersect(const Inters
     ParenthesesRecommendation rec = ParenthesesRecommendation::None;
     for (Luau::TypeId partId : intersect->parts)
     {
-        if (FFlag::LuauAutocompleteMissingFollows)
-            partId = follow(partId);
         if (auto partFunc = Luau::get<FunctionType>(partId))
         {
             rec = std::max(rec, getParenRecommendationForFunc(partFunc, nodes));
@@ -307,7 +308,7 @@ static void autocompleteProps(
     const std::vector<AstNode*>& nodes,
     AutocompleteEntryMap& result,
     std::unordered_set<TypeId>& seen,
-    std::optional<const ExternType*> containingExternType = std::nullopt
+    std::optional<const ClassType*> containingClass = std::nullopt
 )
 {
     rootTy = follow(rootTy);
@@ -330,8 +331,8 @@ static void autocompleteProps(
             if (calledWithSelf == ftv->hasSelf)
                 return true;
 
-            // Calls on extern types require strict match between how function is declared and how it's called
+            // Calls on classes require strict match between how function is declared and how it's called
-            if (get<ExternType>(rootTy))
+            if (get<ClassType>(rootTy))
                 return false;
 
             // When called with ':', but declared without 'self', it is invalid if a function has incompatible first argument or no arguments at all
@@ -364,7 +365,7 @@ static void autocompleteProps(
         return calledWithSelf;
     };
 
-    auto fillProps = [&](const ExternType::Props& props)
+    auto fillProps = [&](const ClassType::Props& props)
     {
         for (const auto& [name, prop] : props)
         {
@@ -397,7 +398,7 @@ static void autocompleteProps(
                     prop.deprecated,
                     isWrongIndexer(type),
                     typeCorrect,
-                    containingExternType,
+                    containingClass,
                     &prop,
                     prop.documentationSymbol,
                     {},
@@ -428,12 +429,12 @@ static void autocompleteProps(
         }
     };
 
-    if (auto cls = get<ExternType>(ty))
+    if (auto cls = get<ClassType>(ty))
     {
-        containingExternType = containingExternType.value_or(cls);
+        containingClass = containingClass.value_or(cls);
         fillProps(cls->props);
         if (cls->parent)
-            autocompleteProps(module, typeArena, builtinTypes, rootTy, *cls->parent, indexType, nodes, result, seen, containingExternType);
+            autocompleteProps(module, typeArena, builtinTypes, rootTy, *cls->parent, indexType, nodes, result, seen, containingClass);
     }
     else if (auto tbl = get<TableType>(ty))
         fillProps(tbl->props);
@@ -487,12 +488,12 @@ static void autocompleteProps(
             // If we don't do this, and we have the misfortune of receiving a
             // recursive union like:
             //
-            //  t1 where t1 = t1 | ExternType
+            //  t1 where t1 = t1 | Class
             //
             // Then we are on a one way journey to a stack overflow.
             if (FFlag::LuauAutocompleteUnionCopyPreviousSeen)
             {
-                for (auto ty : seen)
+                for (auto ty: seen)
                 {
                     if (is<UnionType, IntersectionType>(ty))
                         innerSeen.insert(ty);
@@ -587,7 +588,7 @@ AutocompleteEntryMap autocompleteProps(
 AutocompleteEntryMap autocompleteModuleTypes(const Module& module, const ScopePtr& scopeAtPosition, Position position, std::string_view moduleName)
 {
     AutocompleteEntryMap result;
-    ScopePtr startScope = scopeAtPosition;
+    ScopePtr startScope = FFlag::LuauAutocompleteRefactorsForIncrementalAutocomplete ? scopeAtPosition : findScopeAtPosition(module, position);
     for (ScopePtr& scope = startScope; scope; scope = scope->parent)
     {
         if (auto it = scope->importedTypeBindings.find(std::string(moduleName)); it != scope->importedTypeBindings.end())
@@ -699,30 +700,6 @@ static std::optional<TypeId> findTypeElementAt(const AstTypeList& astTypeList, T
     return {};
 }
 
-static std::optional<TypeId> findTypeElementAt(AstTypePack* astTypePack, TypePackId tp, Position position)
-{
-    LUAU_ASSERT(FFlag::LuauStoreReturnTypesAsPackOnAst);
-    if (const auto typePack = astTypePack->as<AstTypePackExplicit>())
-    {
-        return findTypeElementAt(typePack->typeList, tp, position);
-    }
-    else if (const auto variadic = astTypePack->as<AstTypePackVariadic>())
-    {
-        if (variadic->location.containsClosed(position))
-        {
-            auto [_, tail] = flatten(tp);
-
-            if (tail)
-            {
-                if (const VariadicTypePack* vtp = get<VariadicTypePack>(follow(*tail)))
-                    return findTypeElementAt(variadic->variadicType, vtp->ty, position);
-            }
-        }
-    }
-
-    return {};
-}
-
 static std::optional<TypeId> findTypeElementAt(AstType* astType, TypeId ty, Position position)
 {
     ty = follow(ty);
@@ -743,17 +720,9 @@ static std::optional<TypeId> findTypeElementAt(AstType* astType, TypeId ty, Posi
         if (auto element = findTypeElementAt(type->argTypes, ftv->argTypes, position))
             return element;
 
-        if (FFlag::LuauStoreReturnTypesAsPackOnAst)
-        {
         if (auto element = findTypeElementAt(type->returnTypes, ftv->retTypes, position))
             return element;
     }
-        else
-        {
-            if (auto element = findTypeElementAt(type->returnTypes_DEPRECATED, ftv->retTypes, position))
-                return element;
-        }
-    }
 
     // It's possible to walk through other types like intrsection and unions if we find value in doing that
     return {};
@@ -761,7 +730,7 @@ static std::optional<TypeId> findTypeElementAt(AstType* astType, TypeId ty, Posi
 
 std::optional<TypeId> getLocalTypeInScopeAt(const Module& module, const ScopePtr& scopeAtPosition, Position position, AstLocal* local)
 {
-    if (ScopePtr scope = scopeAtPosition)
+    if (ScopePtr scope = FFlag::LuauAutocompleteRefactorsForIncrementalAutocomplete ? scopeAtPosition : findScopeAtPosition(module, position))
     {
         for (const auto& [name, binding] : scope->bindings)
         {
@@ -903,7 +872,7 @@ AutocompleteEntryMap autocompleteTypeNames(
 {
     AutocompleteEntryMap result;
 
-    ScopePtr startScope = scopeAtPosition;
+    ScopePtr startScope = FFlag::LuauAutocompleteRefactorsForIncrementalAutocomplete ? scopeAtPosition : findScopeAtPosition(module, position);
 
     for (ScopePtr scope = startScope; scope; scope = scope->parent)
     {
@@ -1082,16 +1051,12 @@ AutocompleteEntryMap autocompleteTypeNames(
             }
         }
 
-        if (FFlag::LuauStoreReturnTypesAsPackOnAst)
-        {
         if (!node->returnAnnotation)
             return result;
 
-            if (const auto typePack = node->returnAnnotation->as<AstTypePackExplicit>())
+        for (size_t i = 0; i < node->returnAnnotation->types.size; i++)
         {
-                for (size_t i = 0; i < typePack->typeList.types.size; i++)
+            AstType* ret = node->returnAnnotation->types.data[i];
-                {
-                    AstType* ret = typePack->typeList.types.data[i];
 
             if (ret->location.containsClosed(position))
             {
@@ -1106,7 +1071,7 @@ AutocompleteEntryMap autocompleteTypeNames(
             }
         }
 
-                if (AstTypePack* retTp = typePack->typeList.tailType)
+        if (AstTypePack* retTp = node->returnAnnotation->tailType)
         {
             if (auto variadic = retTp->as<AstTypePackVariadic>())
             {
@@ -1121,56 +1086,6 @@ AutocompleteEntryMap autocompleteTypeNames(
             }
         }
     }
-            else if (auto variadic = node->returnAnnotation->as<AstTypePackVariadic>())
-            {
-                if (variadic->location.containsClosed(position))
-                {
-                    if (const FunctionType* ftv = tryGetExpectedFunctionType(module, node))
-                    {
-                        if (auto ty = tryGetTypePackTypeAt(ftv->retTypes, ~0u))
-                            tryAddTypeCorrectSuggestion(result, startScope, topType, *ty, position);
-                    }
-                }
-            }
-        }
-        else
-        {
-            if (!node->returnAnnotation_DEPRECATED)
-                return result;
-
-            for (size_t i = 0; i < node->returnAnnotation_DEPRECATED->types.size; i++)
-            {
-                AstType* ret = node->returnAnnotation_DEPRECATED->types.data[i];
-
-                if (ret->location.containsClosed(position))
-                {
-                    if (const FunctionType* ftv = tryGetExpectedFunctionType(module, node))
-                    {
-                        if (auto ty = tryGetTypePackTypeAt(ftv->retTypes, i))
-                            tryAddTypeCorrectSuggestion(result, startScope, topType, *ty, position);
-                    }
-
-                    // TODO: with additional type information, we could suggest inferred return type here
-                    break;
-                }
-            }
-
-            if (AstTypePack* retTp = node->returnAnnotation_DEPRECATED->tailType)
-            {
-                if (auto variadic = retTp->as<AstTypePackVariadic>())
-                {
-                    if (variadic->location.containsClosed(position))
-                    {
-                        if (const FunctionType* ftv = tryGetExpectedFunctionType(module, node))
-                        {
-                            if (auto ty = tryGetTypePackTypeAt(ftv->retTypes, ~0u))
-                                tryAddTypeCorrectSuggestion(result, startScope, topType, *ty, position);
-                        }
-                    }
-                }
-            }
-        }
-    }
 
     return result;
 }
@@ -1290,7 +1205,7 @@ static AutocompleteEntryMap autocompleteStatement(
 )
 {
     // This is inefficient. :(
-    ScopePtr scope = scopeAtPosition;
+    ScopePtr scope = FFlag::LuauAutocompleteRefactorsForIncrementalAutocomplete ? scopeAtPosition : findScopeAtPosition(module, position);
 
     AutocompleteEntryMap result;
 
@@ -1468,7 +1383,7 @@ static AutocompleteContext autocompleteExpression(
     else
     {
         // This is inefficient. :(
-        ScopePtr scope = scopeAtPosition;
+        ScopePtr scope = FFlag::LuauAutocompleteRefactorsForIncrementalAutocomplete ? scopeAtPosition : findScopeAtPosition(module, position);
 
         while (scope)
         {
@@ -1537,7 +1452,7 @@ static AutocompleteResult autocompleteExpression(
     return {result, ancestry, context};
 }
 
-static std::optional<const ExternType*> getMethodContainingExternType(const ModulePtr& module, AstExpr* funcExpr)
+static std::optional<const ClassType*> getMethodContainingClass(const ModulePtr& module, AstExpr* funcExpr)
 {
     AstExpr* parentExpr = nullptr;
     if (auto indexName = funcExpr->as<AstExprIndexName>())
@@ -1561,14 +1476,14 @@ static std::optional<const ExternType*> getMethodContainingExternType(const Modu
 
     Luau::TypeId parentType = Luau::follow(*parentIt);
 
-    if (auto parentExternType = Luau::get<ExternType>(parentType))
+    if (auto parentClass = Luau::get<ClassType>(parentType))
     {
-        return parentExternType;
+        return parentClass;
     }
 
     if (auto parentUnion = Luau::get<UnionType>(parentType))
     {
-        return returnFirstNonnullOptionOfType<ExternType>(parentUnion);
+        return returnFirstNonnullOptionOfType<ClassType>(parentUnion);
     }
 
     return std::nullopt;
@@ -1626,7 +1541,10 @@ static std::optional<AutocompleteEntryMap> convertRequireSuggestionsToAutocomple
     {
         AutocompleteEntry entry = {AutocompleteEntryKind::RequirePath};
         entry.insertText = std::move(suggestion.fullPath);
+        if (FFlag::LuauExposeRequireByStringAutocomplete)
+        {
             entry.tags = std::move(suggestion.tags);
+        }
         result[std::move(suggestion.label)] = std::move(entry);
     }
     return result;
@@ -1687,7 +1605,7 @@ static std::optional<AutocompleteEntryMap> autocompleteStringParams(
             {
                 return convertRequireSuggestionsToAutocompleteEntryMap(fileResolver->getRequireSuggestions(module->name, candidateString));
             }
-            if (std::optional<AutocompleteEntryMap> ret = callback(tag, getMethodContainingExternType(module, candidate->func), candidateString))
+            if (std::optional<AutocompleteEntryMap> ret = callback(tag, getMethodContainingClass(module, candidate->func), candidateString))
             {
                 return ret;
             }
@@ -1705,8 +1623,6 @@ static std::optional<AutocompleteEntryMap> autocompleteStringParams(
     {
         for (TypeId part : intersect->parts)
         {
-            if (FFlag::LuauAutocompleteMissingFollows)
-                part = follow(part);
             if (auto candidateFunctionType = Luau::get<FunctionType>(part))
             {
                 if (std::optional<AutocompleteEntryMap> ret = performCallback(candidateFunctionType))
@@ -1855,7 +1771,7 @@ static std::optional<AutocompleteEntry> makeAnonymousAutofilled(
     if (!type)
         return std::nullopt;
 
-    const ScopePtr scope = scopeAtPosition;
+    const ScopePtr scope = FFlag::LuauAutocompleteRefactorsForIncrementalAutocomplete ? scopeAtPosition : findScopeAtPosition(*module, position);
     if (!scope)
         return std::nullopt;
 

Analysis/src/BuiltinDefinitions.cpp

@@ -3,23 +3,22 @@
 
 #include "Luau/Ast.h"
 #include "Luau/Clone.h"
-#include "Luau/Common.h"
-#include "Luau/ConstraintGenerator.h"
-#include "Luau/ConstraintSolver.h"
 #include "Luau/DenseHash.h"
 #include "Luau/Error.h"
 #include "Luau/Frontend.h"
-#include "Luau/InferPolarity.h"
-#include "Luau/NotNull.h"
-#include "Luau/Subtyping.h"
 #include "Luau/Symbol.h"
+#include "Luau/Common.h"
 #include "Luau/ToString.h"
-#include "Luau/Type.h"
+#include "Luau/ConstraintSolver.h"
+#include "Luau/ConstraintGenerator.h"
+#include "Luau/NotNull.h"
+#include "Luau/TypeInfer.h"
 #include "Luau/TypeChecker2.h"
 #include "Luau/TypeFunction.h"
-#include "Luau/TypeInfer.h"
 #include "Luau/TypePack.h"
+#include "Luau/Type.h"
 #include "Luau/TypeUtils.h"
+#include "Luau/Subtyping.h"
 
 #include <algorithm>
 
@@ -30,11 +29,11 @@
  */
 
 LUAU_FASTFLAG(LuauSolverV2)
-LUAU_FASTFLAG(LuauNonReentrantGeneralization2)
+LUAU_FASTFLAGVARIABLE(LuauStringFormatErrorSuppression)
 LUAU_FASTFLAGVARIABLE(LuauTableCloneClonesType3)
+LUAU_FASTFLAG(LuauTrackInteriorFreeTypesOnScope)
+LUAU_FASTFLAGVARIABLE(LuauFollowTableFreeze)
 LUAU_FASTFLAGVARIABLE(LuauUserTypeFunTypecheck)
-LUAU_FASTFLAGVARIABLE(LuauMagicFreezeCheckBlocked)
-LUAU_FASTFLAGVARIABLE(LuauFormatUseLastPosition)
 
 namespace Luau
 {
@@ -248,7 +247,6 @@ void addGlobalBinding(GlobalTypes& globals, const ScopePtr& scope, const std::st
 
 void addGlobalBinding(GlobalTypes& globals, const ScopePtr& scope, const std::string& name, Binding binding)
 {
-    inferGenericPolarities(NotNull{&globals.globalTypes}, NotNull{scope.get()}, binding.typeId);
     scope->bindings[globals.globalNames.names->getOrAdd(name.c_str())] = binding;
 }
 
@@ -313,9 +311,6 @@ void registerBuiltinGlobals(Frontend& frontend, GlobalTypes& globals, bool typeC
 
     TypeArena& arena = globals.globalTypes;
     NotNull<BuiltinTypes> builtinTypes = globals.builtinTypes;
-    Scope* globalScope = nullptr; // NotNull<Scope> when removing FFlag::LuauNonReentrantGeneralization2
-    if (FFlag::LuauNonReentrantGeneralization2)
-        globalScope = globals.globalScope.get();
 
     if (FFlag::LuauSolverV2)
         builtinTypeFunctions().addToScope(NotNull{&arena}, NotNull{globals.globalScope.get()});
@@ -325,8 +320,8 @@ void registerBuiltinGlobals(Frontend& frontend, GlobalTypes& globals, bool typeC
     );
     LUAU_ASSERT(loadResult.success);
 
-    TypeId genericK = arena.addType(GenericType{globalScope, "K"});
+    TypeId genericK = arena.addType(GenericType{"K"});
-    TypeId genericV = arena.addType(GenericType{globalScope, "V"});
+    TypeId genericV = arena.addType(GenericType{"V"});
     TypeId mapOfKtoV = arena.addType(TableType{{}, TableIndexer(genericK, genericV), globals.globalScope->level, TableState::Generic});
 
     std::optional<TypeId> stringMetatableTy = getMetatable(builtinTypes->stringType, builtinTypes);
@@ -343,7 +338,7 @@ void registerBuiltinGlobals(Frontend& frontend, GlobalTypes& globals, bool typeC
     if (auto it = globals.globalScope->exportedTypeBindings.find("vector"); it != globals.globalScope->exportedTypeBindings.end())
     {
         TypeId vectorTy = it->second.type;
-        ExternType* vectorCls = getMutable<ExternType>(vectorTy);
+        ClassType* vectorCls = getMutable<ClassType>(vectorTy);
 
         vectorCls->metatable = arena.addType(TableType{{}, std::nullopt, TypeLevel{}, TableState::Sealed});
         TableType* metatableTy = Luau::getMutable<TableType>(vectorCls->metatable);
@@ -374,7 +369,7 @@ void registerBuiltinGlobals(Frontend& frontend, GlobalTypes& globals, bool typeC
     // pairs<K, V>(t: Table<K, V>) -> ((Table<K, V>, K?) -> (K, V), Table<K, V>, nil)
     addGlobalBinding(globals, "pairs", arena.addType(FunctionType{{genericK, genericV}, {}, pairsArgsTypePack, pairsReturnTypePack}), "@luau");
 
-    TypeId genericMT = arena.addType(GenericType{globalScope, "MT"});
+    TypeId genericMT = arena.addType(GenericType{"MT"});
 
     TableType tab{TableState::Generic, globals.globalScope->level};
     TypeId tabTy = arena.addType(tab);
@@ -386,7 +381,7 @@ void registerBuiltinGlobals(Frontend& frontend, GlobalTypes& globals, bool typeC
 
     if (FFlag::LuauSolverV2)
     {
-        TypeId genericT = arena.addType(GenericType{globalScope, "T"});
+        TypeId genericT = arena.addType(GenericType{"T"});
         TypeId tMetaMT = arena.addType(MetatableType{genericT, genericMT});
 
         // clang-format off
@@ -443,7 +438,7 @@ void registerBuiltinGlobals(Frontend& frontend, GlobalTypes& globals, bool typeC
     if (FFlag::LuauSolverV2)
     {
         // declare function assert<T>(value: T, errorMessage: string?): intersect<T, ~(false?)>
-        TypeId genericT = arena.addType(GenericType{globalScope, "T"});
+        TypeId genericT = arena.addType(GenericType{"T"});
         TypeId refinedTy = arena.addType(TypeFunctionInstanceType{
             NotNull{&builtinTypeFunctions().intersectFunc}, {genericT, arena.addType(NegationType{builtinTypes->falsyType})}, {}
         });
@@ -466,16 +461,12 @@ void registerBuiltinGlobals(Frontend& frontend, GlobalTypes& globals, bool typeC
             // the top table type.  We do the best we can by modelling these
             // functions using unconstrained generics.  It's not quite right,
             // but it'll be ok for now.
-            TypeId genericTy = arena.addType(GenericType{globalScope, "T"});
+            TypeId genericTy = arena.addType(GenericType{"T"});
             TypePackId thePack = arena.addTypePack({genericTy});
             TypeId idTyWithMagic = arena.addType(FunctionType{{genericTy}, {}, thePack, thePack});
             ttv->props["freeze"] = makeProperty(idTyWithMagic, "@luau/global/table.freeze");
-            if (globalScope)
-                inferGenericPolarities(NotNull{&globals.globalTypes}, NotNull{globalScope}, idTyWithMagic);
 
             TypeId idTy = arena.addType(FunctionType{{genericTy}, {}, thePack, thePack});
-            if (globalScope)
-                inferGenericPolarities(NotNull{&globals.globalTypes}, NotNull{globalScope}, idTy);
             ttv->props["clone"] = makeProperty(idTy, "@luau/global/table.clone");
         }
         else
@@ -704,14 +695,6 @@ bool MagicFormat::typeCheck(const MagicFunctionTypeCheckContext& context)
         return true;
     }
 
-    // CLI-150726: The block below effectively constructs a type pack and then type checks it by going parameter-by-parameter.
-    // This does _not_ handle cases like:
-    //
-    //  local foo : () -> (...string) = (nil :: any)
-    //  print(string.format("%s %d %s", foo()))
-    //
-    // ... which should be disallowed.
-
     std::vector<TypeId> expected = parseFormatString(context.builtinTypes, fmt->value.data, fmt->value.size);
     const auto& [params, tail] = flatten(context.arguments);
 
@@ -723,13 +706,13 @@ bool MagicFormat::typeCheck(const MagicFunctionTypeCheckContext& context)
     {
         TypeId actualTy = params[i + paramOffset];
         TypeId expectedTy = expected[i];
-        Location location = FFlag::LuauFormatUseLastPosition
+        Location location = context.callSite->args.data[i + (calledWithSelf ? 0 : paramOffset)]->location;
-            ? context.callSite->args.data[std::min(context.callSite->args.size - 1, i + (calledWithSelf ? 0 : paramOffset))]->location
-            : context.callSite->args.data[i + (calledWithSelf ? 0 : paramOffset)]->location;
         // use subtyping instead here
         SubtypingResult result = context.typechecker->subtyping->isSubtype(actualTy, expectedTy, context.checkScope);
 
         if (!result.isSubtype)
+        {
+            if (FFlag::LuauStringFormatErrorSuppression)
             {
                 switch (shouldSuppressErrors(NotNull{&context.typechecker->normalizer}, actualTy))
                 {
@@ -744,6 +727,12 @@ bool MagicFormat::typeCheck(const MagicFunctionTypeCheckContext& context)
                         context.typechecker->reportError(TypeMismatch{expectedTy, actualTy, reasonings.toString()}, location);
                 }
             }
+            else
+            {
+                Reasonings reasonings = context.typechecker->explainReasonings(actualTy, expectedTy, location, result);
+                context.typechecker->reportError(TypeMismatch{expectedTy, actualTy, reasonings.toString()}, location);
+            }
+        }
     }
 
     return true;
@@ -1538,6 +1527,7 @@ bool MagicClone::infer(const MagicFunctionCallContext& context)
         tableType->scope = context.constraint->scope.get();
     }
 
+    if (FFlag::LuauTrackInteriorFreeTypesOnScope)
         trackInteriorFreeType(context.constraint->scope.get(), resultType);
 
     TypePackId clonedTypePack = arena->addTypePack({resultType});
@@ -1549,6 +1539,7 @@ bool MagicClone::infer(const MagicFunctionCallContext& context)
 static std::optional<TypeId> freezeTable(TypeId inputType, const MagicFunctionCallContext& context)
 {
     TypeArena* arena = context.solver->arena;
+    if (FFlag::LuauFollowTableFreeze)
         inputType = follow(inputType);
     if (auto mt = get<MetatableType>(inputType))
     {
@@ -1616,17 +1607,6 @@ bool MagicFreeze::infer(const MagicFunctionCallContext& context)
     std::optional<DefId> resultDef = dfg->getDefOptional(targetExpr);
     std::optional<TypeId> resultTy = resultDef ? scope->lookup(*resultDef) : std::nullopt;
 
-    if (FFlag::LuauMagicFreezeCheckBlocked)
-    {
-        if (resultTy && !get<BlockedType>(resultTy))
-        {
-            // If there's an existing result type but it's _not_ blocked, then
-            // we aren't type stating this builtin and should fall back to
-            // regular inference.
-            return false;
-        }
-    }
-
     std::optional<TypeId> frozenType = freezeTable(inputType, context);
 
     if (!frozenType)

Analysis/src/Clone.cpp

@@ -179,6 +179,8 @@ public:
             generic->scope = nullptr;
         else if (auto free = getMutable<FreeType>(target))
             free->scope = nullptr;
+        else if (auto fn = getMutable<FunctionType>(target))
+            fn->scope = nullptr;
         else if (auto table = getMutable<TableType>(target))
             table->scope = nullptr;
 
@@ -355,7 +357,7 @@ private:
         t->metatable = shallowClone(t->metatable);
     }
 
-    void cloneChildren(ExternType* t)
+    void cloneChildren(ClassType* t)
     {
         for (auto& [_, p] : t->props)
             p = shallowClone(p);
@@ -519,6 +521,11 @@ public:
             if (FFlag::LuauClonedTableAndFunctionTypesMustHaveScopes)
                 tt->scope = replacementForNullScope;
         }
+        else if (auto fn = getMutable<FunctionType>(target))
+        {
+            if (FFlag::LuauClonedTableAndFunctionTypesMustHaveScopes)
+                fn->scope = replacementForNullScope;
+        }
 
         (*types)[ty] = target;
         queue.emplace_back(target);

Analysis/src/Constraint.cpp

@@ -20,7 +20,7 @@ struct ReferenceCountInitializer : TypeOnceVisitor
 
     DenseHashSet<TypeId>* result;
 
-    explicit ReferenceCountInitializer(DenseHashSet<TypeId>* result)
+    ReferenceCountInitializer(DenseHashSet<TypeId>* result)
         : result(result)
     {
     }
@@ -43,15 +43,24 @@ struct ReferenceCountInitializer : TypeOnceVisitor
         return false;
     }
 
-    bool visit(TypeId ty, const ExternType&) override
+    bool visit(TypeId ty, const ClassType&) override
     {
-        // ExternTypes never contain free types.
+        // ClassTypes never contain free types.
         return false;
     }
 
     bool visit(TypeId, const TypeFunctionInstanceType&) override
     {
-        return FFlag::DebugLuauGreedyGeneralization;
+        // We do not consider reference counted types that are inside a type
+        // function to be part of the reachable reference counted types.
+        // Otherwise, code can be constructed in just the right way such
+        // that two type functions both claim to mutate a free type, which
+        // prevents either type function from trying to generalize it, so
+        // we potentially get stuck.
+        //
+        // The default behavior here is `true` for "visit the child types"
+        // of this type, hence:
+        return false;
     }
 };
 
@@ -121,10 +130,8 @@ DenseHashSet<TypeId> Constraint::getMaybeMutatedFreeTypes() const
     }
     else if (auto hic = get<HasIndexerConstraint>(*this))
     {
-        if (FFlag::DebugLuauGreedyGeneralization)
-            rci.traverse(hic->subjectType);
         rci.traverse(hic->resultType);
-        // `HasIndexerConstraint` should not mutate `indexType`.
+        // `HasIndexerConstraint` should not mutate `subjectType` or `indexType`.
     }
     else if (auto apc = get<AssignPropConstraint>(*this))
     {
@@ -143,10 +150,6 @@ DenseHashSet<TypeId> Constraint::getMaybeMutatedFreeTypes() const
             rci.traverse(ty);
         // `UnpackConstraint` should not mutate `sourcePack`.
     }
-    else if (auto rpc = get<ReduceConstraint>(*this); FFlag::DebugLuauGreedyGeneralization && rpc)
-    {
-        rci.traverse(rpc->ty);
-    }
     else if (auto rpc = get<ReducePackConstraint>(*this))
     {
         rci.traverse(rpc->tp);

Analysis/src/DataFlowGraph.cpp

@@ -13,25 +13,32 @@
 
 LUAU_FASTFLAG(DebugLuauFreezeArena)
 LUAU_FASTFLAG(LuauSolverV2)
-LUAU_FASTFLAGVARIABLE(LuauPreprocessTypestatedArgument)
+
-LUAU_FASTFLAGVARIABLE(LuauDfgScopeStackTrueReset)
-LUAU_FASTFLAGVARIABLE(LuauDfgScopeStackNotNull)
-LUAU_FASTFLAG(LuauStoreReturnTypesAsPackOnAst)
-LUAU_FASTFLAGVARIABLE(LuauDoNotAddUpvalueTypesToLocalType)
-LUAU_FASTFLAGVARIABLE(LuauDfgIfBlocksShouldRespectControlFlow)
 namespace Luau
 {
 
 bool doesCallError(const AstExprCall* call); // TypeInfer.cpp
 
+struct ReferencedDefFinder : public AstVisitor
+{
+    bool visit(AstExprLocal* local) override
+    {
+        referencedLocalDefs.push_back(local->local);
+        return true;
+    }
+    // ast defs is just a mapping from expr -> def in general
+    // will get built up by the dfg builder
+
+    // localDefs, we need to copy over
+    std::vector<AstLocal*> referencedLocalDefs;
+};
+
 struct PushScope
 {
     ScopeStack& stack;
-    size_t previousSize;
 
     PushScope(ScopeStack& stack, DfgScope* scope)
         : stack(stack)
-        , previousSize(stack.size())
     {
         // `scope` should never be `nullptr` here.
         LUAU_ASSERT(scope);
@@ -40,19 +47,8 @@ struct PushScope
 
     ~PushScope()
     {
-        if (FFlag::LuauDfgScopeStackTrueReset)
-        {
-            // If somehow this stack has _shrunk_ to be smaller than we expect,
-            // something very strange has happened.
-            LUAU_ASSERT(stack.size() > previousSize);
-            while (stack.size() > previousSize)
         stack.pop_back();
     }
-        else
-        {
-            stack.pop_back();
-        }
-    }
 };
 
 const RefinementKey* RefinementKeyArena::leaf(DefId def)
@@ -86,6 +82,12 @@ std::optional<DefId> DataFlowGraph::getDefOptional(const AstExpr* expr) const
     return NotNull{*def};
 }
 
+std::optional<DefId> DataFlowGraph::getRValueDefForCompoundAssign(const AstExpr* expr) const
+{
+    auto def = compoundAssignDefs.find(expr);
+    return def ? std::optional<DefId>(*def) : std::nullopt;
+}
+
 DefId DataFlowGraph::getDef(const AstLocal* local) const
 {
     auto def = localDefs.find(local);
@@ -199,15 +201,7 @@ DataFlowGraph DataFlowGraphBuilder::build(
 
     DataFlowGraphBuilder builder(defArena, keyArena);
     builder.handle = handle;
-
+    DfgScope* moduleScope = builder.makeChildScope();
-    DfgScope* moduleScope;
-    // We're not explicitly calling makeChildScope here because that function relies on currentScope
-    // which guarantees that the scope being returned is NotNull
-    // This means that while the scope stack is empty, we'll have to manually initialize the global scope
-    if (FFlag::LuauDfgScopeStackNotNull)
-        moduleScope = builder.scopes.emplace_back(new DfgScope{nullptr, DfgScope::ScopeType::Linear}).get();
-    else
-        moduleScope = builder.makeChildScope();
     PushScope ps{builder.scopeStack, moduleScope};
     builder.visitBlockWithoutChildScope(block);
     builder.resolveCaptures();
@@ -239,13 +233,7 @@ void DataFlowGraphBuilder::resolveCaptures()
     }
 }
 
-NotNull<DfgScope> DataFlowGraphBuilder::currentScope()
+DfgScope* DataFlowGraphBuilder::currentScope()
-{
-    LUAU_ASSERT(!scopeStack.empty());
-    return NotNull{scopeStack.back()};
-}
-
-DfgScope* DataFlowGraphBuilder::currentScope_DEPRECATED()
 {
     if (scopeStack.empty())
         return nullptr; // nullptr is the root DFG scope.
@@ -254,10 +242,7 @@ DfgScope* DataFlowGraphBuilder::currentScope_DEPRECATED()
 
 DfgScope* DataFlowGraphBuilder::makeChildScope(DfgScope::ScopeType scopeType)
 {
-    if (FFlag::LuauDfgScopeStackNotNull)
     return scopes.emplace_back(new DfgScope{currentScope(), scopeType}).get();
-    else
-        return scopes.emplace_back(new DfgScope{currentScope_DEPRECATED(), scopeType}).get();
 }
 
 void DataFlowGraphBuilder::join(DfgScope* p, DfgScope* a, DfgScope* b)
@@ -332,9 +317,9 @@ void DataFlowGraphBuilder::joinProps(DfgScope* result, const DfgScope& a, const
     }
 }
 
-DefId DataFlowGraphBuilder::lookup(Symbol symbol, Location location)
+DefId DataFlowGraphBuilder::lookup(Symbol symbol)
 {
-    DfgScope* scope = FFlag::LuauDfgScopeStackNotNull ? currentScope() : currentScope_DEPRECATED();
+    DfgScope* scope = currentScope();
 
     // true if any of the considered scopes are a loop.
     bool outsideLoopScope = false;
@@ -359,15 +344,15 @@ DefId DataFlowGraphBuilder::lookup(Symbol symbol, Location location)
         }
     }
 
-    DefId result = defArena->freshCell(symbol, location);
+    DefId result = defArena->freshCell();
     scope->bindings[symbol] = result;
     captures[symbol].allVersions.push_back(result);
     return result;
 }
 
-DefId DataFlowGraphBuilder::lookup(DefId def, const std::string& key, Location location)
+DefId DataFlowGraphBuilder::lookup(DefId def, const std::string& key)
 {
-    DfgScope* scope = FFlag::LuauDfgScopeStackNotNull ? currentScope() : currentScope_DEPRECATED();
+    DfgScope* scope = currentScope();
     for (DfgScope* current = scope; current; current = current->parent)
     {
         if (auto props = current->props.find(def))
@@ -377,7 +362,7 @@ DefId DataFlowGraphBuilder::lookup(DefId def, const std::string& key, Location l
         }
         else if (auto phi = get<Phi>(def); phi && phi->operands.empty()) // Unresolved phi nodes
         {
-            DefId result = defArena->freshCell(def->name, location);
+            DefId result = defArena->freshCell();
             scope->props[def][key] = result;
             return result;
         }
@@ -387,7 +372,7 @@ DefId DataFlowGraphBuilder::lookup(DefId def, const std::string& key, Location l
     {
         std::vector<DefId> defs;
         for (DefId operand : phi->operands)
-            defs.push_back(lookup(operand, key, location));
+            defs.push_back(lookup(operand, key));
 
         DefId result = defArena->phi(defs);
         scope->props[def][key] = result;
@@ -395,7 +380,7 @@ DefId DataFlowGraphBuilder::lookup(DefId def, const std::string& key, Location l
     }
     else if (get<Cell>(def))
     {
-        DefId result = defArena->freshCell(def->name, location);
+        DefId result = defArena->freshCell();
         scope->props[def][key] = result;
         return result;
     }
@@ -413,10 +398,7 @@ ControlFlow DataFlowGraphBuilder::visit(AstStatBlock* b)
         cf = visitBlockWithoutChildScope(b);
     }
 
-    if (FFlag::LuauDfgScopeStackNotNull)
     currentScope()->inherit(child);
-    else
-        currentScope_DEPRECATED()->inherit(child);
     return cf;
 }
 
@@ -473,7 +455,7 @@ ControlFlow DataFlowGraphBuilder::visit(AstStat* s)
         return visit(d);
     else if (auto d = s->as<AstStatDeclareFunction>())
         return visit(d);
-    else if (auto d = s->as<AstStatDeclareExternType>())
+    else if (auto d = s->as<AstStatDeclareClass>())
         return visit(d);
     else if (auto error = s->as<AstStatError>())
         return visit(error);
@@ -501,27 +483,13 @@ ControlFlow DataFlowGraphBuilder::visit(AstStatIf* i)
         elsecf = visit(i->elsebody);
     }
 
-    DfgScope* scope = FFlag::LuauDfgScopeStackNotNull ? currentScope() : currentScope_DEPRECATED();
+    DfgScope* scope = currentScope();
-    if (FFlag::LuauDfgIfBlocksShouldRespectControlFlow)
-    {
-        // If the control flow from the `if` or `else` block is non-linear,
-        // then we should assume that the _other_ branch is the one taken.
-        if (thencf != ControlFlow::None && elsecf == ControlFlow::None)
-            scope->inherit(elseScope);
-        else if (thencf == ControlFlow::None && elsecf != ControlFlow::None)
-            scope->inherit(thenScope);
-        else if ((thencf | elsecf) == ControlFlow::None)
-            join(scope, thenScope, elseScope);
-    }
-    else
-    {
     if (thencf != ControlFlow::None && elsecf == ControlFlow::None)
         join(scope, scope, elseScope);
     else if (thencf == ControlFlow::None && elsecf != ControlFlow::None)
         join(scope, thenScope, scope);
     else if ((thencf | elsecf) == ControlFlow::None)
         join(scope, thenScope, elseScope);
-    }
 
     if (thencf == elsecf)
         return thencf;
@@ -542,10 +510,7 @@ ControlFlow DataFlowGraphBuilder::visit(AstStatWhile* w)
         visit(w->body);
     }
 
-    if (FFlag::LuauDfgScopeStackNotNull)
     currentScope()->inherit(whileScope);
-    else
-        currentScope_DEPRECATED()->inherit(whileScope);
 
     return ControlFlow::None;
 }
@@ -561,10 +526,7 @@ ControlFlow DataFlowGraphBuilder::visit(AstStatRepeat* r)
         visitExpr(r->condition);
     }
 
-    if (FFlag::LuauDfgScopeStackNotNull)
     currentScope()->inherit(repeatScope);
-    else
-        currentScope_DEPRECATED()->inherit(repeatScope);
 
     return ControlFlow::None;
 }
@@ -613,7 +575,7 @@ ControlFlow DataFlowGraphBuilder::visit(AstStatLocal* l)
         // We need to create a new def to intentionally avoid alias tracking, but we'd like to
         // make sure that the non-aliased defs are also marked as a subscript for refinements.
         bool subscripted = i < defs.size() && containsSubscriptedDefinition(defs[i]);
-        DefId def = defArena->freshCell(local, local->location, subscripted);
+        DefId def = defArena->freshCell(subscripted);
         if (i < l->values.size)
         {
             AstExpr* e = l->values.data[i];
@@ -623,10 +585,7 @@ ControlFlow DataFlowGraphBuilder::visit(AstStatLocal* l)
             }
         }
         graph.localDefs[local] = def;
-        if (FFlag::LuauDfgScopeStackNotNull)
         currentScope()->bindings[local] = def;
-        else
-            currentScope_DEPRECATED()->bindings[local] = def;
         captures[local].allVersions.push_back(def);
     }
 
@@ -648,22 +607,16 @@ ControlFlow DataFlowGraphBuilder::visit(AstStatFor* f)
         if (f->var->annotation)
             visitType(f->var->annotation);
 
-        DefId def = defArena->freshCell(f->var, f->var->location);
+        DefId def = defArena->freshCell();
         graph.localDefs[f->var] = def;
-        if (FFlag::LuauDfgScopeStackNotNull)
         currentScope()->bindings[f->var] = def;
-        else
-            currentScope_DEPRECATED()->bindings[f->var] = def;
         captures[f->var].allVersions.push_back(def);
 
         // TODO(controlflow): entry point has a back edge from exit point
         visit(f->body);
     }
 
-    if (FFlag::LuauDfgScopeStackNotNull)
     currentScope()->inherit(forScope);
-    else
-        currentScope_DEPRECATED()->inherit(forScope);
 
     return ControlFlow::None;
 }
@@ -680,12 +633,9 @@ ControlFlow DataFlowGraphBuilder::visit(AstStatForIn* f)
             if (local->annotation)
                 visitType(local->annotation);
 
-            DefId def = defArena->freshCell(local, local->location);
+            DefId def = defArena->freshCell();
             graph.localDefs[local] = def;
-            if (FFlag::LuauDfgScopeStackNotNull)
             currentScope()->bindings[local] = def;
-            else
-                currentScope_DEPRECATED()->bindings[local] = def;
             captures[local].allVersions.push_back(def);
         }
 
@@ -696,10 +646,8 @@ ControlFlow DataFlowGraphBuilder::visit(AstStatForIn* f)
 
         visit(f->body);
     }
-    if (FFlag::LuauDfgScopeStackNotNull)
+
     currentScope()->inherit(forScope);
-    else
-        currentScope_DEPRECATED()->inherit(forScope);
 
     return ControlFlow::None;
 }
@@ -714,7 +662,7 @@ ControlFlow DataFlowGraphBuilder::visit(AstStatAssign* a)
     for (size_t i = 0; i < a->vars.size; ++i)
     {
         AstExpr* v = a->vars.data[i];
-        visitLValue(v, i < defs.size() ? defs[i] : defArena->freshCell(Symbol{}, v->location));
+        visitLValue(v, i < defs.size() ? defs[i] : defArena->freshCell());
     }
 
     return ControlFlow::None;
@@ -740,7 +688,7 @@ ControlFlow DataFlowGraphBuilder::visit(AstStatFunction* f)
     //
     // which is evidence that references to variables must be a phi node of all possible definitions,
     // but for bug compatibility, we'll assume the same thing here.
-    visitLValue(f->name, defArena->freshCell(Symbol{}, f->name->location));
+    visitLValue(f->name, defArena->freshCell());
     visitExpr(f->func);
 
     if (auto local = f->name->as<AstExprLocal>())
@@ -760,12 +708,9 @@ ControlFlow DataFlowGraphBuilder::visit(AstStatFunction* f)
 
 ControlFlow DataFlowGraphBuilder::visit(AstStatLocalFunction* l)
 {
-    DefId def = defArena->freshCell(l->name, l->location);
+    DefId def = defArena->freshCell();
     graph.localDefs[l->name] = def;
-    if (FFlag::LuauDfgScopeStackNotNull)
     currentScope()->bindings[l->name] = def;
-    else
-        currentScope_DEPRECATED()->bindings[l->name] = def;
     captures[l->name].allVersions.push_back(def);
     visitExpr(l->func);
 
@@ -796,12 +741,9 @@ ControlFlow DataFlowGraphBuilder::visit(AstStatTypeFunction* f)
 
 ControlFlow DataFlowGraphBuilder::visit(AstStatDeclareGlobal* d)
 {
-    DefId def = defArena->freshCell(d->name, d->nameLocation);
+    DefId def = defArena->freshCell();
     graph.declaredDefs[d] = def;
-    if (FFlag::LuauDfgScopeStackNotNull)
     currentScope()->bindings[d->name] = def;
-    else
-        currentScope_DEPRECATED()->bindings[d->name] = def;
     captures[d->name].allVersions.push_back(def);
 
     visitType(d->type);
@@ -811,12 +753,9 @@ ControlFlow DataFlowGraphBuilder::visit(AstStatDeclareGlobal* d)
 
 ControlFlow DataFlowGraphBuilder::visit(AstStatDeclareFunction* d)
 {
-    DefId def = defArena->freshCell(d->name, d->nameLocation);
+    DefId def = defArena->freshCell();
     graph.declaredDefs[d] = def;
-    if (FFlag::LuauDfgScopeStackNotNull)
     currentScope()->bindings[d->name] = def;
-    else
-        currentScope_DEPRECATED()->bindings[d->name] = def;
     captures[d->name].allVersions.push_back(def);
 
     DfgScope* unreachable = makeChildScope();
@@ -825,15 +764,12 @@ ControlFlow DataFlowGraphBuilder::visit(AstStatDeclareFunction* d)
     visitGenerics(d->generics);
     visitGenericPacks(d->genericPacks);
     visitTypeList(d->params);
-    if (FFlag::LuauStoreReturnTypesAsPackOnAst)
+    visitTypeList(d->retTypes);
-        visitTypePack(d->retTypes);
-    else
-        visitTypeList(d->retTypes_DEPRECATED);
 
     return ControlFlow::None;
 }
 
-ControlFlow DataFlowGraphBuilder::visit(AstStatDeclareExternType* d)
+ControlFlow DataFlowGraphBuilder::visit(AstStatDeclareClass* d)
 {
     // This declaration does not "introduce" any bindings in value namespace,
     // so there's no symbolic value to begin with. We'll traverse the properties
@@ -841,7 +777,7 @@ ControlFlow DataFlowGraphBuilder::visit(AstStatDeclareExternType* d)
     DfgScope* unreachable = makeChildScope();
     PushScope ps{scopeStack, unreachable};
 
-    for (AstDeclaredExternTypeProperty prop : d->props)
+    for (AstDeclaredClassProp prop : d->props)
         visitType(prop.ty);
 
     return ControlFlow::None;
@@ -874,19 +810,19 @@ DataFlowResult DataFlowGraphBuilder::visitExpr(AstExpr* e)
         if (auto g = e->as<AstExprGroup>())
             return visitExpr(g);
         else if (auto c = e->as<AstExprConstantNil>())
-            return {defArena->freshCell(Symbol{}, c->location), nullptr}; // ok
+            return {defArena->freshCell(), nullptr}; // ok
         else if (auto c = e->as<AstExprConstantBool>())
-            return {defArena->freshCell(Symbol{}, c->location), nullptr}; // ok
+            return {defArena->freshCell(), nullptr}; // ok
         else if (auto c = e->as<AstExprConstantNumber>())
-            return {defArena->freshCell(Symbol{}, c->location), nullptr}; // ok
+            return {defArena->freshCell(), nullptr}; // ok
         else if (auto c = e->as<AstExprConstantString>())
-            return {defArena->freshCell(Symbol{}, c->location), nullptr}; // ok
+            return {defArena->freshCell(), nullptr}; // ok
         else if (auto l = e->as<AstExprLocal>())
             return visitExpr(l);
         else if (auto g = e->as<AstExprGlobal>())
             return visitExpr(g);
         else if (auto v = e->as<AstExprVarargs>())
-            return {defArena->freshCell(Symbol{}, v->location), nullptr}; // ok
+            return {defArena->freshCell(), nullptr}; // ok
         else if (auto c = e->as<AstExprCall>())
             return visitExpr(c);
         else if (auto i = e->as<AstExprIndexName>())
@@ -927,14 +863,14 @@ DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprGroup* group)
 
 DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprLocal* l)
 {
-    DefId def = lookup(l->local, l->local->location);
+    DefId def = lookup(l->local);
     const RefinementKey* key = keyArena->leaf(def);
     return {def, key};
 }
 
 DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprGlobal* g)
 {
-    DefId def = lookup(g->name, g->location);
+    DefId def = lookup(g->name);
     return {def, keyArena->leaf(def)};
 }
 
@@ -942,12 +878,6 @@ DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprCall* c)
 {
     visitExpr(c->func);
 
-    if (FFlag::LuauPreprocessTypestatedArgument)
-    {
-        for (AstExpr* arg : c->args)
-            visitExpr(arg);
-    }
-
     if (shouldTypestateForFirstArgument(*c) && c->args.size > 1 && isLValue(*c->args.begin()))
     {
         AstExpr* firstArg = *c->args.begin();
@@ -978,11 +908,8 @@ DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprCall* c)
         visitLValue(firstArg, def);
     }
 
-    if (!FFlag::LuauPreprocessTypestatedArgument)
-    {
     for (AstExpr* arg : c->args)
         visitExpr(arg);
-    }
 
     // We treat function calls as "subscripted" as they could potentially
     // return a subscripted value, consider:
@@ -994,7 +921,7 @@ DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprCall* c)
     //  local v = foo({})
     //
     // We want to consider `v` to be subscripted here.
-    return {defArena->freshCell(Symbol{}, c->location, /*subscripted=*/true)};
+    return {defArena->freshCell(/*subscripted=*/true)};
 }
 
 DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprIndexName* i)
@@ -1002,7 +929,7 @@ DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprIndexName* i)
     auto [parentDef, parentKey] = visitExpr(i->expr);
     std::string index = i->index.value;
 
-    DefId def = lookup(parentDef, index, i->location);
+    DefId def = lookup(parentDef, index);
     return {def, keyArena->node(parentKey, def, index)};
 }
 
@@ -1015,11 +942,11 @@ DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprIndexExpr* i)
     {
         std::string index{string->value.data, string->value.size};
 
-        DefId def = lookup(parentDef, index, i->location);
+        DefId def = lookup(parentDef, index);
         return {def, keyArena->node(parentKey, def, index)};
     }
 
-    return {defArena->freshCell(Symbol{}, i->location, /* subscripted= */ true), nullptr};
+    return {defArena->freshCell(/* subscripted= */ true), nullptr};
 }
 
 DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprFunction* f)
@@ -1032,7 +959,7 @@ DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprFunction* f)
         // There's no syntax for `self` to have an annotation if using `function t:m()`
         LUAU_ASSERT(!self->annotation);
 
-        DefId def = defArena->freshCell(f->debugname, f->location);
+        DefId def = defArena->freshCell();
         graph.localDefs[self] = def;
         signatureScope->bindings[self] = def;
         captures[self].allVersions.push_back(def);
@@ -1043,7 +970,7 @@ DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprFunction* f)
         if (param->annotation)
             visitType(param->annotation);
 
-        DefId def = defArena->freshCell(param, param->location);
+        DefId def = defArena->freshCell();
         graph.localDefs[param] = def;
         signatureScope->bindings[param] = def;
         captures[param].allVersions.push_back(def);
@@ -1052,16 +979,8 @@ DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprFunction* f)
     if (f->varargAnnotation)
         visitTypePack(f->varargAnnotation);
 
-    if (FFlag::LuauStoreReturnTypesAsPackOnAst)
-    {
     if (f->returnAnnotation)
-            visitTypePack(f->returnAnnotation);
+        visitTypeList(*f->returnAnnotation);
-    }
-    else
-    {
-        if (f->returnAnnotation_DEPRECATED)
-            visitTypeList(*f->returnAnnotation_DEPRECATED);
-    }
 
     // TODO: function body can be re-entrant, as in mutations that occurs at the end of the function can also be
     // visible to the beginning of the function, so statically speaking, the body of the function has an exit point
@@ -1073,16 +992,13 @@ DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprFunction* f)
     // g() --> 5
     visit(f->body);
 
-    return {defArena->freshCell(f->debugname, f->location), nullptr};
+    return {defArena->freshCell(), nullptr};
 }
 
 DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprTable* t)
 {
-    DefId tableCell = defArena->freshCell(Symbol{}, t->location);
+    DefId tableCell = defArena->freshCell();
-    if (FFlag::LuauDfgScopeStackNotNull)
     currentScope()->props[tableCell] = {};
-    else
-        currentScope_DEPRECATED()->props[tableCell] = {};
     for (AstExprTable::Item item : t->items)
     {
         DataFlowResult result = visitExpr(item.value);
@@ -1090,12 +1006,7 @@ DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprTable* t)
         {
             visitExpr(item.key);
             if (auto string = item.key->as<AstExprConstantString>())
-            {
-                if (FFlag::LuauDfgScopeStackNotNull)
                 currentScope()->props[tableCell][string->value.data] = result.def;
-                else
-                    currentScope_DEPRECATED()->props[tableCell][string->value.data] = result.def;
-            }
         }
     }
 
@@ -1106,7 +1017,7 @@ DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprUnary* u)
 {
     visitExpr(u->expr);
 
-    return {defArena->freshCell(Symbol{}, u->location), nullptr};
+    return {defArena->freshCell(), nullptr};
 }
 
 DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprBinary* b)
@@ -1114,7 +1025,7 @@ DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprBinary* b)
     visitExpr(b->left);
     visitExpr(b->right);
 
-    return {defArena->freshCell(Symbol{}, b->location), nullptr};
+    return {defArena->freshCell(), nullptr};
 }
 
 DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprTypeAssertion* t)
@@ -1131,7 +1042,7 @@ DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprIfElse* i)
     visitExpr(i->trueExpr);
     visitExpr(i->falseExpr);
 
-    return {defArena->freshCell(Symbol{}, i->location), nullptr};
+    return {defArena->freshCell(), nullptr};
 }
 
 DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprInterpString* i)
@@ -1139,7 +1050,7 @@ DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprInterpString* i)
     for (AstExpr* e : i->expressions)
         visitExpr(e);
 
-    return {defArena->freshCell(Symbol{}, i->location), nullptr};
+    return {defArena->freshCell(), nullptr};
 }
 
 DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprError* error)
@@ -1150,7 +1061,7 @@ DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprError* error)
     for (AstExpr* e : error->expressions)
         visitExpr(e);
 
-    return {defArena->freshCell(Symbol{}, error->location), nullptr};
+    return {defArena->freshCell(), nullptr};
 }
 
 void DataFlowGraphBuilder::visitLValue(AstExpr* e, DefId incomingDef)
@@ -1176,12 +1087,12 @@ void DataFlowGraphBuilder::visitLValue(AstExpr* e, DefId incomingDef)
 
 DefId DataFlowGraphBuilder::visitLValue(AstExprLocal* l, DefId incomingDef)
 {
-    DfgScope* scope = FFlag::LuauDfgScopeStackNotNull ? currentScope() : currentScope_DEPRECATED();
+    DfgScope* scope = currentScope();
 
     // In order to avoid alias tracking, we need to clip the reference to the parent def.
-    if (scope->canUpdateDefinition(l->local) && !(FFlag::LuauDoNotAddUpvalueTypesToLocalType && l->upvalue))
+    if (scope->canUpdateDefinition(l->local))
     {
-        DefId updated = defArena->freshCell(l->local, l->location, containsSubscriptedDefinition(incomingDef));
+        DefId updated = defArena->freshCell(containsSubscriptedDefinition(incomingDef));
         scope->bindings[l->local] = updated;
         captures[l->local].allVersions.push_back(updated);
         return updated;
@@ -1192,12 +1103,12 @@ DefId DataFlowGraphBuilder::visitLValue(AstExprLocal* l, DefId incomingDef)
 
 DefId DataFlowGraphBuilder::visitLValue(AstExprGlobal* g, DefId incomingDef)
 {
-    DfgScope* scope = FFlag::LuauDfgScopeStackNotNull ? currentScope() : currentScope_DEPRECATED();
+    DfgScope* scope = currentScope();
 
     // In order to avoid alias tracking, we need to clip the reference to the parent def.
     if (scope->canUpdateDefinition(g->name))
     {
-        DefId updated = defArena->freshCell(g->name, g->location, containsSubscriptedDefinition(incomingDef));
+        DefId updated = defArena->freshCell(containsSubscriptedDefinition(incomingDef));
         scope->bindings[g->name] = updated;
         captures[g->name].allVersions.push_back(updated);
         return updated;
@@ -1210,10 +1121,10 @@ DefId DataFlowGraphBuilder::visitLValue(AstExprIndexName* i, DefId incomingDef)
 {
     DefId parentDef = visitExpr(i->expr).def;
 
-    DfgScope* scope = FFlag::LuauDfgScopeStackNotNull ? currentScope() : currentScope_DEPRECATED();
+    DfgScope* scope = currentScope();
     if (scope->canUpdateDefinition(parentDef, i->index.value))
     {
-        DefId updated = defArena->freshCell(i->index, i->location, containsSubscriptedDefinition(incomingDef));
+        DefId updated = defArena->freshCell(containsSubscriptedDefinition(incomingDef));
         scope->props[parentDef][i->index.value] = updated;
         return updated;
     }
@@ -1226,12 +1137,12 @@ DefId DataFlowGraphBuilder::visitLValue(AstExprIndexExpr* i, DefId incomingDef)
     DefId parentDef = visitExpr(i->expr).def;
     visitExpr(i->index);
 
-    DfgScope* scope = FFlag::LuauDfgScopeStackNotNull ? currentScope() : currentScope_DEPRECATED();
+    DfgScope* scope = currentScope();
     if (auto string = i->index->as<AstExprConstantString>())
     {
         if (scope->canUpdateDefinition(parentDef, string->value.data))
         {
-            DefId updated = defArena->freshCell(Symbol{}, i->location, containsSubscriptedDefinition(incomingDef));
+            DefId updated = defArena->freshCell(containsSubscriptedDefinition(incomingDef));
             scope->props[parentDef][string->value.data] = updated;
             return updated;
         }
@@ -1239,7 +1150,7 @@ DefId DataFlowGraphBuilder::visitLValue(AstExprIndexExpr* i, DefId incomingDef)
             return visitExpr(static_cast<AstExpr*>(i)).def;
     }
     else
-        return defArena->freshCell(Symbol{}, i->location, /*subscripted=*/true);
+        return defArena->freshCell(/*subscripted=*/true);
 }
 
 DefId DataFlowGraphBuilder::visitLValue(AstExprError* error, DefId incomingDef)
@@ -1303,10 +1214,7 @@ void DataFlowGraphBuilder::visitType(AstTypeFunction* f)
     visitGenerics(f->generics);
     visitGenericPacks(f->genericPacks);
     visitTypeList(f->argTypes);
-    if (FFlag::LuauStoreReturnTypesAsPackOnAst)
+    visitTypeList(f->returnTypes);
-        visitTypePack(f->returnTypes);
-    else
-        visitTypeList(f->returnTypes_DEPRECATED);
 }
 
 void DataFlowGraphBuilder::visitType(AstTypeTypeof* t)

Analysis/src/Def.cpp

@@ -36,9 +36,9 @@ void collectOperands(DefId def, std::vector<DefId>* operands)
     }
 }
 
-DefId DefArena::freshCell(Symbol sym, Location location, bool subscripted)
+DefId DefArena::freshCell(bool subscripted)
 {
-    return NotNull{allocator.allocate(Def{Cell{subscripted}, sym, location})};
+    return NotNull{allocator.allocate(Def{Cell{subscripted}})};
 }
 
 DefId DefArena::phi(DefId a, DefId b)

Analysis/src/Differ.cpp

@@ -277,7 +277,7 @@ static DifferResult diffSingleton(DifferEnvironment& env, TypeId left, TypeId ri
 static DifferResult diffFunction(DifferEnvironment& env, TypeId left, TypeId right);
 static DifferResult diffGeneric(DifferEnvironment& env, TypeId left, TypeId right);
 static DifferResult diffNegation(DifferEnvironment& env, TypeId left, TypeId right);
-static DifferResult diffExternType(DifferEnvironment& env, TypeId left, TypeId right);
+static DifferResult diffClass(DifferEnvironment& env, TypeId left, TypeId right);
 struct FindSeteqCounterexampleResult
 {
     // nullopt if no counterexample found
@@ -481,14 +481,14 @@ static DifferResult diffNegation(DifferEnvironment& env, TypeId left, TypeId rig
     return differResult;
 }
 
-static DifferResult diffExternType(DifferEnvironment& env, TypeId left, TypeId right)
+static DifferResult diffClass(DifferEnvironment& env, TypeId left, TypeId right)
 {
-    const ExternType* leftExternType = get<ExternType>(left);
+    const ClassType* leftClass = get<ClassType>(left);
-    const ExternType* rightExternType = get<ExternType>(right);
+    const ClassType* rightClass = get<ClassType>(right);
-    LUAU_ASSERT(leftExternType);
+    LUAU_ASSERT(leftClass);
-    LUAU_ASSERT(rightExternType);
+    LUAU_ASSERT(rightClass);
 
-    if (leftExternType == rightExternType)
+    if (leftClass == rightClass)
     {
         return DifferResult{};
     }
@@ -651,9 +651,9 @@ static DifferResult diffUsingEnv(DifferEnvironment& env, TypeId left, TypeId rig
         {
             return diffNegation(env, left, right);
         }
-        else if (auto lc = get<ExternType>(left))
+        else if (auto lc = get<ClassType>(left))
         {
-            return diffExternType(env, left, right);
+            return diffClass(env, left, right);
         }
 
         throw InternalCompilerError{"Unimplemented Simple TypeId variant for diffing"};
@@ -960,7 +960,7 @@ bool isSimple(TypeId ty)
 {
     ty = follow(ty);
     // TODO: think about GenericType, etc.
-    return get<PrimitiveType>(ty) || get<SingletonType>(ty) || get<AnyType>(ty) || get<NegationType>(ty) || get<ExternType>(ty) ||
+    return get<PrimitiveType>(ty) || get<SingletonType>(ty) || get<AnyType>(ty) || get<NegationType>(ty) || get<ClassType>(ty) ||
            get<UnknownType>(ty) || get<NeverType>(ty);
 }
 

Analysis/src/EmbeddedBuiltinDefinitions.cpp

@@ -1,8 +1,7 @@
 // This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
 #include "Luau/BuiltinDefinitions.h"
 
-LUAU_FASTFLAG(LuauDeclareExternType)
+LUAU_FASTFLAGVARIABLE(LuauDebugInfoDefn)
-LUAU_FASTFLAG(LuauTypeFunOptional)
 
 namespace Luau
 {
@@ -216,6 +215,15 @@ declare debug: {
 
 )BUILTIN_SRC";
 
+static const std::string kBuiltinDefinitionDebugSrc_DEPRECATED = R"BUILTIN_SRC(
+
+declare debug: {
+    info: (<R...>(thread: thread, level: number, options: string) -> R...) & (<R...>(level: number, options: string) -> R...) & (<A..., R1..., R2...>(func: (A...) -> R1..., options: string) -> R2...),
+    traceback: ((message: string?, level: number?) -> string) & ((thread: thread, message: string?, level: number?) -> string),
+}
+
+)BUILTIN_SRC";
+
 static const std::string kBuiltinDefinitionUtf8Src = R"BUILTIN_SRC(
 
 declare utf8: {
@@ -262,37 +270,7 @@ declare buffer: {
 
 )BUILTIN_SRC";
 
-static const std::string kBuiltinDefinitionVectorSrc = (FFlag::LuauDeclareExternType)
+static const std::string kBuiltinDefinitionVectorSrc = R"BUILTIN_SRC(
-    ? R"BUILTIN_SRC(
-
--- While vector would have been better represented as a built-in primitive type, type solver extern type handling covers most of the properties
-declare extern type vector with
-    x: number
-    y: number
-    z: number
-end
-
-declare vector: {
-    create: @checked (x: number, y: number, z: number?) -> vector,
-    magnitude: @checked (vec: vector) -> number,
-    normalize: @checked (vec: vector) -> vector,
-    cross: @checked (vec1: vector, vec2: vector) -> vector,
-    dot: @checked (vec1: vector, vec2: vector) -> number,
-    angle: @checked (vec1: vector, vec2: vector, axis: vector?) -> number,
-    floor: @checked (vec: vector) -> vector,
-    ceil: @checked (vec: vector) -> vector,
-    abs: @checked (vec: vector) -> vector,
-    sign: @checked (vec: vector) -> vector,
-    clamp: @checked (vec: vector, min: vector, max: vector) -> vector,
-    max: @checked (vector, ...vector) -> vector,
-    min: @checked (vector, ...vector) -> vector,
-
-    zero: vector,
-    one: vector,
-}
-
-)BUILTIN_SRC"
-    : R"BUILTIN_SRC(
 
 -- While vector would have been better represented as a built-in primitive type, type solver class handling covers most of the properties
 declare class vector
@@ -331,7 +309,7 @@ std::string getBuiltinDefinitionSource()
     result += kBuiltinDefinitionOsSrc;
     result += kBuiltinDefinitionCoroutineSrc;
     result += kBuiltinDefinitionTableSrc;
-    result += kBuiltinDefinitionDebugSrc;
+    result += FFlag::LuauDebugInfoDefn ? kBuiltinDefinitionDebugSrc : kBuiltinDefinitionDebugSrc_DEPRECATED;
     result += kBuiltinDefinitionUtf8Src;
     result += kBuiltinDefinitionBufferSrc;
     result += kBuiltinDefinitionVectorSrc;
@@ -340,11 +318,11 @@ std::string getBuiltinDefinitionSource()
 }
 
 // TODO: split into separate tagged unions when the new solver can appropriately handle that.
-static const std::string kBuiltinDefinitionTypeMethodSrc = R"BUILTIN_SRC(
+static const std::string kBuiltinDefinitionTypesSrc = R"BUILTIN_SRC(
 
 export type type = {
     tag: "nil" | "unknown" | "never" | "any" | "boolean" | "number" | "string" | "buffer" | "thread" |
-         "singleton" | "negation" | "union" | "intersection" | "table" | "function" | "class" | "generic",
+         "singleton" | "negation" | "union" | "intesection" | "table" | "function" | "class" | "generic",
 
     is: (self: type, arg: string) -> boolean,
 
@@ -391,10 +369,6 @@ export type type = {
     ispack: (self: type) -> boolean,
 }
 
-)BUILTIN_SRC";
-
-static const std::string kBuiltinDefinitionTypesLibSrc = R"BUILTIN_SRC(
-
 declare types: {
     unknown: type,
     never: type,
@@ -414,44 +388,12 @@ declare types: {
     newfunction: @checked (parameters: { head: {type}?, tail: type? }?, returns: { head: {type}?, tail: type? }?, generics: {type}?) -> type,
     copy: @checked (arg: type) -> type,
 }
+
 )BUILTIN_SRC";
 
-static const std::string kBuiltinDefinitionTypesLibWithOptionalSrc = R"BUILTIN_SRC(
-
-declare types: {
-    unknown: type,
-    never: type,
-    any: type,
-    boolean: type,
-    number: type,
-    string: type,
-    thread: type,
-    buffer: type,
-
-    singleton: @checked (arg: string | boolean | nil) -> type,
-    optional: @checked (arg: type) -> type,
-    generic: @checked (name: string, ispack: boolean?) -> type,
-    negationof: @checked (arg: type) -> type,
-    unionof: @checked (...type) -> type,
-    intersectionof: @checked (...type) -> type,
-    newtable: @checked (props: {[type]: type} | {[type]: { read: type, write: type } } | nil, indexer: { index: type, readresult: type, writeresult: type }?, metatable: type?) -> type,
-    newfunction: @checked (parameters: { head: {type}?, tail: type? }?, returns: { head: {type}?, tail: type? }?, generics: {type}?) -> type,
-    copy: @checked (arg: type) -> type,
-}
-)BUILTIN_SRC";
-
-
 std::string getTypeFunctionDefinitionSource()
 {
-
+    return kBuiltinDefinitionTypesSrc;
-    std::string result = kBuiltinDefinitionTypeMethodSrc;
-
-    if (FFlag::LuauTypeFunOptional)
-        result += kBuiltinDefinitionTypesLibWithOptionalSrc;
-    else
-        result += kBuiltinDefinitionTypesLibSrc;
-
-    return result;
 }
 
 } // namespace Luau

Analysis/src/EqSatSimplification.cpp

@@ -330,9 +330,9 @@ Id toId(
         return egraph.add(TOpaque{ty});
     else if (get<FunctionType>(ty))
         return egraph.add(TFunction{ty});
-    else if (ty == builtinTypes->externType)
+    else if (ty == builtinTypes->classType)
         return egraph.add(TTopClass{});
-    else if (get<ExternType>(ty))
+    else if (get<ClassType>(ty))
         return egraph.add(TClass{ty});
     else if (get<AnyType>(ty))
         return egraph.add(TAny{});
@@ -752,7 +752,7 @@ TypeId fromId(
     else if (node.get<TTopTable>())
         return builtinTypes->tableType;
     else if (node.get<TTopClass>())
-        return builtinTypes->externType;
+        return builtinTypes->classType;
     else if (node.get<TBuffer>())
         return builtinTypes->bufferType;
     else if (auto opaque = node.get<TOpaque>())
@@ -1007,7 +1007,7 @@ static std::string getNodeName(const StringCache& strings, const EType& node)
         return "\xe2\x88\xa9";
     else if (auto cls = node.get<TClass>())
     {
-        const ExternType* ct = get<ExternType>(cls->value());
+        const ClassType* ct = get<ClassType>(cls->value());
         LUAU_ASSERT(ct);
         return ct->name;
     }
@@ -1177,12 +1177,12 @@ enum SubclassRelationship
 
 static SubclassRelationship relateClasses(const TClass* leftClass, const TClass* rightClass)
 {
-    const ExternType* leftExternType = Luau::get<ExternType>(leftClass->value());
+    const ClassType* leftClassType = Luau::get<ClassType>(leftClass->value());
-    const ExternType* rightExternType = Luau::get<ExternType>(rightClass->value());
+    const ClassType* rightClassType = Luau::get<ClassType>(rightClass->value());
 
-    if (isSubclass(leftExternType, rightExternType))
+    if (isSubclass(leftClassType, rightClassType))
         return RightSuper;
-    else if (isSubclass(rightExternType, leftExternType))
+    else if (isSubclass(rightClassType, leftClassType))
         return LeftSuper;
     else
         return Unrelated;

Analysis/src/Error.cpp

@@ -18,7 +18,7 @@
 #include <unordered_set>
 
 LUAU_FASTINTVARIABLE(LuauIndentTypeMismatchMaxTypeLength, 10)
-LUAU_FASTFLAG(DebugLuauGreedyGeneralization)
+LUAU_FASTFLAG(LuauNonStrictFuncDefErrorFix)
 
 static std::string wrongNumberOfArgsString(
     size_t expectedCount,
@@ -70,7 +70,7 @@ namespace Luau
 {
 
 // this list of binary operator type functions is used for better stringification of type functions errors
-static const std::unordered_map<std::string, const char*> DEPRECATED_kBinaryOps{
+static const std::unordered_map<std::string, const char*> kBinaryOps{
     {"add", "+"},
     {"sub", "-"},
     {"mul", "*"},
@@ -86,27 +86,12 @@ static const std::unordered_map<std::string, const char*> DEPRECATED_kBinaryOps{
     {"eq", "== or ~="}
 };
 
-static const std::unordered_map<std::string, const char*> kBinaryOps{
-    {"add", "+"},
-    {"sub", "-"},
-    {"mul", "*"},
-    {"div", "/"},
-    {"idiv", "//"},
-    {"pow", "^"},
-    {"mod", "%"},
-    {"concat", ".."},
-    {"lt", "< or >="},
-    {"le", "<= or >"},
-    {"eq", "== or ~="}
-};
-
 // this list of unary operator type functions is used for better stringification of type functions errors
 static const std::unordered_map<std::string, const char*> kUnaryOps{{"unm", "-"}, {"len", "#"}, {"not", "not"}};
 
 // this list of type functions will receive a special error indicating that the user should file a bug on the GitHub repository
 // putting a type function in this list indicates that it is expected to _always_ reduce
-static const std::unordered_set<std::string> DEPRECATED_kUnreachableTypeFunctions{"refine", "singleton", "union", "intersect"};
+static const std::unordered_set<std::string> kUnreachableTypeFunctions{"refine", "singleton", "union", "intersect"};
-static const std::unordered_set<std::string> kUnreachableTypeFunctions{"refine", "singleton", "union", "intersect", "and", "or"};
 
 struct ErrorConverter
 {
@@ -203,7 +188,7 @@ struct ErrorConverter
         TypeId t = follow(e.table);
         if (get<TableType>(t))
             return "Key '" + e.key + "' not found in table '" + Luau::toString(t) + "'";
-        else if (get<ExternType>(t))
+        else if (get<ClassType>(t))
             return "Key '" + e.key + "' not found in class '" + Luau::toString(t) + "'";
         else
             return "Type '" + Luau::toString(e.table) + "' does not have key '" + e.key + "'";
@@ -371,7 +356,7 @@ struct ErrorConverter
         std::string s = "Key '" + e.key + "' not found in ";
 
         TypeId t = follow(e.table);
-        if (get<ExternType>(t))
+        if (get<ClassType>(t))
             s += "class";
         else
             s += "table";
@@ -402,8 +387,8 @@ struct ErrorConverter
         std::optional<TypeId> metatable;
         if (const MetatableType* mtType = get<MetatableType>(type))
             metatable = mtType->metatable;
-        else if (const ExternType* externType = get<ExternType>(type))
+        else if (const ClassType* classType = get<ClassType>(type))
-            metatable = externType->metatable;
+            metatable = classType->metatable;
 
         if (!metatable)
             return std::nullopt;
@@ -611,7 +596,7 @@ struct ErrorConverter
         return ss;
     }
 
-    std::string operator()(const DynamicPropertyLookupOnExternTypesUnsafe& e) const
+    std::string operator()(const DynamicPropertyLookupOnClassesUnsafe& e) const
     {
         return "Attempting a dynamic property access on type '" + Luau::toString(e.ty) + "' is unsafe and may cause exceptions at runtime";
     }
@@ -621,7 +606,7 @@ struct ErrorConverter
         auto tfit = get<TypeFunctionInstanceType>(e.ty);
         LUAU_ASSERT(tfit); // Luau analysis has actually done something wrong if this type is not a type function.
         if (!tfit)
-            return "Internal error: Unexpected type " + Luau::toString(e.ty) + " flagged as an uninhabited type function.";
+            return "Unexpected type " + Luau::toString(e.ty) + " flagged as an uninhabited type function.";
 
         // unary operators
         if (auto unaryString = kUnaryOps.find(tfit->function->name); unaryString != kUnaryOps.end())
@@ -658,8 +643,7 @@ struct ErrorConverter
         }
 
         // binary operators
-        const auto binaryOps = FFlag::DebugLuauGreedyGeneralization ? kBinaryOps : DEPRECATED_kBinaryOps;
+        if (auto binaryString = kBinaryOps.find(tfit->function->name); binaryString != kBinaryOps.end())
-        if (auto binaryString = binaryOps.find(tfit->function->name); binaryString != binaryOps.end())
         {
             std::string result = "Operator '" + std::string(binaryString->second) + "' could not be applied to operands of types ";
 
@@ -713,7 +697,7 @@ struct ErrorConverter
                        "'";
         }
 
-        if ((FFlag::DebugLuauGreedyGeneralization ? kUnreachableTypeFunctions : DEPRECATED_kUnreachableTypeFunctions).count(tfit->function->name))
+        if (kUnreachableTypeFunctions.count(tfit->function->name))
         {
             return "Type function instance " + Luau::toString(e.ty) + " is uninhabited\n" +
                    "This is likely to be a bug, please report it at https://github.com/luau-lang/luau/issues";
@@ -772,7 +756,7 @@ struct ErrorConverter
 
     std::string operator()(const NonStrictFunctionDefinitionError& e) const
     {
-        if (e.functionName.empty())
+        if (FFlag::LuauNonStrictFuncDefErrorFix && e.functionName.empty())
         {
             return "Argument " + e.argument + " with type '" + toString(e.argumentType) + "' is used in a way that will run time error";
         }
@@ -819,11 +803,6 @@ struct ErrorConverter
         return e.message;
     }
 
-    std::string operator()(const ReservedIdentifier& e) const
-    {
-        return e.name + " cannot be used as an identifier for a type function or alias";
-    }
-
     std::string operator()(const CannotAssignToNever& e) const
     {
         std::string result = "Cannot assign a value of type " + toString(e.rhsType) + " to a field of type never";
@@ -1149,7 +1128,7 @@ bool TypePackMismatch::operator==(const TypePackMismatch& rhs) const
     return *wantedTp == *rhs.wantedTp && *givenTp == *rhs.givenTp;
 }
 
-bool DynamicPropertyLookupOnExternTypesUnsafe::operator==(const DynamicPropertyLookupOnExternTypesUnsafe& rhs) const
+bool DynamicPropertyLookupOnClassesUnsafe::operator==(const DynamicPropertyLookupOnClassesUnsafe& rhs) const
 {
     return ty == rhs.ty;
 }
@@ -1211,11 +1190,6 @@ bool UserDefinedTypeFunctionError::operator==(const UserDefinedTypeFunctionError
     return message == rhs.message;
 }
 
-bool ReservedIdentifier::operator==(const ReservedIdentifier& rhs) const
-{
-    return name == rhs.name;
-}
-
 bool CannotAssignToNever::operator==(const CannotAssignToNever& rhs) const
 {
     if (cause.size() != rhs.cause.size())
@@ -1391,7 +1365,7 @@ void copyError(T& e, TypeArena& destArena, CloneState& cloneState)
         e.wantedTp = clone(e.wantedTp);
         e.givenTp = clone(e.givenTp);
     }
-    else if constexpr (std::is_same_v<T, DynamicPropertyLookupOnExternTypesUnsafe>)
+    else if constexpr (std::is_same_v<T, DynamicPropertyLookupOnClassesUnsafe>)
         e.ty = clone(e.ty);
     else if constexpr (std::is_same_v<T, UninhabitedTypeFunction>)
         e.ty = clone(e.ty);
@@ -1435,9 +1409,6 @@ void copyError(T& e, TypeArena& destArena, CloneState& cloneState)
         for (auto& ty : e.cause)
             ty = clone(ty);
     }
-    else if constexpr (std::is_same_v<T, ReservedIdentifier>)
-    {
-    }
     else
         static_assert(always_false_v<T>, "Non-exhaustive type switch");
 }

Analysis/src/FileResolver.cpp

@@ -10,6 +10,10 @@
 #include <string_view>
 #include <utility>
 
+LUAU_FASTFLAGVARIABLE(LuauExposeRequireByStringAutocomplete)
+LUAU_FASTFLAGVARIABLE(LuauEscapeCharactersInRequireSuggestions)
+LUAU_FASTFLAGVARIABLE(LuauHideImpossibleRequireSuggestions)
+
 namespace Luau
 {
 
@@ -18,10 +22,13 @@ static std::optional<RequireSuggestions> processRequireSuggestions(std::optional
     if (!suggestions)
         return suggestions;
 
+    if (FFlag::LuauEscapeCharactersInRequireSuggestions)
+    {
         for (RequireSuggestion& suggestion : *suggestions)
         {
             suggestion.fullPath = escape(suggestion.fullPath);
         }
+    }
 
     return suggestions;
 }
@@ -105,11 +112,13 @@ static RequireSuggestions makeSuggestionsFromNode(std::unique_ptr<RequireNode> n
             continue;
 
         std::string pathComponent = child->getPathComponent();
-
+        if (FFlag::LuauHideImpossibleRequireSuggestions)
+        {
             // If path component contains a slash, it cannot be required by string.
             // There's no point suggesting it.
             if (pathComponent.find('/') != std::string::npos)
                 continue;
+        }
 
         RequireSuggestion suggestion;
         suggestion.label = isPartialPath || path.back() == '/' ? child->getLabel() : "/" + child->getLabel();
@@ -154,6 +163,9 @@ std::optional<RequireSuggestions> RequireSuggester::getRequireSuggestions(const
 
 std::optional<RequireSuggestions> FileResolver::getRequireSuggestions(const ModuleName& requirer, const std::optional<std::string>& path) const
 {
+    if (!FFlag::LuauExposeRequireByStringAutocomplete)
+        return std::nullopt;
+
     return requireSuggester ? requireSuggester->getRequireSuggestions(requirer, path) : std::nullopt;
 }
 

Analysis/src/FragmentAutocomplete.cpp

@@ -22,25 +22,26 @@
 #include "Luau/Module.h"
 #include "Luau/Clone.h"
 #include "AutocompleteCore.h"
-#include <optional>
 
 LUAU_FASTINT(LuauTypeInferRecursionLimit);
 LUAU_FASTINT(LuauTypeInferIterationLimit);
 LUAU_FASTINT(LuauTarjanChildLimit)
+LUAU_FASTFLAG(LuauAutocompleteRefactorsForIncrementalAutocomplete)
 
-LUAU_FASTFLAGVARIABLE(DebugLogFragmentsFromAutocomplete)
+LUAU_FASTFLAGVARIABLE(LuauIncrementalAutocompleteBugfixes)
+LUAU_FASTFLAGVARIABLE(LuauMixedModeDefFinderTraversesTypeOf)
+LUAU_FASTFLAGVARIABLE(LuauCloneIncrementalModule)
+LUAU_FASTFLAGVARIABLE(LogFragmentsFromAutocomplete)
 LUAU_FASTFLAGVARIABLE(LuauBetterCursorInCommentDetection)
 LUAU_FASTFLAGVARIABLE(LuauAllFreeTypesHaveScopes)
+LUAU_FASTFLAGVARIABLE(LuauFragmentAcSupportsReporter)
 LUAU_FASTFLAGVARIABLE(LuauPersistConstraintGenerationScopes)
+LUAU_FASTFLAG(LuauModuleHoldsAstRoot)
 LUAU_FASTFLAGVARIABLE(LuauCloneTypeAliasBindings)
+LUAU_FASTFLAGVARIABLE(LuauCloneReturnTypePack)
 LUAU_FASTFLAGVARIABLE(LuauIncrementalAutocompleteDemandBasedCloning)
 LUAU_FASTFLAG(LuauUserTypeFunTypecheck)
 LUAU_FASTFLAGVARIABLE(LuauFragmentNoTypeFunEval)
-LUAU_FASTFLAGVARIABLE(LuauBetterScopeSelection)
-LUAU_FASTFLAGVARIABLE(LuauBlockDiffFragmentSelection)
-LUAU_FASTFLAGVARIABLE(LuauFragmentAcMemoryLeak)
-LUAU_FASTFLAGVARIABLE(LuauGlobalVariableModuleIsolation)
-LUAU_FASTFLAG(LuauStoreReturnTypesAsPackOnAst)
 
 namespace
 {
@@ -86,437 +87,6 @@ void cloneModuleMap(
     }
 }
 
-static std::pair<size_t, size_t> getDocumentOffsets(std::string_view src, const Position& startPos, const Position& endPos);
-
-// when typing a function partially, get the span of the first line
-// e.g. local function fn() : ... - typically we want to provide autocomplete results if you're
-// editing type annotations in this range
-Location getFunctionDeclarationExtents(AstExprFunction* exprFn, AstExpr* exprName = nullptr, AstLocal* localName = nullptr)
-{
-    auto fnBegin = exprFn->location.begin;
-    auto fnEnd = exprFn->location.end;
-    if (auto returnAnnot = exprFn->returnAnnotation; FFlag::LuauStoreReturnTypesAsPackOnAst && returnAnnot)
-    {
-        fnEnd = returnAnnot->location.end;
-    }
-    else if (auto returnAnnot = exprFn->returnAnnotation_DEPRECATED; !FFlag::LuauStoreReturnTypesAsPackOnAst && returnAnnot)
-    {
-        if (returnAnnot->tailType)
-            fnEnd = returnAnnot->tailType->location.end;
-        else if (returnAnnot->types.size != 0)
-            fnEnd = returnAnnot->types.data[returnAnnot->types.size - 1]->location.end;
-    }
-    else if (exprFn->args.size != 0)
-    {
-        auto last = exprFn->args.data[exprFn->args.size - 1];
-        if (last->annotation)
-            fnEnd = last->annotation->location.end;
-        else
-            fnEnd = last->location.end;
-    }
-    else if (exprFn->genericPacks.size != 0)
-        fnEnd = exprFn->genericPacks.data[exprFn->genericPacks.size - 1]->location.end;
-    else if (exprFn->generics.size != 0)
-        fnEnd = exprFn->generics.data[exprFn->generics.size - 1]->location.end;
-    else if (exprName)
-        fnEnd = exprName->location.end;
-    else if (localName)
-        fnEnd = localName->location.end;
-    return Location{fnBegin, fnEnd};
-};
-
-Location getAstStatForExtents(AstStatFor* forStat)
-{
-    auto begin = forStat->location.begin;
-    auto end = forStat->location.end;
-    if (forStat->step)
-        end = forStat->step->location.end;
-    else if (forStat->to)
-        end = forStat->to->location.end;
-    else if (forStat->from)
-        end = forStat->from->location.end;
-    else if (forStat->var)
-        end = forStat->var->location.end;
-
-    return Location{begin, end};
-}
-
-Location getFragmentLocation(AstStat* nearestStatement, const Position& cursorPosition)
-{
-    Location empty{cursorPosition, cursorPosition};
-    if (nearestStatement)
-    {
-        Location nonEmpty{nearestStatement->location.begin, cursorPosition};
-        // If your sibling is a do block, do nothing
-        if (auto doEnd = nearestStatement->as<AstStatBlock>())
-            return empty;
-
-        // If you're inside the body of the function and this is your sibling, empty fragment
-        // If you're outside the body (e.g. you're typing stuff out, non-empty)
-        if (auto fn = nearestStatement->as<AstStatFunction>())
-        {
-            auto loc = getFunctionDeclarationExtents(fn->func, fn->name, /* local */ nullptr);
-            if (loc.containsClosed(cursorPosition))
-                return nonEmpty;
-            else if (fn->func->body->location.containsClosed(cursorPosition) || fn->location.end <= cursorPosition)
-                return empty;
-            else if (fn->func->location.contains(cursorPosition))
-                return nonEmpty;
-        }
-
-        if (auto fn = nearestStatement->as<AstStatLocalFunction>())
-        {
-            auto loc = getFunctionDeclarationExtents(fn->func, /* global func */ nullptr, fn->name);
-            if (loc.containsClosed(cursorPosition))
-                return nonEmpty;
-            else if (fn->func->body->location.containsClosed(cursorPosition) || fn->location.end <= cursorPosition)
-                return empty;
-            else if (fn->func->location.contains(cursorPosition))
-                return nonEmpty;
-        }
-
-        if (auto wh = nearestStatement->as<AstStatWhile>())
-        {
-            if (!wh->hasDo)
-                return nonEmpty;
-            else
-                return empty;
-        }
-
-        if (auto forStat = nearestStatement->as<AstStatFor>())
-        {
-            if (!forStat->hasDo)
-                return nonEmpty;
-            else
-                return empty;
-        }
-
-        if (auto forIn = nearestStatement->as<AstStatForIn>())
-        {
-            // If we don't have a do statement
-            if (!forIn->hasDo)
-                return nonEmpty;
-            else
-                return empty;
-        }
-
-        if (auto ifS = nearestStatement->as<AstStatIf>())
-        {
-            auto conditionExtents = Location{ifS->location.begin, ifS->condition->location.end};
-            if (conditionExtents.containsClosed(cursorPosition))
-                return nonEmpty;
-            else if (ifS->thenbody->location.containsClosed(cursorPosition))
-                return empty;
-            else if (auto elseS = ifS->elsebody)
-            {
-                if (auto elseIf = ifS->elsebody->as<AstStatIf>())
-                {
-
-                    if (elseIf->thenbody->hasEnd)
-                        return empty;
-                    else
-                        return {elseS->location.begin, cursorPosition};
-                }
-                return empty;
-            }
-        }
-
-        return nonEmpty;
-    }
-    return empty;
-}
-
-struct NearestStatementFinder : public AstVisitor
-{
-    explicit NearestStatementFinder(const Position& cursorPosition)
-        : cursor(cursorPosition)
-    {
-    }
-
-    bool visit(AstStatBlock* block) override
-    {
-        if (block->location.containsClosed(cursor))
-        {
-            parent = block;
-            for (auto v : block->body)
-            {
-                if (v->location.begin <= cursor)
-                {
-                    nearest = v;
-                }
-            }
-            return true;
-        }
-        else
-            return false;
-    }
-
-    const Position& cursor;
-    AstStat* nearest = nullptr;
-    AstStatBlock* parent = nullptr;
-};
-
-// This struct takes a block found in a updated AST and looks for the corresponding block in a different ast.
-// This is a best effort check - we are looking for the block that is as close in location, ideally the same
-// block as the one from the updated AST
-struct NearestLikelyBlockFinder : public AstVisitor
-{
-    explicit NearestLikelyBlockFinder(NotNull<AstStatBlock> stmtBlockRecentAst)
-        : stmtBlockRecentAst(stmtBlockRecentAst)
-    {
-    }
-
-    bool visit(AstStatBlock* block) override
-    {
-        if (block->location.begin <= stmtBlockRecentAst->location.begin)
-        {
-            if (found)
-            {
-                if (found.value()->location.begin < block->location.begin)
-                    found.emplace(block);
-            }
-            else
-            {
-                found.emplace(block);
-            }
-        }
-
-        return true;
-    }
-    NotNull<AstStatBlock> stmtBlockRecentAst;
-    std::optional<AstStatBlock*> found = std::nullopt;
-};
-
-// Diffs two ast stat blocks. Once at the first difference, consume between that range and the end of the nearest statement
-std::optional<Position> blockDiffStart(AstStatBlock* blockOld, AstStatBlock* blockNew, AstStat* nearestStatementNewAst)
-{
-    AstArray<AstStat*> _old = blockOld->body;
-    AstArray<AstStat*> _new = blockNew->body;
-    size_t oldSize = _old.size;
-    size_t stIndex = 0;
-
-    // We couldn't find a nearest statement
-    if (nearestStatementNewAst == blockNew)
-        return std::nullopt;
-    bool found = false;
-    for (auto st : _new)
-    {
-        if (st == nearestStatementNewAst)
-        {
-            found = true;
-            break;
-        }
-        stIndex++;
-    }
-
-    if (!found)
-        return std::nullopt;
-    // Take care of some easy cases!
-    if (oldSize == 0 && _new.size >= 0)
-        return {_new.data[0]->location.begin};
-
-    if (_new.size < oldSize)
-        return std::nullopt;
-
-    for (size_t i = 0; i < std::min(oldSize, stIndex + 1); i++)
-    {
-        AstStat* oldStat = _old.data[i];
-        AstStat* newStat = _new.data[i];
-
-        bool isSame = oldStat->classIndex == newStat->classIndex && oldStat->location == newStat->location;
-        if (!isSame)
-            return {oldStat->location.begin};
-    }
-
-    if (oldSize <= stIndex)
-        return {_new.data[oldSize]->location.begin};
-
-    return std::nullopt;
-}
-
-
-FragmentRegion getFragmentRegion(AstStatBlock* root, const Position& cursorPosition)
-{
-    NearestStatementFinder nsf{cursorPosition};
-    root->visit(&nsf);
-    AstStatBlock* parent = root;
-    if (nsf.parent)
-        parent = nsf.parent;
-    return FragmentRegion{getFragmentLocation(nsf.nearest, cursorPosition), nsf.nearest, parent};
-};
-
-FragmentRegion getFragmentRegionWithBlockDiff(AstStatBlock* stale, AstStatBlock* fresh, const Position& cursorPos)
-{
-    // Visit the new ast
-    NearestStatementFinder nsf{cursorPos};
-    fresh->visit(&nsf);
-    // parent must always be non-null
-    NotNull<AstStatBlock> parent{nsf.parent ? nsf.parent : fresh};
-    NotNull<AstStat> nearest{nsf.nearest ? nsf.nearest : fresh};
-    // Grab the same start block in the stale ast
-    NearestLikelyBlockFinder lsf{parent};
-    stale->visit(&lsf);
-
-    if (auto sameBlock = lsf.found)
-    {
-        if (std::optional<Position> fd = blockDiffStart(*sameBlock, parent, nearest))
-            return FragmentRegion{Location{*fd, cursorPos}, nearest, parent};
-    }
-    return FragmentRegion{getFragmentLocation(nsf.nearest, cursorPos), nearest, parent};
-}
-
-FragmentAutocompleteAncestryResult findAncestryForFragmentParse(AstStatBlock* stale, const Position& cursorPos, AstStatBlock* lastGoodParse)
-{
-    // the freshest ast can sometimes be null if the parse was bad.
-    if (lastGoodParse == nullptr)
-        return {};
-    FragmentRegion region = FFlag::LuauBlockDiffFragmentSelection ? getFragmentRegionWithBlockDiff(stale, lastGoodParse, cursorPos)
-                                                                  : getFragmentRegion(lastGoodParse, cursorPos);
-    std::vector<AstNode*> ancestry = findAncestryAtPositionForAutocomplete(stale, cursorPos);
-    LUAU_ASSERT(ancestry.size() >= 1);
-    // We should only pick up locals that are before the region
-    DenseHashMap<AstName, AstLocal*> localMap{AstName()};
-    std::vector<AstLocal*> localStack;
-
-    for (AstNode* node : ancestry)
-    {
-        if (auto block = node->as<AstStatBlock>())
-        {
-            for (auto stat : block->body)
-            {
-                if (stat->location.begin < region.fragmentLocation.begin)
-                {
-                    // This statement precedes the current one
-                    if (auto statLoc = stat->as<AstStatLocal>())
-                    {
-                        for (auto v : statLoc->vars)
-                        {
-                            localStack.push_back(v);
-                            localMap[v->name] = v;
-                        }
-                    }
-                    else if (auto locFun = stat->as<AstStatLocalFunction>())
-                    {
-                        localStack.push_back(locFun->name);
-                        localMap[locFun->name->name] = locFun->name;
-                        if (locFun->location.contains(cursorPos))
-                        {
-                            for (AstLocal* loc : locFun->func->args)
-                            {
-                                localStack.push_back(loc);
-                                localMap[loc->name] = loc;
-                            }
-                        }
-                    }
-                    else if (auto globFun = stat->as<AstStatFunction>())
-                    {
-                        if (globFun->location.contains(cursorPos))
-                        {
-                            for (AstLocal* loc : globFun->func->args)
-                            {
-                                localStack.push_back(loc);
-                                localMap[loc->name] = loc;
-                            }
-                        }
-                    }
-                    else if (auto typeFun = stat->as<AstStatTypeFunction>(); typeFun)
-                    {
-                        if (typeFun->location.contains(cursorPos))
-                        {
-                            for (AstLocal* loc : typeFun->body->args)
-                            {
-                                localStack.push_back(loc);
-                                localMap[loc->name] = loc;
-                            }
-                        }
-                    }
-                    else if (auto forL = stat->as<AstStatFor>())
-                    {
-                        if (forL->var && forL->var->location.begin < region.fragmentLocation.begin)
-                        {
-                            localStack.push_back(forL->var);
-                            localMap[forL->var->name] = forL->var;
-                        }
-                    }
-                    else if (auto forIn = stat->as<AstStatForIn>())
-                    {
-                        for (auto var : forIn->vars)
-                        {
-                            if (var->location.begin < region.fragmentLocation.begin)
-                            {
-                                localStack.push_back(var);
-                                localMap[var->name] = var;
-                            }
-                        }
-                    }
-                }
-            }
-        }
-
-        if (auto exprFunc = node->as<AstExprFunction>())
-        {
-            if (exprFunc->location.contains(cursorPos))
-            {
-                for (auto v : exprFunc->args)
-                {
-                    localStack.push_back(v);
-                    localMap[v->name] = v;
-                }
-            }
-        }
-    }
-
-    return {localMap, localStack, ancestry, region.nearestStatement, region.parentBlock, region.fragmentLocation};
-}
-
-std::optional<FragmentParseResult> parseFragment(
-    AstStatBlock* stale,
-    AstStatBlock* mostRecentParse,
-    AstNameTable* names,
-    std::string_view src,
-    const Position& cursorPos,
-    std::optional<Position> fragmentEndPosition
-)
-{
-    if (mostRecentParse == nullptr)
-        return std::nullopt;
-    FragmentAutocompleteAncestryResult result = findAncestryForFragmentParse(stale, cursorPos, mostRecentParse);
-    AstStat* nearestStatement = result.nearestStatement;
-
-    Position startPos = result.fragmentSelectionRegion.begin;
-    Position endPos = fragmentEndPosition.value_or(result.fragmentSelectionRegion.end);
-
-    auto [offsetStart, parseLength] = getDocumentOffsets(src, startPos, endPos);
-    const char* srcStart = src.data() + offsetStart;
-    std::string_view dbg = src.substr(offsetStart, parseLength);
-    FragmentParseResult fragmentResult;
-    fragmentResult.fragmentToParse = std::string(dbg);
-    // For the duration of the incremental parse, we want to allow the name table to re-use duplicate names
-    if (FFlag::DebugLogFragmentsFromAutocomplete)
-        logLuau("Fragment Selected", dbg);
-
-    ParseOptions opts;
-    opts.allowDeclarationSyntax = false;
-    opts.captureComments = true;
-    opts.parseFragment = FragmentParseResumeSettings{std::move(result.localMap), std::move(result.localStack), startPos};
-    ParseResult p = Luau::Parser::parse(srcStart, parseLength, *names, *fragmentResult.alloc, opts);
-    // This means we threw a ParseError and we should decline to offer autocomplete here.
-    if (p.root == nullptr)
-        return std::nullopt;
-
-    std::vector<AstNode*> fabricatedAncestry = std::move(result.ancestry);
-    std::vector<AstNode*> fragmentAncestry = findAncestryAtPositionForAutocomplete(p.root, cursorPos);
-    fabricatedAncestry.insert(fabricatedAncestry.end(), fragmentAncestry.begin(), fragmentAncestry.end());
-    if (nearestStatement == nullptr)
-        nearestStatement = p.root;
-    fragmentResult.root = p.root;
-    fragmentResult.ancestry = std::move(fabricatedAncestry);
-    fragmentResult.nearestStatement = nearestStatement;
-    fragmentResult.commentLocations = std::move(p.commentLocations);
-    fragmentResult.scopePos = result.parentBlock->location.begin;
-    return fragmentResult;
-}
-
 struct UsageFinder : public AstVisitor
 {
 
@@ -544,11 +114,6 @@ struct UsageFinder : public AstVisitor
         return true;
     }
 
-    bool visit(AstTypePack* node) override
-    {
-        return FFlag::LuauStoreReturnTypesAsPackOnAst;
-    }
-
     bool visit(AstStatTypeAlias* alias) override
     {
         declaredAliases.insert(std::string(alias->name.value));
@@ -576,32 +141,12 @@ struct UsageFinder : public AstVisitor
         return true;
     }
 
-    bool visit(AstExprGlobal* global) override
-    {
-        if (FFlag::LuauGlobalVariableModuleIsolation)
-            globalDefsToPrePopulate.emplace_back(global->name, dfg->getDef(global));
-        return true;
-    }
-
-    bool visit(AstStatFunction* function) override
-    {
-        if (FFlag::LuauGlobalVariableModuleIsolation)
-        {
-            if (AstExprGlobal* g = function->name->as<AstExprGlobal>())
-                globalFunctionsReferenced.emplace_back(g->name);
-        }
-
-        return true;
-    }
-
     NotNull<DataFlowGraph> dfg;
     DenseHashSet<Name> declaredAliases{""};
     std::vector<std::pair<const Def*, AstLocal*>> localBindingsReferenced;
     DenseHashSet<const Def*> mentionedDefs{nullptr};
     std::vector<Name> referencedBindings{""};
     std::vector<std::pair<Name, Name>> referencedImportedBindings{{"", ""}};
-    std::vector<std::pair<AstName, const Def*>> globalDefsToPrePopulate;
-    std::vector<AstName> globalFunctionsReferenced;
 };
 
 // Runs the `UsageFinder` traversal on the fragment and grabs all of the types that are
@@ -613,7 +158,6 @@ void cloneTypesFromFragment(
     const ModulePtr& staleModule,
     NotNull<TypeArena> destArena,
     NotNull<DataFlowGraph> dfg,
-    NotNull<BuiltinTypes> builtins,
     AstStatBlock* program,
     Scope* destScope
 )
@@ -644,13 +188,6 @@ void cloneTypesFromFragment(
             destScope->lvalueTypes[d] = Luau::cloneIncremental(pair->second.typeId, *destArena, cloneState, destScope);
             destScope->bindings[pair->first] = Luau::cloneIncremental(pair->second, *destArena, cloneState, destScope);
         }
-        else if (FFlag::LuauBetterScopeSelection && !FFlag::LuauBlockDiffFragmentSelection)
-        {
-            destScope->lvalueTypes[d] = builtins->unknownType;
-            Binding b;
-            b.typeId = builtins->unknownType;
-            destScope->bindings[Symbol(loc)] = b;
-        }
     }
 
     // Second - any referenced type alias bindings need to be placed in scope so type annotation can be resolved.
@@ -675,45 +212,7 @@ void cloneTypesFromFragment(
         }
     }
 
-    if (FFlag::LuauGlobalVariableModuleIsolation)
+    // Finally - clone the returnType on the staleScope. This helps avoid potential leaks of free types.
-    {
-        // Fourth  - prepopulate the global function types
-        for (const auto& name : f.globalFunctionsReferenced)
-        {
-            if (auto ty = staleModule->getModuleScope()->lookup(name))
-            {
-                destScope->bindings[name] = Binding{Luau::cloneIncremental(*ty, *destArena, cloneState, destScope)};
-            }
-            else
-            {
-                TypeId bt = destArena->addType(BlockedType{});
-                destScope->bindings[name] = Binding{bt};
-            }
-        }
-
-        // Fifth  - prepopulate the globals here
-        for (const auto& [name, def] : f.globalDefsToPrePopulate)
-        {
-            if (auto ty = staleModule->getModuleScope()->lookup(name))
-            {
-                destScope->lvalueTypes[def] = Luau::cloneIncremental(*ty, *destArena, cloneState, destScope);
-            }
-            else if (auto ty = destScope->lookup(name))
-            {
-                // This branch is a little strange - we are looking up a symbol in the destScope
-                // This scope has no parent pointer, and only cloned types are written to it, so this is a
-                // safe operation to do without cloning.
-                // The reason we do this, is the usage finder will traverse the global functions referenced first
-                // If there is no name associated with this function at the global scope, it must appear first in the fragment and we must
-                // create a blocked type for it. We write this blocked type directly into the `destScope` bindings
-                // Then when we go to traverse the `AstExprGlobal` associated with this function, we need to ensure that we map the def -> blockedType
-                // in `lvalueTypes`, which was previously written into `destScope`
-                destScope->lvalueTypes[def] = *ty;
-            }
-        }
-    }
-
-    // Finally, clone the returnType on the staleScope. This helps avoid potential leaks of free types.
     if (staleScope->returnType)
         destScope->returnType = Luau::cloneIncremental(staleScope->returnType, *destArena, cloneState, destScope);
 }
@@ -735,7 +234,7 @@ struct MixedModeIncrementalTCDefFinder : public AstVisitor
         // requires that we find the local/global `m` and place it in the environment.
         // The default behaviour here is to return false, and have individual visitors override
         // the specific behaviour they need.
-        return true;
+        return FFlag::LuauMixedModeDefFinderTraversesTypeOf;
     }
 
     bool visit(AstStatTypeAlias* alias) override
@@ -885,7 +384,7 @@ void cloneAndSquashScopes(
         }
     }
 
-    if (destScope->returnType)
+    if (FFlag::LuauCloneReturnTypePack && destScope->returnType)
         destScope->returnType = Luau::cloneIncremental(destScope->returnType, *destArena, cloneState, destScope);
 
     return;
@@ -901,10 +400,15 @@ static FrontendModuleResolver& getModuleResolver(Frontend& frontend, std::option
 
 bool statIsBeforePos(const AstNode* stat, const Position& cursorPos)
 {
+    if (FFlag::LuauIncrementalAutocompleteBugfixes)
+    {
         return (stat->location.begin < cursorPos);
+    }
+
+    return stat->location.begin < cursorPos && stat->location.begin.line < cursorPos.line;
 }
 
-FragmentAutocompleteAncestryResult findAncestryForFragmentParse_DEPRECATED(AstStatBlock* root, const Position& cursorPos)
+FragmentAutocompleteAncestryResult findAncestryForFragmentParse(AstStatBlock* root, const Position& cursorPos)
 {
     std::vector<AstNode*> ancestry = findAncestryAtPositionForAutocomplete(root, cursorPos);
     // Should always contain the root AstStat
@@ -933,7 +437,7 @@ FragmentAutocompleteAncestryResult findAncestryForFragmentParse_DEPRECATED(AstSt
         {
             for (auto stat : block->body)
             {
-                if (statIsBeforePos(stat, nearestStatement->location.begin))
+                if (statIsBeforePos(stat, FFlag::LuauIncrementalAutocompleteBugfixes ? nearestStatement->location.begin : cursorPos))
                 {
                     // This statement precedes the current one
                     if (auto statLoc = stat->as<AstStatLocal>())
@@ -982,6 +486,8 @@ FragmentAutocompleteAncestryResult findAncestryForFragmentParse_DEPRECATED(AstSt
                 }
             }
         }
+        if (FFlag::LuauIncrementalAutocompleteBugfixes)
+        {
             if (auto exprFunc = node->as<AstExprFunction>())
             {
                 if (exprFunc->location.contains(cursorPos))
@@ -994,6 +500,7 @@ FragmentAutocompleteAncestryResult findAncestryForFragmentParse_DEPRECATED(AstSt
                 }
             }
         }
+    }
 
     return {std::move(localMap), std::move(localStack), std::move(ancestry), std::move(nearestStatement)};
 }
@@ -1006,7 +513,7 @@ FragmentAutocompleteAncestryResult findAncestryForFragmentParse_DEPRECATED(AstSt
  * Example - your document is "foo bar baz" and getDocumentOffsets is passed (0, 4), (0, 8). This function returns the pair {3, 5}
  * which corresponds to the string " bar "
  */
-static std::pair<size_t, size_t> getDocumentOffsets(std::string_view src, const Position& startPos, const Position& endPos)
+std::pair<size_t, size_t> getDocumentOffsets(const std::string_view& src, const Position& startPos, const Position& endPos)
 {
     size_t lineCount = 0;
     size_t colCount = 0;
@@ -1063,14 +570,14 @@ static std::pair<size_t, size_t> getDocumentOffsets(std::string_view src, const
     return {min, len};
 }
 
-ScopePtr findClosestScope_DEPRECATED(const ModulePtr& module, const AstStat* nearestStatement)
+ScopePtr findClosestScope(const ModulePtr& module, const AstStat* nearestStatement)
 {
     LUAU_ASSERT(module->hasModuleScope());
 
     ScopePtr closest = module->getModuleScope();
 
     // find the scope the nearest statement belonged to.
-    for (const auto& [loc, sc] : module->scopes)
+    for (auto [loc, sc] : module->scopes)
     {
         if (loc.encloses(nearestStatement->location) && closest->location.begin <= loc.begin)
             closest = sc;
@@ -1079,38 +586,7 @@ ScopePtr findClosestScope_DEPRECATED(const ModulePtr& module, const AstStat* nea
     return closest;
 }
 
-ScopePtr findClosestScope(const ModulePtr& module, const Position& scopePos)
+std::optional<FragmentParseResult> parseFragment(
-{
-    LUAU_ASSERT(module->hasModuleScope());
-    if (FFlag::LuauBlockDiffFragmentSelection)
-    {
-        ScopePtr closest = module->getModuleScope();
-        // find the scope the nearest statement belonged to.
-        for (const auto& [loc, sc] : module->scopes)
-        {
-            // We bias towards the later scopes because those correspond to inner scopes.
-            // in the case of if statements, we create two scopes at the same location for the body of the then
-            // and else branches, so we need to bias later. This is why the closest update condition has a <=
-            // instead of a <
-            if (sc->location.contains(scopePos) && closest->location.begin <= sc->location.begin)
-                closest = sc;
-        }
-        return closest;
-    }
-    else
-    {
-        ScopePtr closest = module->getModuleScope();
-        // find the scope the nearest statement belonged to.
-        for (const auto& [loc, sc] : module->scopes)
-        {
-            if (sc->location.contains(scopePos) && closest->location.begin < sc->location.begin)
-                closest = sc;
-        }
-        return closest;
-    }
-}
-
-std::optional<FragmentParseResult> parseFragment_DEPRECATED(
     AstStatBlock* root,
     AstNameTable* names,
     std::string_view src,
@@ -1118,7 +594,7 @@ std::optional<FragmentParseResult> parseFragment_DEPRECATED(
     std::optional<Position> fragmentEndPosition
 )
 {
-    FragmentAutocompleteAncestryResult result = findAncestryForFragmentParse_DEPRECATED(root, cursorPos);
+    FragmentAutocompleteAncestryResult result = findAncestryForFragmentParse(root, cursorPos);
     AstStat* nearestStatement = result.nearestStatement;
 
     const Location& rootSpan = root->location;
@@ -1149,8 +625,8 @@ std::optional<FragmentParseResult> parseFragment_DEPRECATED(
     FragmentParseResult fragmentResult;
     fragmentResult.fragmentToParse = std::string(dbg.data(), parseLength);
     // For the duration of the incremental parse, we want to allow the name table to re-use duplicate names
-    if (FFlag::DebugLogFragmentsFromAutocomplete)
+    if (FFlag::LogFragmentsFromAutocomplete)
-        logLuau("Fragment Selected", dbg);
+        logLuau(dbg);
 
     ParseOptions opts;
     opts.allowDeclarationSyntax = false;
@@ -1225,6 +701,31 @@ ModulePtr cloneModule(CloneState& cloneState, const ModulePtr& source, std::uniq
     return incremental;
 }
 
+ModulePtr copyModule(const ModulePtr& result, std::unique_ptr<Allocator> alloc)
+{
+    ModulePtr incrementalModule = std::make_shared<Module>();
+    incrementalModule->name = result->name;
+    incrementalModule->humanReadableName = "Incremental$" + result->humanReadableName;
+    incrementalModule->internalTypes.owningModule = incrementalModule.get();
+    incrementalModule->interfaceTypes.owningModule = incrementalModule.get();
+    incrementalModule->allocator = std::move(alloc);
+    // Don't need to keep this alive (it's already on the source module)
+    copyModuleVec(incrementalModule->scopes, result->scopes);
+    copyModuleMap(incrementalModule->astTypes, result->astTypes);
+    copyModuleMap(incrementalModule->astTypePacks, result->astTypePacks);
+    copyModuleMap(incrementalModule->astExpectedTypes, result->astExpectedTypes);
+    // Don't need to clone astOriginalCallTypes
+    copyModuleMap(incrementalModule->astOverloadResolvedTypes, result->astOverloadResolvedTypes);
+    // Don't need to clone astForInNextTypes
+    copyModuleMap(incrementalModule->astForInNextTypes, result->astForInNextTypes);
+    // Don't need to clone astResolvedTypes
+    // Don't need to clone astResolvedTypePacks
+    // Don't need to clone upperBoundContributors
+    copyModuleMap(incrementalModule->astScopes, result->astScopes);
+    // Don't need to clone declared Globals;
+    return incrementalModule;
+}
+
 void mixedModeCompatibility(
     const ScopePtr& bottomScopeStale,
     const ScopePtr& myFakeScope,
@@ -1253,7 +754,7 @@ void mixedModeCompatibility(
 
 static void reportWaypoint(IFragmentAutocompleteReporter* reporter, FragmentAutocompleteWaypoint type)
 {
-    if (!reporter)
+    if (!FFlag::LuauFragmentAcSupportsReporter || !reporter)
         return;
 
     reporter->reportWaypoint(type);
@@ -1261,7 +762,7 @@ static void reportWaypoint(IFragmentAutocompleteReporter* reporter, FragmentAuto
 
 static void reportFragmentString(IFragmentAutocompleteReporter* reporter, std::string_view fragment)
 {
-    if (!reporter)
+    if (!FFlag::LuauFragmentAcSupportsReporter || !reporter)
         return;
 
     reporter->reportFragmentString(fragment);
@@ -1288,8 +789,10 @@ FragmentTypeCheckResult typecheckFragmentHelper_DEPRECATED(
     ModulePtr incrementalModule = nullptr;
     if (FFlag::LuauAllFreeTypesHaveScopes)
         incrementalModule = cloneModule(cloneState, stale, std::move(astAllocator), freshChildOfNearestScope.get());
-    else
+    else if (FFlag::LuauCloneIncrementalModule)
         incrementalModule = cloneModule_DEPRECATED(cloneState, stale, std::move(astAllocator));
+    else
+        incrementalModule = copyModule(stale, std::move(astAllocator));
 
     reportWaypoint(reporter, FragmentAutocompleteWaypoint::CloneModuleEnd);
     incrementalModule->checkedInNewSolver = true;
@@ -1343,6 +846,8 @@ FragmentTypeCheckResult typecheckFragmentHelper_DEPRECATED(
     };
 
     reportWaypoint(reporter, FragmentAutocompleteWaypoint::CloneAndSquashScopeStart);
+    if (FFlag::LuauCloneIncrementalModule)
+    {
         incrementalModule->scopes.emplace_back(root->location, freshChildOfNearestScope);
         cg.rootScope = freshChildOfNearestScope.get();
 
@@ -1363,7 +868,22 @@ FragmentTypeCheckResult typecheckFragmentHelper_DEPRECATED(
             for (auto p : cg.scopes)
                 incrementalModule->scopes.emplace_back(std::move(p));
         }
-
+    }
+    else
+    {
+        // Any additions to the scope must occur in a fresh scope
+        cg.rootScope = stale->getModuleScope().get();
+        incrementalModule->scopes.emplace_back(root->location, freshChildOfNearestScope);
+        mixedModeCompatibility(closestScope, freshChildOfNearestScope, stale, NotNull{&dfg}, root);
+        // closest Scope -> children = { ...., freshChildOfNearestScope}
+        // We need to trim nearestChild from the scope hierarchy
+        closestScope->children.emplace_back(freshChildOfNearestScope.get());
+        cg.visitFragmentRoot(freshChildOfNearestScope, root);
+        // Trim nearestChild from the closestScope
+        Scope* back = closestScope->children.back().get();
+        LUAU_ASSERT(back == freshChildOfNearestScope.get());
+        closestScope->children.pop_back();
+    }
     reportWaypoint(reporter, FragmentAutocompleteWaypoint::ConstraintSolverStart);
 
     if (FFlag::LuauAllFreeTypesHaveScopes)
@@ -1372,8 +892,6 @@ FragmentTypeCheckResult typecheckFragmentHelper_DEPRECATED(
         {
             if (!sc->interiorFreeTypes.has_value())
                 sc->interiorFreeTypes.emplace();
-            if (!sc->interiorFreeTypePacks.has_value())
-                sc->interiorFreeTypePacks.emplace();
         }
     }
 
@@ -1473,7 +991,7 @@ FragmentTypeCheckResult typecheckFragment_(
     SimplifierPtr simplifier = newSimplifier(NotNull{&incrementalModule->internalTypes}, frontend.builtinTypes);
 
     FrontendModuleResolver& resolver = getModuleResolver(frontend, opts);
-    std::shared_ptr<Scope> freshChildOfNearestScope = std::make_shared<Scope>(nullptr);
+
     /// Contraint Generator
     ConstraintGenerator cg{
         incrementalModule,
@@ -1483,7 +1001,7 @@ FragmentTypeCheckResult typecheckFragment_(
         NotNull{&resolver},
         frontend.builtinTypes,
         iceHandler,
-        FFlag::LuauGlobalVariableModuleIsolation ? freshChildOfNearestScope : stale->getModuleScope(),
+        stale->getModuleScope(),
         frontend.globals.globalTypeFunctionScope,
         nullptr,
         nullptr,
@@ -1492,9 +1010,9 @@ FragmentTypeCheckResult typecheckFragment_(
     };
 
     CloneState cloneState{frontend.builtinTypes};
+    std::shared_ptr<Scope> freshChildOfNearestScope = std::make_shared<Scope>(nullptr);
     incrementalModule->scopes.emplace_back(root->location, freshChildOfNearestScope);
     freshChildOfNearestScope->interiorFreeTypes.emplace();
-    freshChildOfNearestScope->interiorFreeTypePacks.emplace();
     cg.rootScope = freshChildOfNearestScope.get();
 
     if (FFlag::LuauUserTypeFunTypecheck)
@@ -1507,14 +1025,7 @@ FragmentTypeCheckResult typecheckFragment_(
 
     reportWaypoint(reporter, FragmentAutocompleteWaypoint::CloneAndSquashScopeStart);
     cloneTypesFromFragment(
-        cloneState,
+        cloneState, closestScope.get(), stale, NotNull{&incrementalModule->internalTypes}, NotNull{&dfg}, root, freshChildOfNearestScope.get()
-        closestScope.get(),
-        stale,
-        NotNull{&incrementalModule->internalTypes},
-        NotNull{&dfg},
-        frontend.builtinTypes,
-        root,
-        freshChildOfNearestScope.get()
     );
     reportWaypoint(reporter, FragmentAutocompleteWaypoint::CloneAndSquashScopeEnd);
 
@@ -1575,7 +1086,6 @@ std::pair<FragmentTypeCheckStatus, FragmentTypeCheckResult> typecheckFragment(
     std::optional<FrontendOptions> opts,
     std::string_view src,
     std::optional<Position> fragmentEndPosition,
-    AstStatBlock* recentParse,
     IFragmentAutocompleteReporter* reporter
 )
 {
@@ -1594,9 +1104,30 @@ std::pair<FragmentTypeCheckStatus, FragmentTypeCheckResult> typecheckFragment(
     }
 
     std::optional<FragmentParseResult> tryParse;
-    tryParse = FFlag::LuauBetterScopeSelection ? parseFragment(module->root, recentParse, module->names.get(), src, cursorPos, fragmentEndPosition)
+    if (FFlag::LuauModuleHoldsAstRoot)
-                                               : parseFragment_DEPRECATED(module->root, module->names.get(), src, cursorPos, fragmentEndPosition);
+    {
+        tryParse = parseFragment(module->root, module->names.get(), src, cursorPos, fragmentEndPosition);
+    }
+    else
+    {
+        const SourceModule* sourceModule = frontend.getSourceModule(moduleName);
+        if (!sourceModule)
+        {
+            LUAU_ASSERT(!"Expected Source Module for fragment typecheck");
+            return {};
+        }
 
+        if (FFlag::LuauIncrementalAutocompleteBugfixes)
+        {
+            if (sourceModule->allocator.get() != module->allocator.get())
+            {
+                return {FragmentTypeCheckStatus::SkipAutocomplete, {}};
+            }
+        }
+
+        tryParse = parseFragment(sourceModule->root, sourceModule->names.get(), src, cursorPos, fragmentEndPosition);
+        reportWaypoint(reporter, FragmentAutocompleteWaypoint::ParseFragmentEnd);
+    }
 
     if (!tryParse)
         return {FragmentTypeCheckStatus::SkipAutocomplete, {}};
@@ -1607,8 +1138,7 @@ std::pair<FragmentTypeCheckStatus, FragmentTypeCheckResult> typecheckFragment(
         return {FragmentTypeCheckStatus::SkipAutocomplete, {}};
 
     FrontendOptions frontendOptions = opts.value_or(frontend.options);
-    const ScopePtr& closestScope = FFlag::LuauBetterScopeSelection ? findClosestScope(module, parseResult.scopePos)
+    const ScopePtr& closestScope = findClosestScope(module, parseResult.nearestStatement);
-                                                                   : findClosestScope_DEPRECATED(module, parseResult.nearestStatement);
     FragmentTypeCheckResult result =
         FFlag::LuauIncrementalAutocompleteDemandBasedCloning
             ? typecheckFragment_(frontend, parseResult.root, module, closestScope, cursorPos, std::move(parseResult.alloc), frontendOptions, reporter)
@@ -1644,15 +1174,14 @@ FragmentAutocompleteStatusResult tryFragmentAutocomplete(
             context.opts,
             std::move(stringCompletionCB),
             context.DEPRECATED_fragmentEndPosition,
-            context.freshParse.root,
+            FFlag::LuauFragmentAcSupportsReporter ? context.reporter : nullptr
-            context.reporter
         );
         return {FragmentAutocompleteStatus::Success, std::move(fragmentAutocomplete)};
     }
     catch (const Luau::InternalCompilerError& e)
     {
-        if (FFlag::DebugLogFragmentsFromAutocomplete)
+        if (FFlag::LogFragmentsFromAutocomplete)
-            logLuau("tryFragmentAutocomplete exception", e.what());
+            logLuau(e.what());
         return {FragmentAutocompleteStatus::InternalIce, std::nullopt};
     }
 }
@@ -1665,28 +1194,40 @@ FragmentAutocompleteResult fragmentAutocomplete(
     std::optional<FrontendOptions> opts,
     StringCompletionCallback callback,
     std::optional<Position> fragmentEndPosition,
-    AstStatBlock* recentParse,
     IFragmentAutocompleteReporter* reporter
 )
 {
+    LUAU_ASSERT(FFlag::LuauAutocompleteRefactorsForIncrementalAutocomplete);
     LUAU_TIMETRACE_SCOPE("Luau::fragmentAutocomplete", "FragmentAutocomplete");
     LUAU_TIMETRACE_ARGUMENT("name", moduleName.c_str());
 
-    auto [tcStatus, tcResult] = typecheckFragment(frontend, moduleName, cursorPosition, opts, src, fragmentEndPosition, recentParse, reporter);
+    if (!FFlag::LuauModuleHoldsAstRoot)
+    {
+        const SourceModule* sourceModule = frontend.getSourceModule(moduleName);
+        if (!sourceModule)
+        {
+            LUAU_ASSERT(!"Expected Source Module for fragment typecheck");
+            return {};
+        }
+
+        // If the cursor is within a comment in the stale source module we should avoid providing a recommendation
+        if (isWithinComment(*sourceModule, fragmentEndPosition.value_or(cursorPosition)))
+            return {};
+    }
+
+    auto [tcStatus, tcResult] = typecheckFragment(frontend, moduleName, cursorPosition, opts, src, fragmentEndPosition, reporter);
     if (tcStatus == FragmentTypeCheckStatus::SkipAutocomplete)
         return {};
 
     reportWaypoint(reporter, FragmentAutocompleteWaypoint::TypecheckFragmentEnd);
     auto globalScope = (opts && opts->forAutocomplete) ? frontend.globalsForAutocomplete.globalScope.get() : frontend.globals.globalScope.get();
-    if (FFlag::DebugLogFragmentsFromAutocomplete)
+    if (FFlag::LogFragmentsFromAutocomplete)
-        logLuau("Fragment Autocomplete Source Script", src);
+        logLuau(src);
-    TypeArena arenaForAutocomplete_DEPRECATED;
+    TypeArena arenaForFragmentAutocomplete;
-    if (FFlag::LuauFragmentAcMemoryLeak)
-        unfreeze(tcResult.incrementalModule->internalTypes);
     auto result = Luau::autocomplete_(
         tcResult.incrementalModule,
         frontend.builtinTypes,
-        FFlag::LuauFragmentAcMemoryLeak ? &tcResult.incrementalModule->internalTypes : &arenaForAutocomplete_DEPRECATED,
+        &arenaForFragmentAutocomplete,
         tcResult.ancestry,
         globalScope,
         tcResult.freshScope,
@@ -1694,10 +1235,9 @@ FragmentAutocompleteResult fragmentAutocomplete(
         frontend.fileResolver,
         callback
     );
-    if (FFlag::LuauFragmentAcMemoryLeak)
+
-        freeze(tcResult.incrementalModule->internalTypes);
     reportWaypoint(reporter, FragmentAutocompleteWaypoint::AutocompleteEnd);
-    return {std::move(tcResult.incrementalModule), tcResult.freshScope.get(), std::move(arenaForAutocomplete_DEPRECATED), std::move(result)};
+    return {std::move(tcResult.incrementalModule), tcResult.freshScope.get(), std::move(arenaForFragmentAutocomplete), std::move(result)};
 }
 
 } // namespace Luau

Analysis/src/Frontend.cpp

@@ -1,6 +1,7 @@
 // This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
 #include "Luau/Frontend.h"
 
+#include "Luau/AnyTypeSummary.h"
 #include "Luau/BuiltinDefinitions.h"
 #include "Luau/Clone.h"
 #include "Luau/Common.h"
@@ -39,15 +40,20 @@ LUAU_FASTINT(LuauTarjanChildLimit)
 LUAU_FASTFLAG(LuauInferInNoCheckMode)
 LUAU_FASTFLAGVARIABLE(LuauKnowsTheDataModel3)
 LUAU_FASTFLAG(LuauSolverV2)
-LUAU_DYNAMIC_FASTFLAGVARIABLE(LuauRethrowKnownExceptions, false)
-LUAU_FASTFLAG(DebugLuauGreedyGeneralization)
 LUAU_FASTFLAGVARIABLE(DebugLuauLogSolverToJson)
 LUAU_FASTFLAGVARIABLE(DebugLuauLogSolverToJsonFile)
 LUAU_FASTFLAGVARIABLE(DebugLuauForbidInternalTypes)
 LUAU_FASTFLAGVARIABLE(DebugLuauForceStrictMode)
 LUAU_FASTFLAGVARIABLE(DebugLuauForceNonStrictMode)
+LUAU_DYNAMIC_FASTFLAGVARIABLE(LuauRunCustomModuleChecks, false)
 
-LUAU_FASTFLAG(LuauTypeFunResultInAutocomplete)
+LUAU_FASTFLAGVARIABLE(LuauModuleHoldsAstRoot)
+
+LUAU_FASTFLAGVARIABLE(LuauFixMultithreadTypecheck)
+
+LUAU_FASTFLAG(StudioReportLuauAny2)
+
+LUAU_FASTFLAGVARIABLE(LuauSelectivelyRetainDFGArena)
 
 namespace Luau
 {
@@ -129,9 +135,9 @@ static void generateDocumentationSymbols(TypeId ty, const std::string& rootName)
             prop.documentationSymbol = rootName + "." + name;
         }
     }
-    else if (ExternType* etv = getMutable<ExternType>(ty))
+    else if (ClassType* ctv = getMutable<ClassType>(ty))
     {
-        for (auto& [name, prop] : etv->props)
+        for (auto& [name, prop] : ctv->props)
         {
             prop.documentationSymbol = rootName + "." + name;
         }
@@ -455,6 +461,20 @@ CheckResult Frontend::check(const ModuleName& name, std::optional<FrontendOption
 
         if (item.name == name)
             checkResult.lintResult = item.module->lintResult;
+
+        if (FFlag::StudioReportLuauAny2 && item.options.retainFullTypeGraphs)
+        {
+            if (item.module)
+            {
+                const SourceModule& sourceModule = *item.sourceModule;
+                if (sourceModule.mode == Luau::Mode::Strict)
+                {
+                    item.module->ats.root = toString(sourceModule.root);
+                }
+                item.module->ats.rootSrc = sourceModule.root;
+                item.module->ats.traverse(item.module.get(), sourceModule.root, NotNull{&builtinTypes_});
+            }
+        }
     }
 
     return checkResult;
@@ -476,6 +496,11 @@ std::vector<ModuleName> Frontend::checkQueuedModules(
     std::function<bool(size_t done, size_t total)> progress
 )
 {
+    if (!FFlag::LuauFixMultithreadTypecheck)
+    {
+        return checkQueuedModules_DEPRECATED(optionOverride, executeTask, progress);
+    }
+
     FrontendOptions frontendOptions = optionOverride.value_or(options);
     if (FFlag::LuauSolverV2)
         frontendOptions.forAutocomplete = false;
@@ -660,6 +685,247 @@ std::vector<ModuleName> Frontend::checkQueuedModules(
     return checkedModules;
 }
 
+std::vector<ModuleName> Frontend::checkQueuedModules_DEPRECATED(
+    std::optional<FrontendOptions> optionOverride,
+    std::function<void(std::function<void()> task)> executeTask,
+    std::function<bool(size_t done, size_t total)> progress
+)
+{
+    LUAU_ASSERT(!FFlag::LuauFixMultithreadTypecheck);
+
+    FrontendOptions frontendOptions = optionOverride.value_or(options);
+    if (FFlag::LuauSolverV2)
+        frontendOptions.forAutocomplete = false;
+
+    // By taking data into locals, we make sure queue is cleared at the end, even if an ICE or a different exception is thrown
+    std::vector<ModuleName> currModuleQueue;
+    std::swap(currModuleQueue, moduleQueue);
+
+    DenseHashSet<Luau::ModuleName> seen{{}};
+    std::vector<BuildQueueItem> buildQueueItems;
+
+    for (const ModuleName& name : currModuleQueue)
+    {
+        if (seen.contains(name))
+            continue;
+
+        if (!isDirty(name, frontendOptions.forAutocomplete))
+        {
+            seen.insert(name);
+            continue;
+        }
+
+        std::vector<ModuleName> queue;
+        bool cycleDetected = parseGraph(
+            queue,
+            name,
+            frontendOptions.forAutocomplete,
+            [&seen](const ModuleName& name)
+            {
+                return seen.contains(name);
+            }
+        );
+
+        addBuildQueueItems(buildQueueItems, queue, cycleDetected, seen, frontendOptions);
+    }
+
+    if (buildQueueItems.empty())
+        return {};
+
+    // We need a mapping from modules to build queue slots
+    std::unordered_map<ModuleName, size_t> moduleNameToQueue;
+
+    for (size_t i = 0; i < buildQueueItems.size(); i++)
+    {
+        BuildQueueItem& item = buildQueueItems[i];
+        moduleNameToQueue[item.name] = i;
+    }
+
+    // Default task execution is single-threaded and immediate
+    if (!executeTask)
+    {
+        executeTask = [](std::function<void()> task)
+        {
+            task();
+        };
+    }
+
+    std::mutex mtx;
+    std::condition_variable cv;
+    std::vector<size_t> readyQueueItems;
+
+    size_t processing = 0;
+    size_t remaining = buildQueueItems.size();
+
+    auto itemTask = [&](size_t i)
+    {
+        BuildQueueItem& item = buildQueueItems[i];
+
+        try
+        {
+            checkBuildQueueItem(item);
+        }
+        catch (...)
+        {
+            item.exception = std::current_exception();
+        }
+
+        {
+            std::unique_lock guard(mtx);
+            readyQueueItems.push_back(i);
+        }
+
+        cv.notify_one();
+    };
+
+    auto sendItemTask = [&](size_t i)
+    {
+        BuildQueueItem& item = buildQueueItems[i];
+
+        item.processing = true;
+        processing++;
+
+        executeTask(
+            [&itemTask, i]()
+            {
+                itemTask(i);
+            }
+        );
+    };
+
+    auto sendCycleItemTask = [&]
+    {
+        for (size_t i = 0; i < buildQueueItems.size(); i++)
+        {
+            BuildQueueItem& item = buildQueueItems[i];
+
+            if (!item.processing)
+            {
+                sendItemTask(i);
+                break;
+            }
+        }
+    };
+
+    // In a first pass, check modules that have no dependencies and record info of those modules that wait
+    for (size_t i = 0; i < buildQueueItems.size(); i++)
+    {
+        BuildQueueItem& item = buildQueueItems[i];
+
+        for (const ModuleName& dep : item.sourceNode->requireSet)
+        {
+            if (auto it = sourceNodes.find(dep); it != sourceNodes.end())
+            {
+                if (it->second->hasDirtyModule(frontendOptions.forAutocomplete))
+                {
+                    item.dirtyDependencies++;
+
+                    buildQueueItems[moduleNameToQueue[dep]].reverseDeps.push_back(i);
+                }
+            }
+        }
+
+        if (item.dirtyDependencies == 0)
+            sendItemTask(i);
+    }
+
+    // Not a single item was found, a cycle in the graph was hit
+    if (processing == 0)
+        sendCycleItemTask();
+
+    std::vector<size_t> nextItems;
+    std::optional<size_t> itemWithException;
+    bool cancelled = false;
+
+    while (remaining != 0)
+    {
+        {
+            std::unique_lock guard(mtx);
+
+            // If nothing is ready yet, wait
+            cv.wait(
+                guard,
+                [&readyQueueItems]
+                {
+                    return !readyQueueItems.empty();
+                }
+            );
+
+            // Handle checked items
+            for (size_t i : readyQueueItems)
+            {
+                const BuildQueueItem& item = buildQueueItems[i];
+
+                // If exception was thrown, stop adding new items and wait for processing items to complete
+                if (item.exception)
+                    itemWithException = i;
+
+                if (item.module && item.module->cancelled)
+                    cancelled = true;
+
+                if (itemWithException || cancelled)
+                    break;
+
+                recordItemResult(item);
+
+                // Notify items that were waiting for this dependency
+                for (size_t reverseDep : item.reverseDeps)
+                {
+                    BuildQueueItem& reverseDepItem = buildQueueItems[reverseDep];
+
+                    LUAU_ASSERT(reverseDepItem.dirtyDependencies != 0);
+                    reverseDepItem.dirtyDependencies--;
+
+                    // In case of a module cycle earlier, check if unlocked an item that was already processed
+                    if (!reverseDepItem.processing && reverseDepItem.dirtyDependencies == 0)
+                        nextItems.push_back(reverseDep);
+                }
+            }
+
+            LUAU_ASSERT(processing >= readyQueueItems.size());
+            processing -= readyQueueItems.size();
+
+            LUAU_ASSERT(remaining >= readyQueueItems.size());
+            remaining -= readyQueueItems.size();
+            readyQueueItems.clear();
+        }
+
+        if (progress)
+        {
+            if (!progress(buildQueueItems.size() - remaining, buildQueueItems.size()))
+                cancelled = true;
+        }
+
+        // Items cannot be submitted while holding the lock
+        for (size_t i : nextItems)
+            sendItemTask(i);
+        nextItems.clear();
+
+        if (processing == 0)
+        {
+            // Typechecking might have been cancelled by user, don't return partial results
+            if (cancelled)
+                return {};
+
+            // We might have stopped because of a pending exception
+            if (itemWithException)
+                recordItemResult(buildQueueItems[*itemWithException]);
+        }
+
+        // If we aren't done, but don't have anything processing, we hit a cycle
+        if (remaining != 0 && processing == 0)
+            sendCycleItemTask();
+    }
+
+    std::vector<ModuleName> checkedModules;
+    checkedModules.reserve(buildQueueItems.size());
+
+    for (size_t i = 0; i < buildQueueItems.size(); i++)
+        checkedModules.push_back(std::move(buildQueueItems[i].name));
+
+    return checkedModules;
+}
+
 std::optional<CheckResult> Frontend::getCheckResult(const ModuleName& name, bool accumulateNested, bool forAutocomplete)
 {
     if (FFlag::LuauSolverV2)
@@ -951,7 +1217,7 @@ void Frontend::checkBuildQueueItem(BuildQueueItem& item)
         item.stats.timeCheck += duration;
         item.stats.filesStrict += 1;
 
-        if (item.options.customModuleCheck)
+        if (DFFlag::LuauRunCustomModuleChecks && item.options.customModuleCheck)
             item.options.customModuleCheck(sourceModule, *moduleForAutocomplete);
 
         item.module = moduleForAutocomplete;
@@ -971,7 +1237,7 @@ void Frontend::checkBuildQueueItem(BuildQueueItem& item)
     item.stats.filesStrict += mode == Mode::Strict;
     item.stats.filesNonstrict += mode == Mode::Nonstrict;
 
-    if (item.options.customModuleCheck)
+    if (DFFlag::LuauRunCustomModuleChecks && item.options.customModuleCheck)
         item.options.customModuleCheck(sourceModule, *module);
 
     if (FFlag::LuauSolverV2 && mode == Mode::NoCheck)
@@ -1003,8 +1269,11 @@ void Frontend::checkBuildQueueItem(BuildQueueItem& item)
         freeze(module->interfaceTypes);
 
         module->internalTypes.clear();
+        if (FFlag::LuauSelectivelyRetainDFGArena)
+        {
             module->defArena.allocator.clear();
             module->keyArena.allocator.clear();
+        }
 
         module->astTypes.clear();
         module->astTypePacks.clear();
@@ -1098,19 +1367,6 @@ void Frontend::performQueueItemTask(std::shared_ptr<BuildQueueWorkState> state,
 {
     BuildQueueItem& item = state->buildQueueItems[itemPos];
 
-    if (DFFlag::LuauRethrowKnownExceptions)
-    {
-        try
-        {
-            checkBuildQueueItem(item);
-        }
-        catch (const Luau::InternalCompilerError&)
-        {
-            item.exception = std::current_exception();
-        }
-    }
-    else
-    {
     try
     {
         checkBuildQueueItem(item);
@@ -1119,7 +1375,6 @@ void Frontend::performQueueItemTask(std::shared_ptr<BuildQueueWorkState> state,
     {
         item.exception = std::current_exception();
     }
-    }
 
     {
         std::unique_lock guard(state->mtx);
@@ -1305,7 +1560,7 @@ ModulePtr check(
 
 struct InternalTypeFinder : TypeOnceVisitor
 {
-    bool visit(TypeId, const ExternType&) override
+    bool visit(TypeId, const ClassType&) override
     {
         return false;
     }
@@ -1377,6 +1632,7 @@ ModulePtr check(
     result->interfaceTypes.owningModule = result.get();
     result->allocator = sourceModule.allocator;
     result->names = sourceModule.names;
+    if (FFlag::LuauModuleHoldsAstRoot)
         result->root = sourceModule.root;
 
     iceHandler->moduleName = sourceModule.name;
@@ -1402,7 +1658,7 @@ ModulePtr check(
     SimplifierPtr simplifier = newSimplifier(NotNull{&result->internalTypes}, builtinTypes);
     TypeFunctionRuntime typeFunctionRuntime{iceHandler, NotNull{&limits}};
 
-    typeFunctionRuntime.allowEvaluation = FFlag::LuauTypeFunResultInAutocomplete || sourceModule.parseErrors.empty();
+    typeFunctionRuntime.allowEvaluation = sourceModule.parseErrors.empty();
 
     ConstraintGenerator cg{
         result,
@@ -1420,36 +1676,10 @@ ModulePtr check(
         requireCycles
     };
 
-    // FIXME: Delete this flag when clipping FFlag::DebugLuauGreedyGeneralization.
-    //
-    // This optional<> only exists so that we can run one constructor when the flag
-    // is set, and another when it is unset.
-    std::optional<ConstraintSolver> cs;
-
-    if (FFlag::DebugLuauGreedyGeneralization)
-    {
-        ConstraintSet constraintSet = cg.run(sourceModule.root);
-        result->errors = std::move(constraintSet.errors);
-
-        cs.emplace(
-            NotNull{&normalizer},
-            NotNull{simplifier.get()},
-            NotNull{&typeFunctionRuntime},
-            result->name,
-            moduleResolver,
-            requireCycles,
-            logger.get(),
-            NotNull{&dfg},
-            limits,
-            std::move(constraintSet)
-        );
-    }
-    else
-    {
     cg.visitModuleRoot(sourceModule.root);
     result->errors = std::move(cg.errors);
 
-        cs.emplace(
+    ConstraintSolver cs{
         NotNull{&normalizer},
         NotNull{simplifier.get()},
         NotNull{&typeFunctionRuntime},
@@ -1462,17 +1692,14 @@ ModulePtr check(
         logger.get(),
         NotNull{&dfg},
         limits
-        );
+    };
-    }
-
-    LUAU_ASSERT(bool(cs));
 
     if (options.randomizeConstraintResolutionSeed)
-        cs->randomize(*options.randomizeConstraintResolutionSeed);
+        cs.randomize(*options.randomizeConstraintResolutionSeed);
 
     try
     {
-        cs->run();
+        cs.run();
     }
     catch (const TimeLimitError&)
     {
@@ -1492,12 +1719,12 @@ ModulePtr check(
             printf("%s\n", output.c_str());
     }
 
-    for (TypeError& e : cs->errors)
+    for (TypeError& e : cs.errors)
         result->errors.emplace_back(std::move(e));
 
     result->scopes = std::move(cg.scopes);
     result->type = sourceModule.type;
-    result->upperBoundContributors = std::move(cs->upperBoundContributors);
+    result->upperBoundContributors = std::move(cs.upperBoundContributors);
 
     if (result->timeout || result->cancelled)
     {

Analysis/src/Generalization.cpp

@@ -4,85 +4,19 @@
 
 #include "Luau/Common.h"
 #include "Luau/DenseHash.h"
-#include "Luau/InsertionOrderedMap.h"
-#include "Luau/Polarity.h"
 #include "Luau/Scope.h"
-#include "Luau/ToString.h"
 #include "Luau/Type.h"
+#include "Luau/ToString.h"
 #include "Luau/TypeArena.h"
 #include "Luau/TypePack.h"
-#include "Luau/Substitution.h"
 #include "Luau/VisitType.h"
 
-LUAU_FASTFLAG(DebugLuauGreedyGeneralization)
+LUAU_FASTFLAG(LuauAutocompleteRefactorsForIncrementalAutocomplete)
-
+LUAU_FASTFLAGVARIABLE(LuauGeneralizationRemoveRecursiveUpperBound2)
-LUAU_FASTFLAGVARIABLE(LuauNonReentrantGeneralization2)
 
 namespace Luau
 {
 
-namespace
-{
-
-template<typename T>
-struct OrderedSet
-{
-    using iterator = typename std::vector<T>::iterator;
-    using const_iterator = typename std::vector<T>::const_iterator;
-
-    bool empty() const
-    {
-        return elements.empty();
-    }
-
-    size_t size() const
-    {
-        return elements.size();
-    }
-
-    void insert(T t)
-    {
-        if (!elementSet.contains(t))
-        {
-            elementSet.insert(t);
-            elements.push_back(t);
-        }
-    }
-
-    iterator begin()
-    {
-        return elements.begin();
-    }
-
-    const_iterator begin() const
-    {
-        return elements.begin();
-    }
-
-    iterator end()
-    {
-        return elements.end();
-    }
-
-    const_iterator end() const
-    {
-        return elements.end();
-    }
-
-    /// Move the underlying vector out of the OrderedSet.
-    std::vector<T> takeVector()
-    {
-        elementSet.clear();
-        return std::move(elements);
-    }
-
-private:
-    std::vector<T> elements;
-    DenseHashSet<T> elementSet{nullptr};
-};
-
-} // namespace
-
 struct MutatingGeneralizer : TypeOnceVisitor
 {
     NotNull<TypeArena> arena;
@@ -96,6 +30,7 @@ struct MutatingGeneralizer : TypeOnceVisitor
     std::vector<TypePackId> genericPacks;
 
     bool isWithinFunction = false;
+    bool avoidSealingTables = false;
 
     MutatingGeneralizer(
         NotNull<TypeArena> arena,
@@ -103,7 +38,8 @@ struct MutatingGeneralizer : TypeOnceVisitor
         NotNull<Scope> scope,
         NotNull<DenseHashSet<TypeId>> cachedTypes,
         DenseHashMap<const void*, size_t> positiveTypes,
-        DenseHashMap<const void*, size_t> negativeTypes
+        DenseHashMap<const void*, size_t> negativeTypes,
+        bool avoidSealingTables
     )
         : TypeOnceVisitor(/* skipBoundTypes */ true)
         , arena(arena)
@@ -112,6 +48,7 @@ struct MutatingGeneralizer : TypeOnceVisitor
         , cachedTypes(cachedTypes)
         , positiveTypes(std::move(positiveTypes))
         , negativeTypes(std::move(negativeTypes))
+        , avoidSealingTables(avoidSealingTables)
     {
     }
 
@@ -162,7 +99,7 @@ struct MutatingGeneralizer : TypeOnceVisitor
                 LUAU_ASSERT(onlyType != haystack);
                 emplaceType<BoundType>(asMutable(haystack), onlyType);
             }
-            else if (ut->options.empty())
+            else if (FFlag::LuauGeneralizationRemoveRecursiveUpperBound2 && ut->options.empty())
             {
                 emplaceType<BoundType>(asMutable(haystack), builtinTypes->neverType);
             }
@@ -209,7 +146,7 @@ struct MutatingGeneralizer : TypeOnceVisitor
                 LUAU_ASSERT(onlyType != needle);
                 emplaceType<BoundType>(asMutable(needle), onlyType);
             } 
-            else if (it->parts.empty())
+            else if (FFlag::LuauGeneralizationRemoveRecursiveUpperBound2 && it->parts.empty())
             {
                 emplaceType<BoundType>(asMutable(needle), builtinTypes->unknownType);
             }
@@ -337,15 +274,6 @@ struct MutatingGeneralizer : TypeOnceVisitor
             return 0;
     }
 
-    template<typename TID>
-    static size_t getCount(const DenseHashMap<TID, size_t>& map, TID ty)
-    {
-        if (const size_t* count = map.find(ty))
-            return *count;
-        else
-            return 0;
-    }
-
     bool visit(TypeId ty, const TableType&) override
     {
         if (cachedTypes->contains(ty))
@@ -364,6 +292,7 @@ struct MutatingGeneralizer : TypeOnceVisitor
         TableType* tt = getMutable<TableType>(ty);
         LUAU_ASSERT(tt);
 
+        if (!avoidSealingTables)
             tt->state = TableState::Sealed;
 
         return true;
@@ -403,12 +332,28 @@ struct FreeTypeSearcher : TypeVisitor
     {
     }
 
-    bool isWithinFunction = false;
+    enum Polarity
-    Polarity polarity = Polarity::Positive;
+    {
+        Positive,
+        Negative,
+        Both,
+    };
+
+    Polarity polarity = Positive;
 
     void flip()
     {
-        polarity = invert(polarity);
+        switch (polarity)
+        {
+        case Positive:
+            polarity = Negative;
+            break;
+        case Negative:
+            polarity = Positive;
+            break;
+        case Both:
+            break;
+        }
     }
 
     DenseHashSet<const void*> seenPositive{nullptr};
@@ -418,7 +363,7 @@ struct FreeTypeSearcher : TypeVisitor
     {
         switch (polarity)
         {
-        case Polarity::Positive:
+        case Positive:
         {
             if (seenPositive.contains(ty))
                 return true;
@@ -426,7 +371,7 @@ struct FreeTypeSearcher : TypeVisitor
             seenPositive.insert(ty);
             return false;
         }
-        case Polarity::Negative:
+        case Negative:
         {
             if (seenNegative.contains(ty))
                 return true;
@@ -434,7 +379,7 @@ struct FreeTypeSearcher : TypeVisitor
             seenNegative.insert(ty);
             return false;
         }
-        case Polarity::Mixed:
+        case Both:
         {
             if (seenPositive.contains(ty) && seenNegative.contains(ty))
                 return true;
@@ -443,21 +388,17 @@ struct FreeTypeSearcher : TypeVisitor
             seenNegative.insert(ty);
             return false;
         }
-        default:
-            LUAU_ASSERT(!"Unreachable");
         }
 
         return false;
     }
 
+    // The keys in these maps are either TypeIds or TypePackIds. It's safe to
+    // mix them because we only use these pointers as unique keys.  We never
+    // indirect them.
     DenseHashMap<const void*, size_t> negativeTypes{0};
     DenseHashMap<const void*, size_t> positiveTypes{0};
 
-    InsertionOrderedMap<TypeId, GeneralizationParams<TypeId>> types;
-    InsertionOrderedMap<TypePackId, GeneralizationParams<TypePackId>> typePacks;
-
-    OrderedSet<TypeId> unsealedTables;
-
     bool visit(TypeId ty) override
     {
         if (cachedTypes->contains(ty) || seenWithCurrentPolarity(ty))
@@ -468,24 +409,6 @@ struct FreeTypeSearcher : TypeVisitor
     }
 
     bool visit(TypeId ty, const FreeType& ft) override
-    {
-        if (FFlag::LuauNonReentrantGeneralization2)
-        {
-            if (!subsumes(scope, ft.scope))
-                return true;
-
-            GeneralizationParams<TypeId>& params = types[ty];
-            ++params.useCount;
-
-            if (cachedTypes->contains(ty) || seenWithCurrentPolarity(ty))
-                return false;
-
-            if (!isWithinFunction)
-                params.foundOutsideFunctions = true;
-
-            params.polarity |= polarity;
-        }
-        else
     {
         if (cachedTypes->contains(ty) || seenWithCurrentPolarity(ty))
             return false;
@@ -495,19 +418,16 @@ struct FreeTypeSearcher : TypeVisitor
 
         switch (polarity)
         {
-            case Polarity::Positive:
+        case Positive:
             positiveTypes[ty]++;
             break;
-            case Polarity::Negative:
+        case Negative:
             negativeTypes[ty]++;
             break;
-            case Polarity::Mixed:
+        case Both:
             positiveTypes[ty]++;
             negativeTypes[ty]++;
             break;
-            default:
-                LUAU_ASSERT(!"Unreachable");
-            }
         }
 
         return true;
@@ -519,26 +439,19 @@ struct FreeTypeSearcher : TypeVisitor
             return false;
 
         if ((tt.state == TableState::Free || tt.state == TableState::Unsealed) && subsumes(scope, tt.scope))
-        {
-            if (FFlag::LuauNonReentrantGeneralization2)
-                unsealedTables.insert(ty);
-            else
         {
             switch (polarity)
             {
-                case Polarity::Positive:
+            case Positive:
                 positiveTypes[ty]++;
                 break;
-                case Polarity::Negative:
+            case Negative:
                 negativeTypes[ty]++;
                 break;
-                case Polarity::Mixed:
+            case Both:
                 positiveTypes[ty]++;
                 negativeTypes[ty]++;
                 break;
-                default:
-                    LUAU_ASSERT(!"Unreachable");
-                }
             }
         }
 
@@ -548,10 +461,10 @@ struct FreeTypeSearcher : TypeVisitor
                 traverse(*prop.readTy);
             else
             {
-                LUAU_ASSERT(prop.isShared());
+                LUAU_ASSERT(prop.isShared() || FFlag::LuauAutocompleteRefactorsForIncrementalAutocomplete);
 
                 Polarity p = polarity;
-                polarity = Polarity::Mixed;
+                polarity = Both;
                 traverse(prop.type());
                 polarity = p;
             }
@@ -559,27 +472,8 @@ struct FreeTypeSearcher : TypeVisitor
 
         if (tt.indexer)
         {
-            if (FFlag::LuauNonReentrantGeneralization2)
-            {
-                // {[K]: V} is equivalent to three functions: get, set, and iterate
-                //
-                // (K) -> V
-                // (K, V) -> ()
-                // () -> {K}
-                //
-                // K and V therefore both have mixed polarity.
-
-                const Polarity p = polarity;
-                polarity = Polarity::Mixed;
             traverse(tt.indexer->indexType);
             traverse(tt.indexer->indexResultType);
-                polarity = p;
-            }
-            else
-            {
-                traverse(tt.indexer->indexType);
-                traverse(tt.indexer->indexResultType);
-            }
         }
 
         return false;
@@ -590,21 +484,16 @@ struct FreeTypeSearcher : TypeVisitor
         if (cachedTypes->contains(ty) || seenWithCurrentPolarity(ty))
             return false;
 
-        const bool oldValue = isWithinFunction;
-        isWithinFunction = true;
-
         flip();
         traverse(ft.argTypes);
         flip();
 
         traverse(ft.retTypes);
 
-        isWithinFunction = oldValue;
-
         return false;
     }
 
-    bool visit(TypeId, const ExternType&) override
+    bool visit(TypeId, const ClassType&) override
     {
         return false;
     }
@@ -617,33 +506,18 @@ struct FreeTypeSearcher : TypeVisitor
         if (!subsumes(scope, ftp.scope))
             return true;
 
-        if (FFlag::LuauNonReentrantGeneralization2)
-        {
-            GeneralizationParams<TypePackId>& params = typePacks[tp];
-            ++params.useCount;
-
-            if (!isWithinFunction)
-                params.foundOutsideFunctions = true;
-
-            params.polarity |= polarity;
-        }
-        else
-        {
         switch (polarity)
         {
-            case Polarity::Positive:
+        case Positive:
             positiveTypes[tp]++;
             break;
-            case Polarity::Negative:
+        case Negative:
             negativeTypes[tp]++;
             break;
-            case Polarity::Mixed:
+        case Both:
             positiveTypes[tp]++;
             negativeTypes[tp]++;
             break;
-            default:
-                LUAU_ASSERT(!"Unreachable");
-            }
         }
 
         return true;
@@ -896,7 +770,7 @@ struct TypeCacher : TypeOnceVisitor
         return false;
     }
 
-    bool visit(TypeId ty, const ExternType&) override
+    bool visit(TypeId ty, const ClassType&) override
     {
         cache(ty);
         return false;
@@ -1093,277 +967,13 @@ struct TypeCacher : TypeOnceVisitor
     }
 };
 
-struct RemoveType : Substitution // NOLINT
-{
-    NotNull<BuiltinTypes> builtinTypes;
-    TypeId needle;
-
-    RemoveType(NotNull<BuiltinTypes> builtinTypes, TypeArena* arena, TypeId needle)
-        : Substitution(arena)
-        , builtinTypes(builtinTypes)
-        , needle(needle)
-    {
-    }
-
-    bool ignoreChildren(TypeId ty) override
-    {
-        if (get<UnionType>(ty) || get<IntersectionType>(ty))
-            return false;
-        else
-            return true;
-    }
-
-    bool isDirty(TypeId ty) override
-    {
-        // A union or intersection is dirty if it contains the needle or if it has any duplicate members.
-        if (auto ut = get<UnionType>(ty))
-        {
-            DenseHashSet<TypeId> distinctParts{nullptr};
-            size_t count = 0;
-            for (TypeId part : ut)
-            {
-                ++count;
-                if (part == needle)
-                    return true;
-                distinctParts.insert(follow(part));
-            }
-            return distinctParts.size() != count;
-        }
-        else if (auto it = get<IntersectionType>(ty))
-        {
-            DenseHashSet<TypeId> distinctParts{nullptr};
-            size_t count = 0;
-            for (TypeId part : it)
-            {
-                ++count;
-                if (part == needle)
-                    return true;
-                distinctParts.insert(follow(part));
-            }
-            return distinctParts.size() != count;
-        }
-
-        return false;
-    }
-
-    bool isDirty(TypePackId tp) override
-    {
-        return false;
-    }
-
-    TypeId clean(TypeId ty) override
-    {
-        if (auto ut = get<UnionType>(ty))
-        {
-            OrderedSet<TypeId> newParts;
-
-            for (TypeId ty : ut)
-            {
-                if (ty != needle)
-                    newParts.insert(ty);
-            }
-
-            if (newParts.empty())
-                return builtinTypes->neverType;
-            else if (newParts.size() == 1)
-            {
-                TypeId onlyType = *newParts.begin();
-                LUAU_ASSERT(onlyType != needle);
-                return onlyType;
-            }
-            else
-                return arena->addType(UnionType{newParts.takeVector()});
-        }
-        else if (auto it = get<IntersectionType>(ty))
-        {
-            OrderedSet<TypeId> newParts;
-
-            for (TypeId ty : it)
-            {
-                if (ty != needle)
-                    newParts.insert(ty);
-            }
-
-            if (newParts.empty())
-                return builtinTypes->unknownType;
-            else if (newParts.size() == 1)
-            {
-                TypeId onlyType = *newParts.begin();
-                LUAU_ASSERT(onlyType != needle);
-                return onlyType;
-            }
-            else
-                return arena->addType(IntersectionType{newParts.takeVector()});
-        }
-        else
-            return ty;
-    }
-
-    TypePackId clean(TypePackId tp) override
-    {
-        return tp;
-    }
-};
-
-/**
- * Remove occurrences of `needle` within `haystack`.  This is used to cull cyclic bounds from free types.
- *
- * @param haystack Either the upper or lower bound of a free type.
- * @param needle The type to be removed.
- */
-[[nodiscard]]
-static std::optional<
-    TypeId> removeType(NotNull<TypeArena> arena, NotNull<BuiltinTypes> builtinTypes, TypeId haystack, TypeId needle)
-{
-    RemoveType rt{builtinTypes, arena, needle};
-    return rt.substitute(haystack);
-}
-
-GeneralizationResult<TypeId> generalizeType(
-    NotNull<TypeArena> arena,
-    NotNull<BuiltinTypes> builtinTypes,
-    NotNull<Scope> scope,
-    TypeId freeTy,
-    const GeneralizationParams<TypeId>& params
-)
-{
-    freeTy = follow(freeTy);
-
-    FreeType* ft = getMutable<FreeType>(freeTy);
-    LUAU_ASSERT(ft);
-
-    LUAU_ASSERT(isKnown(params.polarity));
-
-    const bool hasLowerBound = !get<NeverType>(follow(ft->lowerBound));
-    const bool hasUpperBound = !get<UnknownType>(follow(ft->upperBound));
-
-    const bool isWithinFunction = !params.foundOutsideFunctions;
-
-    if (!hasLowerBound && !hasUpperBound)
-    {
-        if (!isWithinFunction || (!FFlag::DebugLuauGreedyGeneralization && (params.polarity != Polarity::Mixed && params.useCount == 1)))
-            emplaceType<BoundType>(asMutable(freeTy), builtinTypes->unknownType);
-        else
-        {
-            emplaceType<GenericType>(asMutable(freeTy), scope, params.polarity);
-            return {freeTy, /*wasReplacedByGeneric*/ true};
-        }
-    }
-    // It is possible that this free type has other free types in its upper
-    // or lower bounds.  If this is the case, we must replace those
-    // references with never (for the lower bound) or unknown (for the upper
-    // bound).
-    //
-    // If we do not do this, we get tautological bounds like a <: a <: unknown.
-    else if (isPositive(params.polarity) && !hasUpperBound)
-    {
-        TypeId lb = follow(ft->lowerBound);
-        if (FreeType* lowerFree = getMutable<FreeType>(lb); lowerFree && lowerFree->upperBound == freeTy)
-            lowerFree->upperBound = builtinTypes->unknownType;
-        else
-        {
-            std::optional<TypeId> removed = removeType(arena, builtinTypes, lb, freeTy);
-            if (removed)
-                lb = *removed;
-            else
-                return {std::nullopt, false, /*resourceLimitsExceeded*/ true};
-
-            ft->lowerBound = lb;
-        }
-
-        if (follow(lb) != freeTy)
-            emplaceType<BoundType>(asMutable(freeTy), lb);
-        else if (!isWithinFunction || (!FFlag::DebugLuauGreedyGeneralization && params.useCount == 1))
-            emplaceType<BoundType>(asMutable(freeTy), builtinTypes->unknownType);
-        else
-        {
-            // if the lower bound is the type in question (eg 'a <: 'a), we don't actually have a lower bound.
-            emplaceType<GenericType>(asMutable(freeTy), scope, params.polarity);
-            return {freeTy, /*wasReplacedByGeneric*/ true};
-        }
-    }
-    else
-    {
-        TypeId ub = follow(ft->upperBound);
-        if (FreeType* upperFree = getMutable<FreeType>(ub); upperFree && upperFree->lowerBound == freeTy)
-            upperFree->lowerBound = builtinTypes->neverType;
-        else
-        {
-            // If the free type appears within its own upper bound, cull that cycle.
-            std::optional<TypeId> removed = removeType(arena, builtinTypes, ub, freeTy);
-            if (removed)
-                ub = *removed;
-            else
-                return {std::nullopt, false, /*resourceLimitsExceeded*/ true};
-            ft->upperBound = ub;
-        }
-
-        if (follow(ub) != freeTy)
-            emplaceType<BoundType>(asMutable(freeTy), ub);
-        else if (!isWithinFunction || params.useCount == 1)
-            emplaceType<BoundType>(asMutable(freeTy), builtinTypes->unknownType);
-        else
-        {
-            // if the upper bound is the type in question, we don't actually have an upper bound.
-            emplaceType<GenericType>(asMutable(freeTy), scope, params.polarity);
-            return {freeTy, /*wasReplacedByGeneric*/ true};
-        }
-    }
-
-    return {freeTy, /*wasReplacedByGeneric*/ false};
-}
-
-GeneralizationResult<TypePackId> generalizeTypePack(
-    NotNull<TypeArena> arena,
-    NotNull<BuiltinTypes> builtinTypes,
-    NotNull<Scope> scope,
-    TypePackId tp,
-    const GeneralizationParams<TypePackId>& params
-)
-{
-    tp = follow(tp);
-
-    if (tp->owningArena != arena)
-        return {tp, /*wasReplacedByGeneric*/ false};
-
-    const FreeTypePack* ftp = get<FreeTypePack>(tp);
-    if (!ftp)
-        return {tp, /*wasReplacedByGeneric*/ false};
-
-    if (!subsumes(scope, ftp->scope))
-        return {tp, /*wasReplacedByGeneric*/ false};
-
-    if (1 == params.useCount)
-        emplaceTypePack<BoundTypePack>(asMutable(tp), builtinTypes->unknownTypePack);
-    else
-    {
-        emplaceTypePack<GenericTypePack>(asMutable(tp), scope, params.polarity);
-        return {tp, /*wasReplacedByGeneric*/ true};
-    }
-
-    return {tp, /*wasReplacedByGeneric*/ false};
-}
-
-void sealTable(NotNull<Scope> scope, TypeId ty)
-{
-    TableType* tableTy = getMutable<TableType>(follow(ty));
-    if (!tableTy)
-        return;
-
-    if (!subsumes(scope, tableTy->scope))
-        return;
-
-    if (tableTy->state == TableState::Unsealed || tableTy->state == TableState::Free)
-        tableTy->state = TableState::Sealed;
-}
-
 std::optional<TypeId> generalize(
     NotNull<TypeArena> arena,
     NotNull<BuiltinTypes> builtinTypes,
     NotNull<Scope> scope,
     NotNull<DenseHashSet<TypeId>> cachedTypes,
     TypeId ty,
-    std::optional<TypeId> generalizationTarget
+    bool avoidSealingTables
 )
 {
     ty = follow(ty);
@@ -1374,61 +984,7 @@ std::optional<TypeId> generalize(
     FreeTypeSearcher fts{scope, cachedTypes};
     fts.traverse(ty);
 
-    if (FFlag::LuauNonReentrantGeneralization2)
+    MutatingGeneralizer gen{arena, builtinTypes, scope, cachedTypes, std::move(fts.positiveTypes), std::move(fts.negativeTypes), avoidSealingTables};
-    {
-        FunctionType* functionTy = getMutable<FunctionType>(ty);
-        auto pushGeneric = [&](TypeId t)
-        {
-            if (functionTy)
-                functionTy->generics.push_back(t);
-        };
-
-        auto pushGenericPack = [&](TypePackId tp)
-        {
-            if (functionTy)
-                functionTy->genericPacks.push_back(tp);
-        };
-
-        for (const auto& [freeTy, params] : fts.types)
-        {
-            if (!generalizationTarget || freeTy == *generalizationTarget)
-            {
-                GeneralizationResult<TypeId> res = generalizeType(arena, builtinTypes, scope, freeTy, params);
-                if (res.resourceLimitsExceeded)
-                    return std::nullopt;
-
-                if (res && res.wasReplacedByGeneric)
-                    pushGeneric(*res.result);
-            }
-        }
-
-        for (TypeId unsealedTableTy : fts.unsealedTables)
-        {
-            if (!generalizationTarget || unsealedTableTy == *generalizationTarget)
-                sealTable(scope, unsealedTableTy);
-        }
-
-        for (const auto& [freePackId, params] : fts.typePacks)
-        {
-            TypePackId freePack = follow(freePackId);
-            if (!generalizationTarget)
-            {
-                GeneralizationResult<TypePackId> generalizedTp = generalizeTypePack(arena, builtinTypes, scope, freePack, params);
-
-                if (generalizedTp.resourceLimitsExceeded)
-                    return std::nullopt;
-
-                if (generalizedTp && generalizedTp.wasReplacedByGeneric)
-                    pushGenericPack(freePack);
-            }
-        }
-
-        TypeCacher cacher{cachedTypes};
-        cacher.traverse(ty);
-    }
-    else
-    {
-        MutatingGeneralizer gen{arena, builtinTypes, scope, cachedTypes, std::move(fts.positiveTypes), std::move(fts.negativeTypes)};
 
     gen.traverse(ty);
 
@@ -1459,202 +1015,8 @@ std::optional<TypeId> generalize(
             ftv->genericPacks.push_back(gp);
         }
     }
-    }
 
     return ty;
 }
 
-struct GenericCounter : TypeVisitor
-{
-    struct CounterState
-    {
-        size_t count = 0;
-        Polarity polarity = Polarity::None;
-    };
-
-    NotNull<DenseHashSet<TypeId>> cachedTypes;
-    DenseHashMap<TypeId, CounterState> generics{nullptr};
-    DenseHashMap<TypePackId, CounterState> genericPacks{nullptr};
-
-    Polarity polarity = Polarity::Positive;
-
-    explicit GenericCounter(NotNull<DenseHashSet<TypeId>> cachedTypes)
-        : cachedTypes(cachedTypes)
-    {
-    }
-
-    bool visit(TypeId ty, const FunctionType& ft) override
-    {
-        if (ty->persistent)
-            return false;
-
-        polarity = invert(polarity);
-        traverse(ft.argTypes);
-        polarity = invert(polarity);
-        traverse(ft.retTypes);
-
-        return false;
-    }
-
-    bool visit(TypeId ty, const TableType& tt) override
-    {
-        if (ty->persistent)
-            return false;
-
-        const Polarity previous = polarity;
-
-        for (const auto& [_name, prop] : tt.props)
-        {
-            if (prop.isReadOnly())
-                traverse(*prop.readTy);
-            else
-            {
-                LUAU_ASSERT(prop.isShared());
-
-                polarity = Polarity::Mixed;
-                traverse(prop.type());
-                polarity = previous;
-            }
-        }
-
-        if (tt.indexer)
-        {
-            polarity = Polarity::Mixed;
-            traverse(tt.indexer->indexType);
-            traverse(tt.indexer->indexResultType);
-            polarity = previous;
-        }
-
-        return false;
-    }
-
-    bool visit(TypeId ty, const ExternType&) override
-    {
-        return false;
-    }
-
-    bool visit(TypeId ty, const GenericType&) override
-    {
-        auto state = generics.find(ty);
-        if (state)
-        {
-            ++state->count;
-            state->polarity |= polarity;
-        }
-
-        return false;
-    }
-
-    bool visit(TypePackId tp, const GenericTypePack&) override
-    {
-        auto state = genericPacks.find(tp);
-        if (state)
-        {
-            ++state->count;
-            state->polarity |= polarity;
-        }
-
-        return false;
-    }
-};
-
-void pruneUnnecessaryGenerics(
-    NotNull<TypeArena> arena,
-    NotNull<BuiltinTypes> builtinTypes,
-    NotNull<Scope> scope,
-    NotNull<DenseHashSet<TypeId>> cachedTypes,
-    TypeId ty
-)
-{
-    if (!FFlag::DebugLuauGreedyGeneralization)
-        return;
-
-    ty = follow(ty);
-
-    if (ty->owningArena != arena || ty->persistent)
-        return;
-
-    FunctionType* functionTy = getMutable<FunctionType>(ty);
-
-    if (!functionTy)
-        return;
-
-    // If a generic has no explicit name and is only referred to in one place in
-    // the function's signature, it can be replaced with unknown.
-
-    GenericCounter counter{cachedTypes};
-    for (TypeId generic : functionTy->generics)
-    {
-        generic = follow(generic);
-        auto g = get<GenericType>(generic);
-        if (g && !g->explicitName)
-            counter.generics[generic] = {};
-    }
-
-    // It is sometimes the case that a pack in the generic list will become a
-    // pack that (transitively) has a generic tail.  If it does, we need to add
-    // that generic tail to the generic pack list.
-    for (size_t i = 0; i < functionTy->genericPacks.size(); ++i)
-    {
-        TypePackId genericPack = follow(functionTy->genericPacks[i]);
-
-        TypePackId tail = getTail(genericPack);
-
-        if (tail != genericPack)
-            functionTy->genericPacks.push_back(tail);
-
-        if (auto g = get<GenericTypePack>(tail); g && !g->explicitName)
-            counter.genericPacks[genericPack] = {};
-    }
-
-    counter.traverse(ty);
-
-    for (const auto& [generic, state] : counter.generics)
-    {
-        if (state.count == 1 && state.polarity != Polarity::Mixed)
-            emplaceType<BoundType>(asMutable(generic), builtinTypes->unknownType);
-    }
-
-    // Remove duplicates and types that aren't actually generics.
-    DenseHashSet<TypeId> seen{nullptr};
-    auto it = std::remove_if(
-        functionTy->generics.begin(),
-        functionTy->generics.end(),
-        [&](TypeId ty)
-        {
-            ty = follow(ty);
-            if (seen.contains(ty))
-                return true;
-            seen.insert(ty);
-
-            return !get<GenericType>(ty);
-        }
-    );
-
-    functionTy->generics.erase(it, functionTy->generics.end());
-
-    for (const auto& [genericPack, state] : counter.genericPacks)
-    {
-        if (state.count == 1)
-            emplaceTypePack<BoundTypePack>(asMutable(genericPack), builtinTypes->unknownTypePack);
-    }
-
-    DenseHashSet<TypePackId> seen2{nullptr};
-    auto it2 = std::remove_if(
-        functionTy->genericPacks.begin(),
-        functionTy->genericPacks.end(),
-        [&](TypePackId tp)
-        {
-            tp = follow(tp);
-            if (seen2.contains(tp))
-                return true;
-            seen2.insert(tp);
-
-            return !get<GenericTypePack>(tp);
-        }
-    );
-
-    functionTy->genericPacks.erase(it2, functionTy->genericPacks.end());
-}
-
 } // namespace Luau

Analysis/src/InferPolarity.cpp

@@ -1,169 +0,0 @@
-// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
-
-#include "Luau/DenseHash.h"
-#include "Luau/Polarity.h"
-#include "Luau/Scope.h"
-#include "Luau/VisitType.h"
-
-LUAU_FASTFLAG(LuauNonReentrantGeneralization2)
-
-namespace Luau
-{
-
-struct InferPolarity : TypeVisitor
-{
-    NotNull<TypeArena> arena;
-    NotNull<Scope> scope;
-
-    DenseHashMap<TypeId, Polarity> types{nullptr};
-    DenseHashMap<TypePackId, Polarity> packs{nullptr};
-
-    Polarity polarity = Polarity::Positive;
-
-    explicit InferPolarity(NotNull<TypeArena> arena, NotNull<Scope> scope)
-        : arena(arena)
-        , scope(scope)
-    {
-    }
-
-    void flip()
-    {
-        polarity = invert(polarity);
-    }
-
-    bool visit(TypeId ty, const GenericType& gt) override
-    {
-        if (ty->owningArena != arena)
-            return false;
-
-        if (subsumes(scope, gt.scope))
-            types[ty] |= polarity;
-
-        return false;
-    }
-
-    bool visit(TypeId ty, const TableType& tt) override
-    {
-        if (ty->owningArena != arena)
-            return false;
-
-        const Polarity p = polarity;
-        for (const auto& [name, prop] : tt.props)
-        {
-            if (prop.isShared())
-            {
-                polarity = Polarity::Mixed;
-                traverse(prop.type());
-            }
-            else if (prop.isReadOnly())
-            {
-                polarity = p;
-                traverse(*prop.readTy);
-            }
-            else if (prop.isWriteOnly())
-            {
-                polarity = invert(p);
-                traverse(*prop.writeTy);
-            }
-            else
-                LUAU_ASSERT(!"Unreachable");
-        }
-
-        if (tt.indexer)
-        {
-            polarity = Polarity::Mixed;
-            traverse(tt.indexer->indexType);
-            traverse(tt.indexer->indexResultType);
-        }
-
-        polarity = p;
-
-        return false;
-    }
-
-    bool visit(TypeId ty, const FunctionType& ft) override
-    {
-        if (ty->owningArena != arena)
-            return false;
-
-        const Polarity p = polarity;
-
-        polarity = Polarity::Positive;
-
-        // If these types actually occur within the function signature, their
-        // polarity will be overwritten. If not, we infer that they are phantom
-        // types.
-        for (TypeId generic : ft.generics)
-        {
-            generic = follow(generic);
-            const auto gen = get<GenericType>(generic);
-            if (gen && subsumes(scope, gen->scope))
-                types[generic] = Polarity::None;
-        }
-        for (TypePackId genericPack : ft.genericPacks)
-        {
-            genericPack = follow(genericPack);
-            const auto gen = get<GenericTypePack>(genericPack);
-            if (gen && subsumes(scope, gen->scope))
-                packs[genericPack] = Polarity::None;
-        }
-
-        flip();
-        traverse(ft.argTypes);
-        flip();
-        traverse(ft.retTypes);
-
-        polarity = p;
-
-        return false;
-    }
-
-    bool visit(TypeId, const ExternType&) override
-    {
-        return false;
-    }
-
-    bool visit(TypePackId tp, const GenericTypePack& gtp) override
-    {
-        packs[tp] |= polarity;
-        return false;
-    }
-};
-
-template<typename TID>
-static void inferGenericPolarities_(NotNull<TypeArena> arena, NotNull<Scope> scope, TID ty)
-{
-    if (!FFlag::LuauNonReentrantGeneralization2)
-        return;
-
-    InferPolarity infer{arena, scope};
-    infer.traverse(ty);
-
-    for (const auto& [ty, polarity] : infer.types)
-    {
-        auto gt = getMutable<GenericType>(ty);
-        LUAU_ASSERT(gt);
-        gt->polarity = polarity;
-    }
-
-    for (const auto& [tp, polarity] : infer.packs)
-    {
-        if (tp->owningArena != arena)
-            continue;
-        auto gp = getMutable<GenericTypePack>(tp);
-        LUAU_ASSERT(gp);
-        gp->polarity = polarity;
-    }
-}
-
-void inferGenericPolarities(NotNull<TypeArena> arena, NotNull<Scope> scope, TypeId ty)
-{
-    inferGenericPolarities_(arena, scope, ty);
-}
-
-void inferGenericPolarities(NotNull<TypeArena> arena, NotNull<Scope> scope, TypePackId tp)
-{
-    inferGenericPolarities_(arena, scope, tp);
-}
-
-} // namespace Luau

Analysis/src/Instantiation.cpp

@@ -11,6 +11,7 @@
 #include <algorithm>
 
 LUAU_FASTFLAG(LuauSolverV2)
+LUAU_FASTFLAG(LuauFreeTypesMustHaveBounds)
 
 namespace Luau
 {
@@ -49,7 +50,7 @@ bool Instantiation::ignoreChildren(TypeId ty)
 {
     if (log->getMutable<FunctionType>(ty))
         return true;
-    else if (get<ExternType>(ty))
+    else if (get<ClassType>(ty))
         return true;
     else
         return false;
@@ -60,7 +61,7 @@ TypeId Instantiation::clean(TypeId ty)
     const FunctionType* ftv = log->getMutable<FunctionType>(ty);
     LUAU_ASSERT(ftv);
 
-    FunctionType clone = FunctionType{level, ftv->argTypes, ftv->retTypes, ftv->definition, ftv->hasSelf};
+    FunctionType clone = FunctionType{level, scope, ftv->argTypes, ftv->retTypes, ftv->definition, ftv->hasSelf};
     clone.magic = ftv->magic;
     clone.tags = ftv->tags;
     clone.argNames = ftv->argNames;
@@ -119,7 +120,7 @@ bool ReplaceGenerics::ignoreChildren(TypeId ty)
         // whenever we quantify, so the vectors overlap if and only if they are equal.
         return (!generics.empty() || !genericPacks.empty()) && (ftv->generics == generics) && (ftv->genericPacks == genericPacks);
     }
-    else if (get<ExternType>(ty))
+    else if (get<ClassType>(ty))
         return true;
     else
     {
@@ -163,7 +164,7 @@ TypeId ReplaceGenerics::clean(TypeId ty)
     }
     else
     {
-        return arena->freshType(builtinTypes, scope, level);
+        return FFlag::LuauFreeTypesMustHaveBounds ? arena->freshType(builtinTypes, scope, level) : addType(FreeType{scope, level});
     }
 }
 

Analysis/src/Instantiation2.cpp

@@ -6,7 +6,7 @@ namespace Luau
 
 bool Instantiation2::ignoreChildren(TypeId ty)
 {
-    if (get<ExternType>(ty))
+    if (get<ClassType>(ty))
         return true;
 
     if (auto ftv = get<FunctionType>(ty))

Analysis/src/IostreamHelpers.cpp

@@ -193,8 +193,8 @@ static void errorToString(std::ostream& stream, const T& err)
         stream << "NormalizationTooComplex { }";
     else if constexpr (std::is_same_v<T, TypePackMismatch>)
         stream << "TypePackMismatch { wanted = '" + toString(err.wantedTp) + "', given = '" + toString(err.givenTp) + "' }";
-    else if constexpr (std::is_same_v<T, DynamicPropertyLookupOnExternTypesUnsafe>)
+    else if constexpr (std::is_same_v<T, DynamicPropertyLookupOnClassesUnsafe>)
-        stream << "DynamicPropertyLookupOnExternTypesUnsafe { " << toString(err.ty) << " }";
+        stream << "DynamicPropertyLookupOnClassesUnsafe { " << toString(err.ty) << " }";
     else if constexpr (std::is_same_v<T, UninhabitedTypeFunction>)
         stream << "UninhabitedTypeFunction { " << toString(err.ty) << " }";
     else if constexpr (std::is_same_v<T, ExplicitFunctionAnnotationRecommended>)
@@ -229,8 +229,6 @@ static void errorToString(std::ostream& stream, const T& err)
         stream << "UnexpectedTypePackInSubtyping {  tp = '" + toString(err.tp) + "' }";
     else if constexpr (std::is_same_v<T, UserDefinedTypeFunctionError>)
         stream << "UserDefinedTypeFunctionError { " << err.message << " }";
-    else if constexpr (std::is_same_v<T, ReservedIdentifier>)
-        stream << "ReservedIdentifier { " << err.name << " }";
     else if constexpr (std::is_same_v<T, CannotAssignToNever>)
     {
         stream << "CannotAssignToNever { rvalueType = '" << toString(err.rhsType) << "', reason = '" << err.reason << "', cause = { ";

Analysis/src/Linter.cpp

@@ -19,9 +19,6 @@ LUAU_FASTFLAG(LuauSolverV2)
 LUAU_FASTFLAG(LuauAttribute)
 LUAU_FASTFLAGVARIABLE(LintRedundantNativeAttribute)
 
-LUAU_FASTFLAG(LuauDeprecatedAttribute)
-LUAU_FASTFLAG(LuauStoreReturnTypesAsPackOnAst)
-
 namespace Luau
 {
 
@@ -909,11 +906,6 @@ private:
         return true;
     }
 
-    bool visit(AstTypePack* node) override
-    {
-        return FFlag::LuauStoreReturnTypesAsPackOnAst;
-    }
-
     bool visit(AstTypeReference* node) override
     {
         if (!node->prefix)
@@ -1976,11 +1968,6 @@ private:
         return true;
     }
 
-    bool visit(AstTypePack* node) override
-    {
-        return FFlag::LuauStoreReturnTypesAsPackOnAst;
-    }
-
     bool visit(AstTypeTable* node) override
     {
         if (FFlag::LuauSolverV2)
@@ -2293,57 +2280,6 @@ private:
     {
     }
 
-    bool visit(AstExprLocal* node) override
-    {
-        if (FFlag::LuauDeprecatedAttribute)
-        {
-
-            const FunctionType* fty = getFunctionType(node);
-            bool shouldReport = fty && fty->isDeprecatedFunction && !inScope(fty);
-
-            if (shouldReport)
-                report(node->location, node->local->name.value);
-        }
-
-        return true;
-    }
-
-    bool visit(AstExprGlobal* node) override
-    {
-        if (FFlag::LuauDeprecatedAttribute)
-        {
-            const FunctionType* fty = getFunctionType(node);
-            bool shouldReport = fty && fty->isDeprecatedFunction && !inScope(fty);
-
-            if (shouldReport)
-                report(node->location, node->name.value);
-        }
-
-        return true;
-    }
-
-    bool visit(AstStatLocalFunction* node) override
-    {
-        if (FFlag::LuauDeprecatedAttribute)
-        {
-            check(node->func);
-            return false;
-        }
-        else
-            return true;
-    }
-
-    bool visit(AstStatFunction* node) override
-    {
-        if (FFlag::LuauDeprecatedAttribute)
-        {
-            check(node->func);
-            return false;
-        }
-        else
-            return true;
-    }
-
     bool visit(AstExprIndexName* node) override
     {
         if (std::optional<TypeId> ty = context->getType(node->expr))
@@ -2383,39 +2319,18 @@ private:
 
     void check(AstExprIndexName* node, TypeId ty)
     {
-        if (const ExternType* cty = get<ExternType>(ty))
+        if (const ClassType* cty = get<ClassType>(ty))
         {
-            const Property* prop = lookupExternTypeProp(cty, node->index.value);
+            const Property* prop = lookupClassProp(cty, node->index.value);
 
             if (prop && prop->deprecated)
                 report(node->location, *prop, cty->name.c_str(), node->index.value);
-            else if (FFlag::LuauDeprecatedAttribute && prop)
-            {
-                if (std::optional<TypeId> ty = prop->readTy)
-                {
-                    const FunctionType* fty = get<FunctionType>(follow(ty));
-                    bool shouldReport = fty && fty->isDeprecatedFunction && !inScope(fty);
-
-                    if (shouldReport)
-                    {
-                        const char* className = nullptr;
-                        if (AstExprGlobal* global = node->expr->as<AstExprGlobal>())
-                            className = global->name.value;
-
-                        const char* functionName = node->index.value;
-
-                        report(node->location, className, functionName);
-                    }
-                }
-            }
         }
         else if (const TableType* tty = get<TableType>(ty))
         {
             auto prop = tty->props.find(node->index.value);
 
-            if (prop != tty->props.end())
+            if (prop != tty->props.end() && prop->second.deprecated)
-            {
-                if (prop->second.deprecated)
             {
                 // strip synthetic typeof() for builtin tables
                 if (tty->name && tty->name->compare(0, 7, "typeof(") == 0 && tty->name->back() == ')')
@@ -2423,26 +2338,6 @@ private:
                 else
                     report(node->location, prop->second, tty->name ? tty->name->c_str() : nullptr, node->index.value);
             }
-                else if (FFlag::LuauDeprecatedAttribute)
-                {
-                    if (std::optional<TypeId> ty = prop->second.readTy)
-                    {
-                        const FunctionType* fty = get<FunctionType>(follow(ty));
-                        bool shouldReport = fty && fty->isDeprecatedFunction && !inScope(fty);
-
-                        if (shouldReport)
-                        {
-                            const char* className = nullptr;
-                            if (AstExprGlobal* global = node->expr->as<AstExprGlobal>())
-                                className = global->name.value;
-
-                            const char* functionName = node->index.value;
-
-                            report(node->location, className, functionName);
-                        }
-                    }
-                }
-            }
         }
     }
 
@@ -2460,26 +2355,6 @@ private:
         }
     }
 
-    void check(AstExprFunction* func)
-    {
-        LUAU_ASSERT(FFlag::LuauDeprecatedAttribute);
-        LUAU_ASSERT(func);
-
-        const FunctionType* fty = getFunctionType(func);
-        bool isDeprecated = fty && fty->isDeprecatedFunction;
-
-        // If a function is deprecated, we don't want to flag its recursive uses.
-        // So we push it on a stack while its body is being analyzed.
-        // When a deprecated function is used, we check the stack to ensure that we are not inside that function.
-        if (isDeprecated)
-            pushScope(fty);
-
-        func->visit(this);
-
-        if (isDeprecated)
-            popScope(fty);
-    }
-
     void report(const Location& location, const Property& prop, const char* container, const char* field)
     {
         std::string suggestion = prop.deprecatedSuggestion.empty() ? "" : format(", use '%s' instead", prop.deprecatedSuggestion.c_str());
@@ -2489,63 +2364,6 @@ private:
         else
             emitWarning(*context, LintWarning::Code_DeprecatedApi, location, "Member '%s' is deprecated%s", field, suggestion.c_str());
     }
-
-    void report(const Location& location, const char* tableName, const char* functionName)
-    {
-        LUAU_ASSERT(FFlag::LuauDeprecatedAttribute);
-
-        if (tableName)
-            emitWarning(*context, LintWarning::Code_DeprecatedApi, location, "Member '%s.%s' is deprecated", tableName, functionName);
-        else
-            emitWarning(*context, LintWarning::Code_DeprecatedApi, location, "Member '%s' is deprecated", functionName);
-    }
-
-    void report(const Location& location, const char* functionName)
-    {
-        LUAU_ASSERT(FFlag::LuauDeprecatedAttribute);
-
-        emitWarning(*context, LintWarning::Code_DeprecatedApi, location, "Function '%s' is deprecated", functionName);
-    }
-
-    std::vector<const FunctionType*> functionTypeScopeStack;
-
-    void pushScope(const FunctionType* fty)
-    {
-        LUAU_ASSERT(FFlag::LuauDeprecatedAttribute);
-        LUAU_ASSERT(fty);
-
-        functionTypeScopeStack.push_back(fty);
-    }
-
-    void popScope(const FunctionType* fty)
-    {
-        LUAU_ASSERT(FFlag::LuauDeprecatedAttribute);
-        LUAU_ASSERT(fty);
-
-        LUAU_ASSERT(fty == functionTypeScopeStack.back());
-        functionTypeScopeStack.pop_back();
-    }
-
-    bool inScope(const FunctionType* fty) const
-    {
-        LUAU_ASSERT(FFlag::LuauDeprecatedAttribute);
-        LUAU_ASSERT(fty);
-
-        return std::find(functionTypeScopeStack.begin(), functionTypeScopeStack.end(), fty) != functionTypeScopeStack.end();
-    }
-
-    const FunctionType* getFunctionType(AstExpr* node)
-    {
-        LUAU_ASSERT(FFlag::LuauDeprecatedAttribute);
-
-        std::optional<TypeId> ty = context->getType(node);
-        if (!ty)
-            return nullptr;
-
-        const FunctionType* fty = get<FunctionType>(follow(ty));
-
-        return fty;
-    }
 };
 
 class LintTableOperations : AstVisitor

Analysis/src/Module.cpp

@@ -15,12 +15,12 @@
 #include <algorithm>
 
 LUAU_FASTFLAG(LuauSolverV2);
-LUAU_FASTFLAG(LuauRetainDefinitionAliasLocations)
+LUAU_FASTFLAGVARIABLE(LuauIncrementalAutocompleteCommentDetection)
 
 namespace Luau
 {
 
-static void defaultLogLuau(std::string_view context, std::string_view input)
+static void defaultLogLuau(std::string_view input)
 {
     // The default is to do nothing because we don't want to mess with
     // the xml parsing done by the dcr script.
@@ -38,6 +38,21 @@ void resetLogLuauProc()
     logLuau = &defaultLogLuau;
 }
 
+
+
+static bool contains_DEPRECATED(Position pos, Comment comment)
+{
+    if (comment.location.contains(pos))
+        return true;
+    else if (comment.type == Lexeme::BrokenComment && comment.location.begin <= pos) // Broken comments are broken specifically because they don't
+                                                                                     // have an end
+        return true;
+    else if (comment.type == Lexeme::Comment && comment.location.end == pos)
+        return true;
+    else
+        return false;
+}
+
 static bool contains(Position pos, Comment comment)
 {
     if (comment.location.contains(pos))
@@ -60,9 +75,12 @@ bool isWithinComment(const std::vector<Comment>& commentLocations, Position pos)
         commentLocations.end(),
         Comment{Lexeme::Comment, Location{pos, pos}},
         [](const Comment& a, const Comment& b)
+        {
+            if (FFlag::LuauIncrementalAutocompleteCommentDetection)
             {
                 if (a.type == Lexeme::Comment)
                     return a.location.end.line < b.location.end.line;
+            }
             return a.location.end < b.location.end;
         }
     );
@@ -70,7 +88,7 @@ bool isWithinComment(const std::vector<Comment>& commentLocations, Position pos)
     if (iter == commentLocations.end())
         return false;
 
-    if (contains(pos, *iter))
+    if (FFlag::LuauIncrementalAutocompleteCommentDetection ? contains(pos, *iter) : contains_DEPRECATED(pos, *iter))
         return true;
 
     // Due to the nature of std::lower_bound, it is possible that iter points at a comment that ends
@@ -154,6 +172,8 @@ struct ClonePublicInterface : Substitution
             }
 
             ftv->level = TypeLevel{0, 0};
+            if (FFlag::LuauSolverV2)
+                ftv->scope = nullptr;
         }
         else if (TableType* ttv = getMutable<TableType>(result))
         {
@@ -265,9 +285,6 @@ struct ClonePublicInterface : Substitution
 
         TypeId type = cloneType(tf.type);
 
-        if (FFlag::LuauRetainDefinitionAliasLocations)
-            return TypeFun{typeParams, typePackParams, type, tf.definitionLocation};
-        else
         return TypeFun{typeParams, typePackParams, type};
     }
 };

Analysis/src/NonStrictTypeChecker.cpp

@@ -2,7 +2,6 @@
 #include "Luau/NonStrictTypeChecker.h"
 
 #include "Luau/Ast.h"
-#include "Luau/AstQuery.h"
 #include "Luau/Common.h"
 #include "Luau/Simplify.h"
 #include "Luau/Type.h"
@@ -20,12 +19,10 @@
 #include <iostream>
 #include <iterator>
 
-LUAU_FASTFLAG(DebugLuauMagicTypes)
+LUAU_FASTFLAG(LuauFreeTypesMustHaveBounds)
-
 LUAU_FASTFLAGVARIABLE(LuauNonStrictVisitorImprovements)
 LUAU_FASTFLAGVARIABLE(LuauNewNonStrictWarnOnUnknownGlobals)
-LUAU_FASTFLAGVARIABLE(LuauNewNonStrictVisitTypes2)
+LUAU_FASTFLAGVARIABLE(LuauNonStrictFuncDefErrorFix)
-LUAU_FASTFLAG(LuauStoreReturnTypesAsPackOnAst)
 
 namespace Luau
 {
@@ -217,7 +214,7 @@ struct NonStrictTypeChecker
             return *fst;
         else if (auto ftp = get<FreeTypePack>(pack))
         {
-            TypeId result = arena->freshType(builtinTypes, ftp->scope);
+            TypeId result = FFlag::LuauFreeTypesMustHaveBounds ? arena->freshType(builtinTypes, ftp->scope) : arena->addType(FreeType{ftp->scope});
             TypePackId freeTail = arena->addTypePack(FreeTypePack{ftp->scope});
 
             TypePack* resultPack = emplaceTypePack<TypePack>(asMutable(pack));
@@ -311,7 +308,7 @@ struct NonStrictTypeChecker
             return visit(s);
         else if (auto s = stat->as<AstStatDeclareGlobal>())
             return visit(s);
-        else if (auto s = stat->as<AstStatDeclareExternType>())
+        else if (auto s = stat->as<AstStatDeclareClass>())
             return visit(s);
         else if (auto s = stat->as<AstStatError>())
             return visit(s);
@@ -337,12 +334,7 @@ struct NonStrictTypeChecker
                 // local x ; B generates the context of B without x
                 visit(local);
                 for (auto local : local->vars)
-                {
                     ctx.remove(dfg->getDef(local));
-
-                    if (FFlag::LuauNewNonStrictVisitTypes2)
-                        visit(local->annotation);
-                }
             }
             else
                 ctx = NonStrictContext::disjunction(builtinTypes, arena, visit(stat), ctx);
@@ -427,9 +419,6 @@ struct NonStrictTypeChecker
 
     NonStrictContext visit(AstStatFor* forStatement)
     {
-        if (FFlag::LuauNewNonStrictVisitTypes2)
-            visit(forStatement->var->annotation);
-
         if (FFlag::LuauNonStrictVisitorImprovements)
         {
             // TODO: throwing out context based on same principle as existing code?
@@ -449,12 +438,6 @@ struct NonStrictTypeChecker
 
     NonStrictContext visit(AstStatForIn* forInStatement)
     {
-        if (FFlag::LuauNewNonStrictVisitTypes2)
-        {
-            for (auto var : forInStatement->vars)
-                visit(var->annotation);
-        }
-
         if (FFlag::LuauNonStrictVisitorImprovements)
         {
             for (AstExpr* rhs : forInStatement->values)
@@ -503,12 +486,6 @@ struct NonStrictTypeChecker
 
     NonStrictContext visit(AstStatTypeAlias* typeAlias)
     {
-        if (FFlag::LuauNewNonStrictVisitTypes2)
-        {
-            visitGenerics(typeAlias->generics, typeAlias->genericPacks);
-            visit(typeAlias->type);
-        }
-
         return {};
     }
 
@@ -519,38 +496,16 @@ struct NonStrictTypeChecker
 
     NonStrictContext visit(AstStatDeclareFunction* declFn)
     {
-        if (FFlag::LuauNewNonStrictVisitTypes2)
-        {
-            visitGenerics(declFn->generics, declFn->genericPacks);
-            visit(declFn->params);
-            visit(declFn->retTypes);
-        }
-
         return {};
     }
 
     NonStrictContext visit(AstStatDeclareGlobal* declGlobal)
     {
-        if (FFlag::LuauNewNonStrictVisitTypes2)
-            visit(declGlobal->type);
-
         return {};
     }
 
-    NonStrictContext visit(AstStatDeclareExternType* declClass)
+    NonStrictContext visit(AstStatDeclareClass* declClass)
     {
-        if (FFlag::LuauNewNonStrictVisitTypes2)
-        {
-            if (declClass->indexer)
-            {
-                visit(declClass->indexer->indexType);
-                visit(declClass->indexer->resultType);
-            }
-
-            for (auto prop : declClass->props)
-                visit(prop.ty);
-        }
-
         return {};
     }
 
@@ -809,32 +764,19 @@ struct NonStrictTypeChecker
         for (AstLocal* local : exprFn->args)
         {
             if (std::optional<TypeId> ty = willRunTimeErrorFunctionDefinition(local, remainder))
+            {
+                if (FFlag::LuauNonStrictFuncDefErrorFix)
                 {
                     const char* debugname = exprFn->debugname.value;
                     reportError(NonStrictFunctionDefinitionError{debugname ? debugname : "", local->name.value, *ty}, local->location);
                 }
-            remainder.remove(dfg->getDef(local));
-
-            if (FFlag::LuauNewNonStrictVisitTypes2)
-                visit(local->annotation);
-        }
-
-        if (FFlag::LuauNewNonStrictVisitTypes2)
-        {
-            visitGenerics(exprFn->generics, exprFn->genericPacks);
-
-            if (FFlag::LuauStoreReturnTypesAsPackOnAst)
-                visit(exprFn->returnAnnotation);
                 else
                 {
-                if (exprFn->returnAnnotation_DEPRECATED)
+                    reportError(NonStrictFunctionDefinitionError{exprFn->debugname.value, local->name.value, *ty}, local->location);
-                    visit(*exprFn->returnAnnotation_DEPRECATED);
                 }
-
-            if (exprFn->varargAnnotation)
-                visit(exprFn->varargAnnotation);
             }
-
+            remainder.remove(dfg->getDef(local));
+        }
         return remainder;
     }
 
@@ -875,9 +817,6 @@ struct NonStrictTypeChecker
 
     NonStrictContext visit(AstExprTypeAssertion* typeAssertion)
     {
-        if (FFlag::LuauNewNonStrictVisitTypes2)
-            visit(typeAssertion->annotation);
-
         if (FFlag::LuauNonStrictVisitorImprovements)
             return visit(typeAssertion->expr, ValueContext::RValue);
         else
@@ -914,331 +853,6 @@ struct NonStrictTypeChecker
         return {};
     }
 
-    void visit(AstType* ty)
-    {
-        LUAU_ASSERT(FFlag::LuauNewNonStrictVisitTypes2);
-
-        // If this node is `nullptr`, early exit.
-        if (!ty)
-            return;
-
-        if (auto t = ty->as<AstTypeReference>())
-            return visit(t);
-        else if (auto t = ty->as<AstTypeTable>())
-            return visit(t);
-        else if (auto t = ty->as<AstTypeFunction>())
-            return visit(t);
-        else if (auto t = ty->as<AstTypeTypeof>())
-            return visit(t);
-        else if (auto t = ty->as<AstTypeUnion>())
-            return visit(t);
-        else if (auto t = ty->as<AstTypeIntersection>())
-            return visit(t);
-        else if (auto t = ty->as<AstTypeGroup>())
-            return visit(t->type);
-    }
-
-    void visit(AstTypeReference* ty)
-    {
-        // No further validation is necessary in this case. The main logic for
-        // _luau_print is contained in lookupAnnotation.
-        if (FFlag::DebugLuauMagicTypes && ty->name == "_luau_print")
-            return;
-
-        for (const AstTypeOrPack& param : ty->parameters)
-        {
-            if (param.type)
-                visit(param.type);
-            else
-                visit(param.typePack);
-        }
-
-        Scope* scope = findInnermostScope(ty->location);
-        LUAU_ASSERT(scope);
-
-        std::optional<TypeFun> alias = ty->prefix ? scope->lookupImportedType(ty->prefix->value, ty->name.value) : scope->lookupType(ty->name.value);
-
-        if (alias.has_value())
-        {
-            size_t typesRequired = alias->typeParams.size();
-            size_t packsRequired = alias->typePackParams.size();
-
-            bool hasDefaultTypes = std::any_of(
-                alias->typeParams.begin(),
-                alias->typeParams.end(),
-                [](auto&& el)
-                {
-                    return el.defaultValue.has_value();
-                }
-            );
-
-            bool hasDefaultPacks = std::any_of(
-                alias->typePackParams.begin(),
-                alias->typePackParams.end(),
-                [](auto&& el)
-                {
-                    return el.defaultValue.has_value();
-                }
-            );
-
-            if (!ty->hasParameterList)
-            {
-                if ((!alias->typeParams.empty() && !hasDefaultTypes) || (!alias->typePackParams.empty() && !hasDefaultPacks))
-                    reportError(GenericError{"Type parameter list is required"}, ty->location);
-            }
-
-            size_t typesProvided = 0;
-            size_t extraTypes = 0;
-            size_t packsProvided = 0;
-
-            for (const AstTypeOrPack& p : ty->parameters)
-            {
-                if (p.type)
-                {
-                    if (packsProvided != 0)
-                    {
-                        reportError(GenericError{"Type parameters must come before type pack parameters"}, ty->location);
-                        continue;
-                    }
-
-                    if (typesProvided < typesRequired)
-                        typesProvided += 1;
-                    else
-                        extraTypes += 1;
-                }
-                else if (p.typePack)
-                {
-                    std::optional<TypePackId> tp = lookupPackAnnotation(p.typePack);
-                    if (!tp.has_value())
-                        continue;
-
-                    if (typesProvided < typesRequired && size(*tp) == 1 && finite(*tp) && first(*tp))
-                        typesProvided += 1;
-                    else
-                        packsProvided += 1;
-                }
-            }
-
-            if (extraTypes != 0 && packsProvided == 0)
-            {
-                // Extra types are only collected into a pack if a pack is expected
-                if (packsRequired != 0)
-                    packsProvided += 1;
-                else
-                    typesProvided += extraTypes;
-            }
-
-            for (size_t i = typesProvided; i < typesRequired; ++i)
-            {
-                if (alias->typeParams[i].defaultValue)
-                    typesProvided += 1;
-            }
-
-            for (size_t i = packsProvided; i < packsRequired; ++i)
-            {
-                if (alias->typePackParams[i].defaultValue)
-                    packsProvided += 1;
-            }
-
-            if (extraTypes == 0 && packsProvided + 1 == packsRequired)
-                packsProvided += 1;
-
-
-            if (typesProvided != typesRequired || packsProvided != packsRequired)
-            {
-                reportError(
-                    IncorrectGenericParameterCount{
-                        /* name */ ty->name.value,
-                        /* typeFun */ *alias,
-                        /* actualParameters */ typesProvided,
-                        /* actualPackParameters */ packsProvided,
-                    },
-                    ty->location
-                );
-            }
-        }
-        else
-        {
-            if (scope->lookupPack(ty->name.value))
-            {
-                reportError(
-                    SwappedGenericTypeParameter{
-                        ty->name.value,
-                        SwappedGenericTypeParameter::Kind::Type,
-                    },
-                    ty->location
-                );
-            }
-            else
-            {
-                std::string symbol = "";
-                if (ty->prefix)
-                {
-                    symbol += (*(ty->prefix)).value;
-                    symbol += ".";
-                }
-                symbol += ty->name.value;
-
-                reportError(UnknownSymbol{symbol, UnknownSymbol::Context::Type}, ty->location);
-            }
-        }
-    }
-
-    void visit(AstTypeTable* table)
-    {
-        if (table->indexer)
-        {
-            visit(table->indexer->indexType);
-            visit(table->indexer->resultType);
-        }
-
-        for (auto prop : table->props)
-            visit(prop.type);
-    }
-
-    void visit(AstTypeFunction* function)
-    {
-        visit(function->argTypes);
-        visit(function->returnTypes);
-    }
-
-    void visit(AstTypeTypeof* typeOf)
-    {
-        visit(typeOf->expr, ValueContext::RValue);
-    }
-
-    void visit(AstTypeUnion* unionType)
-    {
-        for (auto typ : unionType->types)
-            visit(typ);
-    }
-
-    void visit(AstTypeIntersection* intersectionType)
-    {
-        for (auto typ : intersectionType->types)
-            visit(typ);
-    }
-
-    void visit(AstTypeList& list)
-    {
-        for (auto typ : list.types)
-            visit(typ);
-        if (list.tailType)
-            visit(list.tailType);
-    }
-
-    void visit(AstTypePack* pack)
-    {
-        LUAU_ASSERT(FFlag::LuauNewNonStrictVisitTypes2);
-
-        // If there is no pack node, early exit.
-        if (!pack)
-            return;
-
-        if (auto p = pack->as<AstTypePackExplicit>())
-            return visit(p);
-        else if (auto p = pack->as<AstTypePackVariadic>())
-            return visit(p);
-        else if (auto p = pack->as<AstTypePackGeneric>())
-            return visit(p);
-    }
-
-    void visit(AstTypePackExplicit* tp)
-    {
-        for (AstType* type : tp->typeList.types)
-            visit(type);
-
-        if (tp->typeList.tailType)
-            visit(tp->typeList.tailType);
-    }
-
-    void visit(AstTypePackVariadic* tp)
-    {
-        visit(tp->variadicType);
-    }
-
-    void visit(AstTypePackGeneric* tp)
-    {
-        Scope* scope = findInnermostScope(tp->location);
-        LUAU_ASSERT(scope);
-
-        std::optional<TypePackId> alias = scope->lookupPack(tp->genericName.value);
-        if (!alias.has_value())
-        {
-            if (scope->lookupType(tp->genericName.value))
-            {
-                reportError(
-                    SwappedGenericTypeParameter{
-                        tp->genericName.value,
-                        SwappedGenericTypeParameter::Kind::Pack,
-                    },
-                    tp->location
-                );
-            }
-        }
-        else
-        {
-            reportError(UnknownSymbol{tp->genericName.value, UnknownSymbol::Context::Type}, tp->location);
-        }
-    }
-
-    void visitGenerics(AstArray<AstGenericType*> generics, AstArray<AstGenericTypePack*> genericPacks)
-    {
-        DenseHashSet<AstName> seen{AstName{}};
-
-        for (const auto* g : generics)
-        {
-            if (seen.contains(g->name))
-                reportError(DuplicateGenericParameter{g->name.value}, g->location);
-            else
-                seen.insert(g->name);
-
-            if (g->defaultValue)
-                visit(g->defaultValue);
-        }
-
-        for (const auto* g : genericPacks)
-        {
-            if (seen.contains(g->name))
-                reportError(DuplicateGenericParameter{g->name.value}, g->location);
-            else
-                seen.insert(g->name);
-
-            if (g->defaultValue)
-                visit(g->defaultValue);
-        }
-    }
-
-    Scope* findInnermostScope(Location location) const
-    {
-        Scope* bestScope = module->getModuleScope().get();
-
-        bool didNarrow;
-        do
-        {
-            didNarrow = false;
-            for (auto scope : bestScope->children)
-            {
-                if (scope->location.encloses(location))
-                {
-                    bestScope = scope.get();
-                    didNarrow = true;
-                    break;
-                }
-            }
-        } while (didNarrow && bestScope->children.size() > 0);
-
-        return bestScope;
-    }
-
-    std::optional<TypePackId> lookupPackAnnotation(AstTypePack* annotation) const
-    {
-        TypePackId* tp = module->astResolvedTypePacks.find(annotation);
-        if (tp != nullptr)
-            return {follow(*tp)};
-        return {};
-    }
-
     void reportError(TypeErrorData data, const Location& location)
     {
         module->errors.emplace_back(location, module->name, std::move(data));

Analysis/src/Normalize.cpp

@@ -19,10 +19,10 @@ LUAU_FASTFLAGVARIABLE(DebugLuauCheckNormalizeInvariant)
 
 LUAU_FASTINTVARIABLE(LuauNormalizeCacheLimit, 100000)
 LUAU_FASTINTVARIABLE(LuauNormalizeIntersectionLimit, 200)
-LUAU_FASTINTVARIABLE(LuauNormalizeUnionLimit, 100)
 LUAU_FASTFLAG(LuauSolverV2)
+LUAU_FASTFLAGVARIABLE(LuauNormalizeNegationFix)
 LUAU_FASTFLAGVARIABLE(LuauFixInfiniteRecursionInNormalization)
-LUAU_FASTFLAGVARIABLE(LuauNormalizationCatchMetatableCycles)
+LUAU_FASTFLAGVARIABLE(LuauNormalizedBufferIsNotUnknown)
 
 namespace Luau
 {
@@ -249,23 +249,23 @@ bool isSubtype(const NormalizedStringType& subStr, const NormalizedStringType& s
     return true;
 }
 
-void NormalizedExternType::pushPair(TypeId ty, TypeIds negations)
+void NormalizedClassType::pushPair(TypeId ty, TypeIds negations)
 {
-    auto result = externTypes.insert(std::make_pair(ty, std::move(negations)));
+    auto result = classes.insert(std::make_pair(ty, std::move(negations)));
     if (result.second)
         ordering.push_back(ty);
-    LUAU_ASSERT(ordering.size() == externTypes.size());
+    LUAU_ASSERT(ordering.size() == classes.size());
 }
 
-void NormalizedExternType::resetToNever()
+void NormalizedClassType::resetToNever()
 {
     ordering.clear();
-    externTypes.clear();
+    classes.clear();
 }
 
-bool NormalizedExternType::isNever() const
+bool NormalizedClassType::isNever() const
 {
-    return externTypes.empty();
+    return classes.empty();
 }
 
 void NormalizedFunctionType::resetToTop()
@@ -304,17 +304,19 @@ bool NormalizedType::isUnknown() const
 
     // Otherwise, we can still be unknown!
     bool hasAllPrimitives = isPrim(booleans, PrimitiveType::Boolean) && isPrim(nils, PrimitiveType::NilType) && isNumber(numbers) &&
-                            strings.isString() && isThread(threads) && isBuffer(buffers);
+                            strings.isString() &&
+                            (FFlag::LuauNormalizedBufferIsNotUnknown ? isThread(threads) && isBuffer(buffers)
+                                                                     : isPrim(threads, PrimitiveType::Thread) && isThread(threads));
 
     // Check is class
-    bool isTopExternType = false;
+    bool isTopClass = false;
-    for (const auto& [t, disj] : externTypes.externTypes)
+    for (auto [t, disj] : classes.classes)
     {
-        if (auto ct = get<ExternType>(t))
+        if (auto ct = get<ClassType>(t))
         {
             if (ct->name == "class" && disj.empty())
             {
-                isTopExternType = true;
+                isTopClass = true;
                 break;
             }
         }
@@ -330,24 +332,24 @@ bool NormalizedType::isUnknown() const
         }
     }
     // any = unknown or error ==> we need to make sure we have all the unknown components, but not errors
-    return get<NeverType>(errors) && hasAllPrimitives && isTopExternType && isTopTable && functions.isTop;
+    return get<NeverType>(errors) && hasAllPrimitives && isTopClass && isTopTable && functions.isTop;
 }
 
 bool NormalizedType::isExactlyNumber() const
 {
-    return hasNumbers() && !hasTops() && !hasBooleans() && !hasExternTypes() && !hasErrors() && !hasNils() && !hasStrings() && !hasThreads() &&
+    return hasNumbers() && !hasTops() && !hasBooleans() && !hasClasses() && !hasErrors() && !hasNils() && !hasStrings() && !hasThreads() &&
            !hasBuffers() && !hasTables() && !hasFunctions() && !hasTyvars();
 }
 
 bool NormalizedType::isSubtypeOfString() const
 {
-    return hasStrings() && !hasTops() && !hasBooleans() && !hasExternTypes() && !hasErrors() && !hasNils() && !hasNumbers() && !hasThreads() &&
+    return hasStrings() && !hasTops() && !hasBooleans() && !hasClasses() && !hasErrors() && !hasNils() && !hasNumbers() && !hasThreads() &&
            !hasBuffers() && !hasTables() && !hasFunctions() && !hasTyvars();
 }
 
 bool NormalizedType::isSubtypeOfBooleans() const
 {
-    return hasBooleans() && !hasTops() && !hasExternTypes() && !hasErrors() && !hasNils() && !hasNumbers() && !hasStrings() && !hasThreads() &&
+    return hasBooleans() && !hasTops() && !hasClasses() && !hasErrors() && !hasNils() && !hasNumbers() && !hasStrings() && !hasThreads() &&
            !hasBuffers() && !hasTables() && !hasFunctions() && !hasTyvars();
 }
 
@@ -380,9 +382,9 @@ bool NormalizedType::hasBooleans() const
     return !get<NeverType>(booleans);
 }
 
-bool NormalizedType::hasExternTypes() const
+bool NormalizedType::hasClasses() const
 {
-    return !externTypes.isNever();
+    return !classes.isNever();
 }
 
 bool NormalizedType::hasErrors() const
@@ -440,7 +442,7 @@ bool NormalizedType::isFalsy() const
             hasAFalse = !bs->value;
     }
 
-    return (hasAFalse || hasNils()) && (!hasTops() && !hasExternTypes() && !hasErrors() && !hasNumbers() && !hasStrings() && !hasThreads() &&
+    return (hasAFalse || hasNils()) && (!hasTops() && !hasClasses() && !hasErrors() && !hasNumbers() && !hasStrings() && !hasThreads() &&
                                         !hasBuffers() && !hasTables() && !hasFunctions() && !hasTyvars());
 }
 
@@ -452,7 +454,7 @@ bool NormalizedType::isTruthy() const
 static bool isShallowInhabited(const NormalizedType& norm)
 {
     // This test is just a shallow check, for example it returns `true` for `{ p : never }`
-    return !get<NeverType>(norm.tops) || !get<NeverType>(norm.booleans) || !norm.externTypes.isNever() || !get<NeverType>(norm.errors) ||
+    return !get<NeverType>(norm.tops) || !get<NeverType>(norm.booleans) || !norm.classes.isNever() || !get<NeverType>(norm.errors) ||
            !get<NeverType>(norm.nils) || !get<NeverType>(norm.numbers) || !norm.strings.isNever() || !get<NeverType>(norm.threads) ||
            !get<NeverType>(norm.buffers) || !norm.functions.isNever() || !norm.tables.empty() || !norm.tyvars.empty();
 }
@@ -471,7 +473,7 @@ NormalizationResult Normalizer::isInhabited(const NormalizedType* norm, Set<Type
         return NormalizationResult::HitLimits;
 
     if (!get<NeverType>(norm->tops) || !get<NeverType>(norm->booleans) || !get<NeverType>(norm->errors) || !get<NeverType>(norm->nils) ||
-        !get<NeverType>(norm->numbers) || !get<NeverType>(norm->threads) || !get<NeverType>(norm->buffers) || !norm->externTypes.isNever() ||
+        !get<NeverType>(norm->numbers) || !get<NeverType>(norm->threads) || !get<NeverType>(norm->buffers) || !norm->classes.isNever() ||
         !norm->strings.isNever() || !norm->functions.isNever())
         return NormalizationResult::True;
 
@@ -579,7 +581,7 @@ NormalizationResult Normalizer::isIntersectionInhabited(TypeId left, TypeId righ
 {
     left = follow(left);
     right = follow(right);
-    // We're asking if intersection is inhabited between left and right but we've already seen them ....
+    // We're asking if intersection is inahbited between left and right but we've already seen them ....
 
     if (cacheInhabitance)
     {
@@ -619,13 +621,13 @@ static int tyvarIndex(TypeId ty)
         return 0;
 }
 
-static bool isTop(NotNull<BuiltinTypes> builtinTypes, const NormalizedExternType& externTypes)
+static bool isTop(NotNull<BuiltinTypes> builtinTypes, const NormalizedClassType& classes)
 {
-    if (externTypes.externTypes.size() != 1)
+    if (classes.classes.size() != 1)
         return false;
 
-    auto first = externTypes.externTypes.begin();
+    auto first = classes.classes.begin();
-    if (first->first != builtinTypes->externType)
+    if (first->first != builtinTypes->classType)
         return false;
 
     if (!first->second.empty())
@@ -634,11 +636,11 @@ static bool isTop(NotNull<BuiltinTypes> builtinTypes, const NormalizedExternType
     return true;
 }
 
-static void resetToTop(NotNull<BuiltinTypes> builtinTypes, NormalizedExternType& externTypes)
+static void resetToTop(NotNull<BuiltinTypes> builtinTypes, NormalizedClassType& classes)
 {
-    externTypes.ordering.clear();
+    classes.ordering.clear();
-    externTypes.externTypes.clear();
+    classes.classes.clear();
-    externTypes.pushPair(builtinTypes->externType, TypeIds{});
+    classes.pushPair(builtinTypes->classType, TypeIds{});
 }
 
 #ifdef LUAU_ASSERTENABLED
@@ -762,50 +764,50 @@ static bool areNormalizedTables(const TypeIds& tys)
     return true;
 }
 
-static bool areNormalizedExternTypes(const NormalizedExternType& tys)
+static bool areNormalizedClasses(const NormalizedClassType& tys)
 {
-    for (const auto& [ty, negations] : tys.externTypes)
+    for (const auto& [ty, negations] : tys.classes)
     {
-        const ExternType* etv = get<ExternType>(ty);
+        const ClassType* ctv = get<ClassType>(ty);
-        if (!etv)
+        if (!ctv)
         {
             return false;
         }
 
         for (TypeId negation : negations)
         {
-            const ExternType* nctv = get<ExternType>(negation);
+            const ClassType* nctv = get<ClassType>(negation);
             if (!nctv)
             {
                 return false;
             }
 
-            if (!isSubclass(nctv, etv))
+            if (!isSubclass(nctv, ctv))
             {
                 return false;
             }
         }
 
-        for (const auto& [otherTy, otherNegations] : tys.externTypes)
+        for (const auto& [otherTy, otherNegations] : tys.classes)
         {
             if (otherTy == ty)
                 continue;
 
-            const ExternType* octv = get<ExternType>(otherTy);
+            const ClassType* octv = get<ClassType>(otherTy);
             if (!octv)
             {
                 return false;
             }
 
-            if (isSubclass(etv, octv))
+            if (isSubclass(ctv, octv))
             {
-                auto iss = [etv](TypeId t)
+                auto iss = [ctv](TypeId t)
                 {
-                    const ExternType* c = get<ExternType>(t);
+                    const ClassType* c = get<ClassType>(t);
                     if (!c)
                         return false;
 
-                    return isSubclass(etv, c);
+                    return isSubclass(ctv, c);
                 };
 
                 if (!std::any_of(otherNegations.begin(), otherNegations.end(), iss))
@@ -847,7 +849,7 @@ static void assertInvariant(const NormalizedType& norm)
 
     LUAU_ASSERT(isNormalizedTop(norm.tops));
     LUAU_ASSERT(isNormalizedBoolean(norm.booleans));
-    LUAU_ASSERT(areNormalizedExternTypes(norm.externTypes));
+    LUAU_ASSERT(areNormalizedClasses(norm.classes));
     LUAU_ASSERT(isNormalizedError(norm.errors));
     LUAU_ASSERT(isNormalizedNil(norm.nils));
     LUAU_ASSERT(isNormalizedNumber(norm.numbers));
@@ -988,7 +990,7 @@ void Normalizer::clearNormal(NormalizedType& norm)
 {
     norm.tops = builtinTypes->neverType;
     norm.booleans = builtinTypes->neverType;
-    norm.externTypes.resetToNever();
+    norm.classes.resetToNever();
     norm.errors = builtinTypes->neverType;
     norm.nils = builtinTypes->neverType;
     norm.numbers = builtinTypes->neverType;
@@ -1138,17 +1140,17 @@ TypeId Normalizer::unionOfBools(TypeId here, TypeId there)
     return builtinTypes->booleanType;
 }
 
-void Normalizer::unionExternTypesWithExternType(TypeIds& heres, TypeId there)
+void Normalizer::unionClassesWithClass(TypeIds& heres, TypeId there)
 {
     if (heres.count(there))
         return;
 
-    const ExternType* tctv = get<ExternType>(there);
+    const ClassType* tctv = get<ClassType>(there);
 
     for (auto it = heres.begin(); it != heres.end();)
     {
         TypeId here = *it;
-        const ExternType* hctv = get<ExternType>(here);
+        const ClassType* hctv = get<ClassType>(here);
         if (isSubclass(tctv, hctv))
             return;
         else if (isSubclass(hctv, tctv))
@@ -1160,16 +1162,16 @@ void Normalizer::unionExternTypesWithExternType(TypeIds& heres, TypeId there)
     heres.insert(there);
 }
 
-void Normalizer::unionExternTypes(TypeIds& heres, const TypeIds& theres)
+void Normalizer::unionClasses(TypeIds& heres, const TypeIds& theres)
 {
     for (TypeId there : theres)
-        unionExternTypesWithExternType(heres, there);
+        unionClassesWithClass(heres, there);
 }
 
 static bool isSubclass(TypeId test, TypeId parent)
 {
-    const ExternType* testCtv = get<ExternType>(test);
+    const ClassType* testCtv = get<ClassType>(test);
-    const ExternType* parentCtv = get<ExternType>(parent);
+    const ClassType* parentCtv = get<ClassType>(parent);
 
     LUAU_ASSERT(testCtv);
     LUAU_ASSERT(parentCtv);
@@ -1177,12 +1179,12 @@ static bool isSubclass(TypeId test, TypeId parent)
     return isSubclass(testCtv, parentCtv);
 }
 
-void Normalizer::unionExternTypesWithExternType(NormalizedExternType& heres, TypeId there)
+void Normalizer::unionClassesWithClass(NormalizedClassType& heres, TypeId there)
 {
     for (auto it = heres.ordering.begin(); it != heres.ordering.end();)
     {
         TypeId hereTy = *it;
-        TypeIds& hereNegations = heres.externTypes.at(hereTy);
+        TypeIds& hereNegations = heres.classes.at(hereTy);
 
         // If the incoming class is a subclass of another class in the map, we
         // must ensure that it is negated by one of the negations in the same
@@ -1204,7 +1206,7 @@ void Normalizer::unionExternTypesWithExternType(NormalizedExternType& heres, Typ
                 }
                 // If the incoming class is a superclass of one of the
                 // negations, then the negation no longer applies and must be
-                // removed. This is also true if they are equal. Since extern types
+                // removed. This is also true if they are equal. Since classes
                 // are, at this time, entirely persistent (we do not clone
                 // them), a pointer identity check is sufficient.
                 else if (isSubclass(hereNegation, there))
@@ -1231,7 +1233,7 @@ void Normalizer::unionExternTypesWithExternType(NormalizedExternType& heres, Typ
         {
             TypeIds negations = std::move(hereNegations);
             it = heres.ordering.erase(it);
-            heres.externTypes.erase(hereTy);
+            heres.classes.erase(hereTy);
 
             heres.pushPair(there, std::move(negations));
             return;
@@ -1248,10 +1250,10 @@ void Normalizer::unionExternTypesWithExternType(NormalizedExternType& heres, Typ
     heres.pushPair(there, TypeIds{});
 }
 
-void Normalizer::unionExternTypes(NormalizedExternType& heres, const NormalizedExternType& theres)
+void Normalizer::unionClasses(NormalizedClassType& heres, const NormalizedClassType& theres)
 {
-    // This method bears much similarity with unionExternTypesWithExternType, but is
+    // This method bears much similarity with unionClassesWithClass, but is
-    // solving a more general problem. In unionExternTypesWithExternType, we are dealing
+    // solving a more general problem. In unionClassesWithClass, we are dealing
     // with a singular positive type. Since it's one type, we can use early
     // returns as control flow. Since it's guaranteed to be positive, we do not
     // have negations to worry about combining. The two aspects combine to make
@@ -1260,9 +1262,9 @@ void Normalizer::unionExternTypes(NormalizedExternType& heres, const NormalizedE
 
     for (const TypeId thereTy : theres.ordering)
     {
-        const TypeIds& thereNegations = theres.externTypes.at(thereTy);
+        const TypeIds& thereNegations = theres.classes.at(thereTy);
 
-        // If it happens that there are _no_ extern types in the current map, or the
+        // If it happens that there are _no_ classes in the current map, or the
         // incoming class is completely unrelated to any class in the current
         // map, we must insert the incoming pair as-is.
         bool insert = true;
@@ -1270,7 +1272,7 @@ void Normalizer::unionExternTypes(NormalizedExternType& heres, const NormalizedE
         for (auto it = heres.ordering.begin(); it != heres.ordering.end();)
         {
             TypeId hereTy = *it;
-            TypeIds& hereNegations = heres.externTypes.at(hereTy);
+            TypeIds& hereNegations = heres.classes.at(hereTy);
 
             if (isSubclass(thereTy, hereTy))
             {
@@ -1294,7 +1296,7 @@ void Normalizer::unionExternTypes(NormalizedExternType& heres, const NormalizedE
                     // If the incoming class is a superclass of one of the
                     // negations, then the negation no longer applies and must
                     // be removed. This is also true if they are equal. Since
-                    // extern types are, at this time, entirely persistent (we do not
+                    // classes are, at this time, entirely persistent (we do not
                     // clone them), a pointer identity check is sufficient.
                     else if (isSubclass(hereNegateTy, thereTy))
                     {
@@ -1319,17 +1321,17 @@ void Normalizer::unionExternTypes(NormalizedExternType& heres, const NormalizedE
             else if (isSubclass(hereTy, thereTy))
             {
                 TypeIds negations = std::move(hereNegations);
-                unionExternTypes(negations, thereNegations);
+                unionClasses(negations, thereNegations);
 
                 it = heres.ordering.erase(it);
-                heres.externTypes.erase(hereTy);
+                heres.classes.erase(hereTy);
                 heres.pushPair(thereTy, std::move(negations));
                 insert = false;
                 break;
             }
             else if (hereTy == thereTy)
             {
-                unionExternTypes(hereNegations, thereNegations);
+                unionClasses(hereNegations, thereNegations);
                 insert = false;
                 break;
             }
@@ -1685,12 +1687,8 @@ NormalizationResult Normalizer::unionNormals(NormalizedType& here, const Normali
             return res;
     }
 
-    // Limit based on worst-case expansion of the function unions
-    if (here.functions.parts.size() * there.functions.parts.size() >= size_t(FInt::LuauNormalizeUnionLimit))
-        return NormalizationResult::HitLimits;
-
     here.booleans = unionOfBools(here.booleans, there.booleans);
-    unionExternTypes(here.externTypes, there.externTypes);
+    unionClasses(here.classes, there.classes);
 
     here.errors = (get<NeverType>(there.errors) ? here.errors : there.errors);
     here.nils = (get<NeverType>(there.nils) ? here.nils : there.nils);
@@ -1700,7 +1698,6 @@ NormalizationResult Normalizer::unionNormals(NormalizedType& here, const Normali
     here.buffers = (get<NeverType>(there.buffers) ? here.buffers : there.buffers);
     unionFunctions(here.functions, there.functions);
     unionTables(here.tables, there.tables);
-
     return NormalizationResult::True;
 }
 
@@ -1740,7 +1737,7 @@ NormalizationResult Normalizer::intersectNormalWithNegationTy(TypeId toNegate, N
     return NormalizationResult::True;
 }
 
-// See above for an explanation of `ignoreSmallerTyvars`.
+// See above for an explaination of `ignoreSmallerTyvars`.
 NormalizationResult Normalizer::unionNormalWithTy(
     NormalizedType& here,
     TypeId there,
@@ -1830,8 +1827,8 @@ NormalizationResult Normalizer::unionNormalWithTy(
         unionFunctionsWithFunction(here.functions, there);
     else if (get<TableType>(there) || get<MetatableType>(there))
         unionTablesWithTable(here.tables, there);
-    else if (get<ExternType>(there))
+    else if (get<ClassType>(there))
-        unionExternTypesWithExternType(here.externTypes, there);
+        unionClassesWithClass(here.classes, there);
     else if (get<ErrorType>(there))
         here.errors = there;
     else if (const PrimitiveType* ptv = get<PrimitiveType>(there))
@@ -1944,29 +1941,29 @@ std::optional<NormalizedType> Normalizer::negateNormal(const NormalizedType& her
             result.booleans = builtinTypes->trueType;
     }
 
-    if (here.externTypes.isNever())
+    if (here.classes.isNever())
     {
-        resetToTop(builtinTypes, result.externTypes);
+        resetToTop(builtinTypes, result.classes);
     }
-    else if (isTop(builtinTypes, result.externTypes))
+    else if (isTop(builtinTypes, result.classes))
     {
-        result.externTypes.resetToNever();
+        result.classes.resetToNever();
     }
     else
     {
         TypeIds rootNegations{};
 
-        for (const auto& [hereParent, hereNegations] : here.externTypes.externTypes)
+        for (const auto& [hereParent, hereNegations] : here.classes.classes)
         {
-            if (hereParent != builtinTypes->externType)
+            if (hereParent != builtinTypes->classType)
                 rootNegations.insert(hereParent);
 
             for (TypeId hereNegation : hereNegations)
-                unionExternTypesWithExternType(result.externTypes, hereNegation);
+                unionClassesWithClass(result.classes, hereNegation);
         }
 
         if (!rootNegations.empty())
-            result.externTypes.pushPair(builtinTypes->externType, rootNegations);
+            result.classes.pushPair(builtinTypes->classType, rootNegations);
     }
 
     result.nils = get<NeverType>(here.nils) ? builtinTypes->nilType : builtinTypes->neverType;
@@ -2144,7 +2141,7 @@ TypeId Normalizer::intersectionOfBools(TypeId here, TypeId there)
         return there;
 }
 
-void Normalizer::intersectExternTypes(NormalizedExternType& heres, const NormalizedExternType& theres)
+void Normalizer::intersectClasses(NormalizedClassType& heres, const NormalizedClassType& theres)
 {
     if (theres.isNever())
     {
@@ -2178,12 +2175,12 @@ void Normalizer::intersectExternTypes(NormalizedExternType& heres, const Normali
     //   declare the result of the intersection operation to be never.
     for (const TypeId thereTy : theres.ordering)
     {
-        const TypeIds& thereNegations = theres.externTypes.at(thereTy);
+        const TypeIds& thereNegations = theres.classes.at(thereTy);
 
         for (auto it = heres.ordering.begin(); it != heres.ordering.end();)
         {
             TypeId hereTy = *it;
-            TypeIds& hereNegations = heres.externTypes.at(hereTy);
+            TypeIds& hereNegations = heres.classes.at(hereTy);
 
             if (isSubclass(thereTy, hereTy))
             {
@@ -2206,10 +2203,10 @@ void Normalizer::intersectExternTypes(NormalizedExternType& heres, const Normali
                     }
                 }
 
-                unionExternTypes(negations, thereNegations);
+                unionClasses(negations, thereNegations);
 
                 it = heres.ordering.erase(it);
-                heres.externTypes.erase(hereTy);
+                heres.classes.erase(hereTy);
                 heres.pushPair(thereTy, std::move(negations));
                 break;
             }
@@ -2234,15 +2231,15 @@ void Normalizer::intersectExternTypes(NormalizedExternType& heres, const Normali
                 {
                     if (isSubclass(hereTy, *nIt))
                     {
-                        // eg SomeExternType & (class & ~SomeExternType)
+                        // eg SomeClass & (class & ~SomeClass)
-                        // or SomeExternType & (class & ~ParentExternType)
+                        // or SomeClass & (class & ~ParentClass)
-                        heres.externTypes.erase(hereTy);
+                        heres.classes.erase(hereTy);
                         it = heres.ordering.erase(it);
                         erasedHere = true;
                         break;
                     }
 
-                    // eg SomeExternType & (class & ~Unrelated)
+                    // eg SomeClass & (class & ~Unrelated)
                     if (!isSubclass(*nIt, hereTy))
                         nIt = negations.erase(nIt);
                     else
@@ -2251,30 +2248,30 @@ void Normalizer::intersectExternTypes(NormalizedExternType& heres, const Normali
 
                 if (!erasedHere)
                 {
-                    unionExternTypes(hereNegations, negations);
+                    unionClasses(hereNegations, negations);
                     ++it;
                 }
             }
             else if (hereTy == thereTy)
             {
-                unionExternTypes(hereNegations, thereNegations);
+                unionClasses(hereNegations, thereNegations);
                 break;
             }
             else
             {
                 it = heres.ordering.erase(it);
-                heres.externTypes.erase(hereTy);
+                heres.classes.erase(hereTy);
             }
         }
     }
 }
 
-void Normalizer::intersectExternTypesWithExternType(NormalizedExternType& heres, TypeId there)
+void Normalizer::intersectClassesWithClass(NormalizedClassType& heres, TypeId there)
 {
     for (auto it = heres.ordering.begin(); it != heres.ordering.end();)
     {
         TypeId hereTy = *it;
-        const TypeIds& hereNegations = heres.externTypes.at(hereTy);
+        const TypeIds& hereNegations = heres.classes.at(hereTy);
 
         // If the incoming class _is_ the current class, we skip it. Maybe
         // another entry will have a different story. We check for this first
@@ -2319,7 +2316,7 @@ void Normalizer::intersectExternTypesWithExternType(NormalizedExternType& heres,
             }
 
             it = heres.ordering.erase(it);
-            heres.externTypes.erase(hereTy);
+            heres.classes.erase(hereTy);
             if (!emptyIntersectWithNegation)
                 heres.pushPair(there, std::move(negations));
             break;
@@ -2335,7 +2332,7 @@ void Normalizer::intersectExternTypesWithExternType(NormalizedExternType& heres,
         else
         {
             it = heres.ordering.erase(it);
-            heres.externTypes.erase(hereTy);
+            heres.classes.erase(hereTy);
         }
     }
 }
@@ -3055,7 +3052,7 @@ NormalizationResult Normalizer::intersectTyvarsWithTy(
     return NormalizationResult::True;
 }
 
-// See above for an explanation of `ignoreSmallerTyvars`.
+// See above for an explaination of `ignoreSmallerTyvars`.
 NormalizationResult Normalizer::intersectNormals(NormalizedType& here, const NormalizedType& there, int ignoreSmallerTyvars)
 {
     RecursionCounter _rc(&sharedState->counters.recursionCount);
@@ -3073,17 +3070,14 @@ NormalizationResult Normalizer::intersectNormals(NormalizedType& here, const Nor
         return unionNormals(here, there, ignoreSmallerTyvars);
     }
 
-    // Limit based on worst-case expansion of the table/function intersections
+    // Limit based on worst-case expansion of the table intersection
     // This restriction can be relaxed when table intersection simplification is improved
     if (here.tables.size() * there.tables.size() >= size_t(FInt::LuauNormalizeIntersectionLimit))
         return NormalizationResult::HitLimits;
 
-    if (here.functions.parts.size() * there.functions.parts.size() >= size_t(FInt::LuauNormalizeIntersectionLimit))
-        return NormalizationResult::HitLimits;
-
     here.booleans = intersectionOfBools(here.booleans, there.booleans);
 
-    intersectExternTypes(here.externTypes, there.externTypes);
+    intersectClasses(here.classes, there.classes);
     here.errors = (get<NeverType>(there.errors) ? there.errors : here.errors);
     here.nils = (get<NeverType>(there.nils) ? there.nils : here.nils);
     here.numbers = (get<NeverType>(there.numbers) ? there.numbers : here.numbers);
@@ -3205,18 +3199,18 @@ NormalizationResult Normalizer::intersectNormalWithTy(
         intersectTablesWithTable(tables, there, seenTablePropPairs, seenSetTypes);
         here.tables = std::move(tables);
     }
-    else if (get<ExternType>(there))
+    else if (get<ClassType>(there))
     {
-        NormalizedExternType nct = std::move(here.externTypes);
+        NormalizedClassType nct = std::move(here.classes);
         clearNormal(here);
-        intersectExternTypesWithExternType(nct, there);
+        intersectClassesWithClass(nct, there);
-        here.externTypes = std::move(nct);
+        here.classes = std::move(nct);
     }
     else if (get<ErrorType>(there))
     {
         TypeId errors = here.errors;
         clearNormal(here);
-        here.errors = get<ErrorType>(errors) ? errors : there;
+        here.errors = errors;
     }
     else if (const PrimitiveType* ptv = get<PrimitiveType>(there))
     {
@@ -3274,7 +3268,7 @@ NormalizationResult Normalizer::intersectNormalWithTy(
             subtractPrimitive(here, ntv->ty);
         else if (const SingletonType* stv = get<SingletonType>(t))
             subtractSingleton(here, follow(ntv->ty));
-        else if (get<ExternType>(t))
+        else if (get<ClassType>(t))
         {
             NormalizationResult res = intersectNormalWithNegationTy(t, here);
             if (shouldEarlyExit(res))
@@ -3313,16 +3307,11 @@ NormalizationResult Normalizer::intersectNormalWithTy(
             clearNormal(here);
             return NormalizationResult::True;
         }
-        else if (get<ErrorType>(t))
-        {
-            // ~error is still an error, so intersecting with the negation is the same as intersecting with a type
-            TypeId errors = here.errors;
-            clearNormal(here);
-            here.errors = get<ErrorType>(errors) ? errors : t;
-        }
         else if (auto nt = get<NegationType>(t))
         {
+            if (FFlag::LuauNormalizeNegationFix)
                 here.tyvars = std::move(tyvars);
+
             return intersectNormalWithTy(here, nt->ty, seenTablePropPairs, seenSetTypes);
         }
         else
@@ -3334,7 +3323,7 @@ NormalizationResult Normalizer::intersectNormalWithTy(
     }
     else if (get<NeverType>(there))
     {
-        here.externTypes.resetToNever();
+        here.classes.resetToNever();
     }
     else if (get<NoRefineType>(there))
     {
@@ -3352,43 +3341,19 @@ NormalizationResult Normalizer::intersectNormalWithTy(
     return NormalizationResult::True;
 }
 
-void makeTableShared_DEPRECATED(TypeId ty)
-{
-    ty = follow(ty);
-    if (auto tableTy = getMutable<TableType>(ty))
-    {
-        for (auto& [_, prop] : tableTy->props)
-            prop.makeShared();
-    }
-    else if (auto metatableTy = get<MetatableType>(ty))
-    {
-        makeTableShared_DEPRECATED(metatableTy->metatable);
-        makeTableShared_DEPRECATED(metatableTy->table);
-    }
-}
-
-void makeTableShared(TypeId ty, DenseHashSet<TypeId>& seen)
-{
-    ty = follow(ty);
-    if (seen.contains(ty))
-        return;
-    seen.insert(ty);
-    if (auto tableTy = getMutable<TableType>(ty))
-    {
-        for (auto& [_, prop] : tableTy->props)
-            prop.makeShared();
-    }
-    else if (auto metatableTy = get<MetatableType>(ty))
-    {
-        makeTableShared(metatableTy->metatable, seen);
-        makeTableShared(metatableTy->table, seen);
-    }
-}
-
 void makeTableShared(TypeId ty)
 {
-    DenseHashSet<TypeId> seen{nullptr};
+    ty = follow(ty);
-    makeTableShared(ty, seen);
+    if (auto tableTy = getMutable<TableType>(ty))
+    {
+        for (auto& [_, prop] : tableTy->props)
+            prop.makeShared();
+    }
+    else if (auto metatableTy = get<MetatableType>(ty))
+    {
+        makeTableShared(metatableTy->metatable);
+        makeTableShared(metatableTy->table);
+    }
 }
 
 // -------- Convert back from a normalized type to a type
@@ -3403,18 +3368,18 @@ TypeId Normalizer::typeFromNormal(const NormalizedType& norm)
     if (!get<NeverType>(norm.booleans))
         result.push_back(norm.booleans);
 
-    if (isTop(builtinTypes, norm.externTypes))
+    if (isTop(builtinTypes, norm.classes))
     {
-        result.push_back(builtinTypes->externType);
+        result.push_back(builtinTypes->classType);
     }
-    else if (!norm.externTypes.isNever())
+    else if (!norm.classes.isNever())
     {
         std::vector<TypeId> parts;
-        parts.reserve(norm.externTypes.externTypes.size());
+        parts.reserve(norm.classes.classes.size());
 
-        for (const TypeId normTy : norm.externTypes.ordering)
+        for (const TypeId normTy : norm.classes.ordering)
         {
-            const TypeIds& normNegations = norm.externTypes.externTypes.at(normTy);
+            const TypeIds& normNegations = norm.classes.classes.at(normTy);
 
             if (normNegations.empty())
             {
@@ -3490,10 +3455,7 @@ TypeId Normalizer::typeFromNormal(const NormalizedType& norm)
         result.reserve(result.size() + norm.tables.size());
         for (auto table : norm.tables)
         {
-            if (FFlag::LuauNormalizationCatchMetatableCycles)
             makeTableShared(table);
-            else
-                makeTableShared_DEPRECATED(table);
             result.push_back(table);
         }
     }

Analysis/src/OverloadResolution.cpp

@@ -10,8 +10,6 @@
 #include "Luau/TypeUtils.h"
 #include "Luau/Unifier2.h"
 
-LUAU_FASTFLAGVARIABLE(LuauArityMismatchOnUndersaturatedUnknownArguments)
-
 namespace Luau
 {
 
@@ -256,24 +254,8 @@ std::pair<OverloadResolver::Analysis, ErrorVec> OverloadResolver::checkOverload_
             }
 
             // If any of the unsatisfied arguments are not supertypes of
-            // nil or are `unknown`, then this overload does not match.
+            // nil, then this overload does not match.
             for (size_t i = firstUnsatisfiedArgument; i < requiredHead.size(); ++i)
-            {
-                if (FFlag::LuauArityMismatchOnUndersaturatedUnknownArguments)
-                {
-                    if (get<UnknownType>(follow(requiredHead[i])) || !subtyping.isSubtype(builtinTypes->nilType, requiredHead[i], scope).isSubtype)
-                    {
-                        auto [minParams, optMaxParams] = getParameterExtents(TxnLog::empty(), fn->argTypes);
-                        for (auto arg : fn->argTypes)
-                            if (get<UnknownType>(follow(arg)))
-                                minParams += 1;
-
-                        TypeError error{fnExpr->location, CountMismatch{minParams, optMaxParams, args->head.size(), CountMismatch::Arg, isVariadic}};
-
-                        return {Analysis::ArityMismatch, {error}};
-                    }
-                }
-                else
             {
                 if (!subtyping.isSubtype(builtinTypes->nilType, requiredHead[i], scope).isSubtype)
                 {
@@ -283,7 +265,6 @@ std::pair<OverloadResolver::Analysis, ErrorVec> OverloadResolver::checkOverload_
                     return {Analysis::ArityMismatch, {error}};
                 }
             }
-            }
 
             return {Analysis::Ok, {}};
         }
@@ -473,7 +454,7 @@ SolveResult solveFunctionCall(
 
     TypePackId resultPack = arena->freshTypePack(scope);
 
-    TypeId inferredTy = arena->addType(FunctionType{TypeLevel{}, argsPack, resultPack});
+    TypeId inferredTy = arena->addType(FunctionType{TypeLevel{}, scope.get(), argsPack, resultPack});
     Unifier2 u2{NotNull{arena}, builtinTypes, scope, iceReporter};
 
     const bool occursCheckPassed = u2.unify(*overloadToUse, inferredTy);

Analysis/src/RequireTracer.cpp

@@ -4,8 +4,6 @@
 #include "Luau/Ast.h"
 #include "Luau/Module.h"
 
-LUAU_FASTFLAG(LuauStoreReturnTypesAsPackOnAst)
-
 namespace Luau
 {
 
@@ -67,12 +65,6 @@ struct RequireTracer : AstVisitor
         return true;
     }
 
-    bool visit(AstTypePack* node) override
-    {
-        // allow resolving require inside `typeof` annotations
-        return FFlag::LuauStoreReturnTypesAsPackOnAst;
-    }
-
     AstExpr* getDependent_DEPRECATED(AstExpr* node)
     {
         if (AstExprLocal* expr = node->as<AstExprLocal>())

Analysis/src/Simplify.cpp

@@ -6,7 +6,6 @@
 #include "Luau/DenseHash.h"
 #include "Luau/RecursionCounter.h"
 #include "Luau/Set.h"
-#include "Luau/Type.h"
 #include "Luau/TypeArena.h"
 #include "Luau/TypePairHash.h"
 #include "Luau/TypeUtils.h"
@@ -15,10 +14,8 @@
 
 LUAU_FASTINT(LuauTypeReductionRecursionLimit)
 LUAU_FASTFLAG(LuauSolverV2)
-LUAU_DYNAMIC_FASTINTVARIABLE(LuauSimplificationComplexityLimit, 8)
+LUAU_DYNAMIC_FASTINTVARIABLE(LuauSimplificationComplexityLimit, 8);
-LUAU_FASTFLAGVARIABLE(LuauSimplificationRecheckAssumption)
+LUAU_FASTFLAGVARIABLE(LuauFlagBasicIntersectFollows);
-LUAU_FASTFLAGVARIABLE(LuauOptimizeFalsyAndTruthyIntersect)
-LUAU_FASTFLAGVARIABLE(LuauSimplificationTableExternType)
 
 namespace Luau
 {
@@ -50,8 +47,6 @@ struct TypeSimplifier
     // Attempt to intersect the two types.  Does not recurse.  Does not handle
     // unions, intersections, or negations.
     std::optional<TypeId> basicIntersect(TypeId left, TypeId right);
-    std::optional<TypeId> basicIntersectWithTruthy(TypeId target) const;
-    std::optional<TypeId> basicIntersectWithFalsy(TypeId target) const;
 
     TypeId intersect(TypeId left, TypeId right);
     TypeId union_(TypeId left, TypeId right);
@@ -318,13 +313,11 @@ Relation relate(TypeId left, TypeId right, SimplifierSeenSet& seen)
     {
         if (get<AnyType>(right))
             return Relation::Subset;
-
+        else if (get<UnknownType>(right))
-        if (get<UnknownType>(right))
             return Relation::Coincident;
-
+        else if (get<ErrorType>(right))
-        if (get<ErrorType>(right))
             return Relation::Disjoint;
-
+        else
             return Relation::Superset;
     }
 
@@ -335,7 +328,7 @@ Relation relate(TypeId left, TypeId right, SimplifierSeenSet& seen)
     {
         if (get<AnyType>(right))
             return Relation::Coincident;
-
+        else
             return Relation::Superset;
     }
 
@@ -360,7 +353,7 @@ Relation relate(TypeId left, TypeId right, SimplifierSeenSet& seen)
     // * FunctionType
     // * TableType
     // * MetatableType
-    // * ExternType
+    // * ClassType
     // * UnionType
     // * IntersectionType
     // * NegationType
@@ -368,33 +361,26 @@ Relation relate(TypeId left, TypeId right, SimplifierSeenSet& seen)
     if (isTypeVariable(left) || isTypeVariable(right))
         return Relation::Intersects;
 
-    if (FFlag::LuauSimplificationTableExternType)
-    {
-        // if either type is a type function, we cannot know if they'll be related.
-        if (get<TypeFunctionInstanceType>(left) || get<TypeFunctionInstanceType>(right))
-            return Relation::Intersects;
-    }
-
     if (get<ErrorType>(left))
     {
         if (get<ErrorType>(right))
             return Relation::Coincident;
         else if (get<AnyType>(right))
             return Relation::Subset;
-
+        else
             return Relation::Disjoint;
     }
-    else if (get<ErrorType>(right))
+    if (get<ErrorType>(right))
         return flip(relate(right, left, seen));
 
     if (get<NeverType>(left))
     {
         if (get<NeverType>(right))
             return Relation::Coincident;
-
+        else
             return Relation::Subset;
     }
-    else if (get<NeverType>(right))
+    if (get<NeverType>(right))
         return flip(relate(right, left, seen));
 
     if (auto ut = get<IntersectionType>(left))
@@ -458,7 +444,7 @@ Relation relate(TypeId left, TypeId right, SimplifierSeenSet& seen)
         {
             if (lp->type == rp->type)
                 return Relation::Coincident;
-
+            else
                 return Relation::Disjoint;
         }
 
@@ -466,10 +452,9 @@ Relation relate(TypeId left, TypeId right, SimplifierSeenSet& seen)
         {
             if (lp->type == PrimitiveType::String && rs->variant.get_if<StringSingleton>())
                 return Relation::Superset;
-
+            else if (lp->type == PrimitiveType::Boolean && rs->variant.get_if<BooleanSingleton>())
-            if (lp->type == PrimitiveType::Boolean && rs->variant.get_if<BooleanSingleton>())
                 return Relation::Superset;
-
+            else
                 return Relation::Disjoint;
         }
 
@@ -477,34 +462,33 @@ Relation relate(TypeId left, TypeId right, SimplifierSeenSet& seen)
         {
             if (get<FunctionType>(right))
                 return Relation::Superset;
-
+            else
                 return Relation::Disjoint;
         }
         if (lp->type == PrimitiveType::Table)
         {
             if (get<TableType>(right))
                 return Relation::Superset;
-
+            else
                 return Relation::Disjoint;
         }
 
-        if (get<FunctionType>(right) || get<TableType>(right) || get<MetatableType>(right) || get<ExternType>(right))
+        if (get<FunctionType>(right) || get<TableType>(right) || get<MetatableType>(right) || get<ClassType>(right))
             return Relation::Disjoint;
     }
 
     if (auto ls = get<SingletonType>(left))
     {
-        if (get<FunctionType>(right) || get<TableType>(right) || get<MetatableType>(right) || get<ExternType>(right))
+        if (get<FunctionType>(right) || get<TableType>(right) || get<MetatableType>(right) || get<ClassType>(right))
             return Relation::Disjoint;
 
         if (get<PrimitiveType>(right))
             return flip(relate(right, left, seen));
-
         if (auto rs = get<SingletonType>(right))
         {
             if (ls->variant == rs->variant)
                 return Relation::Coincident;
-
+            else
                 return Relation::Disjoint;
         }
     }
@@ -515,10 +499,10 @@ Relation relate(TypeId left, TypeId right, SimplifierSeenSet& seen)
         {
             if (rp->type == PrimitiveType::Function)
                 return Relation::Subset;
-
+            else
                 return Relation::Disjoint;
         }
-
+        else
             return Relation::Intersects;
     }
 
@@ -528,11 +512,10 @@ Relation relate(TypeId left, TypeId right, SimplifierSeenSet& seen)
         {
             if (rp->type == PrimitiveType::Table)
                 return Relation::Subset;
-
+            else
                 return Relation::Disjoint;
         }
-
+        else if (auto rt = get<TableType>(right))
-        if (auto rt = get<TableType>(right))
         {
             // TODO PROBABLY indexers and metatables.
             if (1 == rt->props.size())
@@ -552,57 +535,28 @@ Relation relate(TypeId left, TypeId right, SimplifierSeenSet& seen)
                  */
                 if (lt->props.size() > 1 && r == Relation::Superset)
                     return Relation::Intersects;
-
+                else
                     return r;
             }
-
+            else if (1 == lt->props.size())
-            if (1 == lt->props.size())
                 return flip(relate(right, left, seen));
-
+            else
                 return Relation::Intersects;
         }
-
-        if (FFlag::LuauSimplificationTableExternType)
-        {
-            if (auto re = get<ExternType>(right))
-            {
-                Relation overall = Relation::Coincident;
-
-                for (auto& [name, prop] : lt->props)
-                {
-                    if (auto propInExternType = re->props.find(name); propInExternType != re->props.end())
-                    {
-                        Relation propRel = relate(prop.type(), propInExternType->second.type());
-
-                        if (propRel == Relation::Disjoint)
-                            return Relation::Disjoint;
-
-                        if (propRel == Relation::Coincident)
-                            continue;
-
-                        overall = Relation::Intersects;
-                    }
-                }
-
-                return overall;
-            }
-        }
-
         // TODO metatables
 
         return Relation::Disjoint;
     }
 
-    if (auto ct = get<ExternType>(left))
+    if (auto ct = get<ClassType>(left))
     {
-        if (auto rct = get<ExternType>(right))
+        if (auto rct = get<ClassType>(right))
         {
             if (isSubclass(ct, rct))
                 return Relation::Subset;
-
+            else if (isSubclass(rct, ct))
-            if (isSubclass(rct, ct))
                 return Relation::Superset;
-
+            else
                 return Relation::Disjoint;
         }
 
@@ -753,9 +707,7 @@ TypeId TypeSimplifier::intersectUnionWithType(TypeId left, TypeId right)
     bool changed = false;
     std::set<TypeId> newParts;
 
-    size_t maxSize = DFInt::LuauSimplificationComplexityLimit;
+    if (leftUnion->options.size() > (size_t)DFInt::LuauSimplificationComplexityLimit)
-
-    if (leftUnion->options.size() > maxSize)
         return arena->addType(IntersectionType{{left, right}});
 
     for (TypeId part : leftUnion)
@@ -770,13 +722,6 @@ TypeId TypeSimplifier::intersectUnionWithType(TypeId left, TypeId right)
         }
 
         newParts.insert(simplified);
-
-        if (FFlag::LuauSimplificationRecheckAssumption)
-        {
-            // Initial combination size check could not predict nested union iteration
-            if (newParts.size() > maxSize)
-                return arena->addType(IntersectionType{{left, right}});
-        }
     }
 
     if (!changed)
@@ -817,13 +762,6 @@ TypeId TypeSimplifier::intersectUnions(TypeId left, TypeId right)
                 continue;
 
             newParts.insert(simplified);
-
-            if (FFlag::LuauSimplificationRecheckAssumption)
-            {
-                // Initial combination size check could not predict nested union iteration
-                if (newParts.size() > maxSize)
-                    return arena->addType(IntersectionType{{left, right}});
-            }
         }
     }
 
@@ -902,78 +840,6 @@ TypeId TypeSimplifier::intersectNegatedUnion(TypeId left, TypeId right)
         return intersectFromParts(std::move(newParts));
 }
 
-std::optional<TypeId> TypeSimplifier::basicIntersectWithTruthy(TypeId target) const
-{
-    target = follow(target);
-
-    if (is<UnknownType>(target))
-        return builtinTypes->truthyType;
-
-    if (is<AnyType>(target))
-        // any = *error-type* | unknown, so truthy & any = *error-type* | truthy
-        return arena->addType(UnionType{{builtinTypes->truthyType, builtinTypes->errorType}});
-
-    if (is<NeverType, ErrorType>(target))
-        return target;
-
-    if (is<FunctionType, TableType, MetatableType, ExternType>(target))
-        return target;
-
-    if (auto pt = get<PrimitiveType>(target))
-    {
-        switch (pt->type)
-        {
-        case PrimitiveType::NilType:
-            return builtinTypes->neverType;
-        case PrimitiveType::Boolean:
-            return builtinTypes->trueType;
-        default:
-            return target;
-        }
-    }
-
-    if (auto st = get<SingletonType>(target))
-        return st->variant == BooleanSingleton{false} ? builtinTypes->neverType : target;
-
-    return std::nullopt;
-}
-
-std::optional<TypeId> TypeSimplifier::basicIntersectWithFalsy(TypeId target) const
-{
-    target = follow(target);
-
-    if (is<NeverType, ErrorType>(target))
-        return target;
-
-    if (is<AnyType>(target))
-        // any = *error-type* | unknown, so falsy & any = *error-type* | falsy
-        return arena->addType(UnionType{{builtinTypes->falsyType, builtinTypes->errorType}});
-
-    if (is<UnknownType>(target))
-        return builtinTypes->falsyType;
-
-    if (is<FunctionType, TableType, MetatableType, ExternType>(target))
-        return builtinTypes->neverType;
-
-    if (auto pt = get<PrimitiveType>(target))
-    {
-        switch (pt->type)
-        {
-        case PrimitiveType::NilType:
-            return builtinTypes->nilType;
-        case PrimitiveType::Boolean:
-            return builtinTypes->falseType;
-        default:
-            return builtinTypes->neverType;
-        }
-    }
-
-    if (auto st = get<SingletonType>(target))
-        return st->variant == BooleanSingleton{false} ? builtinTypes->falseType : builtinTypes->neverType;
-
-    return std::nullopt;
-}
-
 TypeId TypeSimplifier::intersectTypeWithNegation(TypeId left, TypeId right)
 {
     const NegationType* leftNegation = get<NegationType>(left);
@@ -1200,8 +1066,11 @@ TypeId TypeSimplifier::intersectIntersectionWithType(TypeId left, TypeId right)
 
 std::optional<TypeId> TypeSimplifier::basicIntersect(TypeId left, TypeId right)
 {
+    if (FFlag::LuauFlagBasicIntersectFollows)
+    {
         left = follow(left);
         right = follow(right);
+    }
 
     if (get<AnyType>(left) && get<ErrorType>(right))
         return right;
@@ -1310,25 +1179,6 @@ std::optional<TypeId> TypeSimplifier::basicIntersect(TypeId left, TypeId right)
         return std::nullopt;
     }
 
-    if (FFlag::LuauOptimizeFalsyAndTruthyIntersect)
-    {
-        if (isTruthyType(left))
-            if (auto res = basicIntersectWithTruthy(right))
-                return res;
-
-        if (isTruthyType(right))
-            if (auto res = basicIntersectWithTruthy(left))
-                return res;
-
-        if (isFalsyType(left))
-            if (auto res = basicIntersectWithFalsy(right))
-                return res;
-
-        if (isFalsyType(right))
-            if (auto res = basicIntersectWithFalsy(left))
-                return res;
-    }
-
     Relation relation = relate(left, right);
     if (left == right || Relation::Coincident == relation)
         return left;

Analysis/src/Substitution.cpp

@@ -2,23 +2,24 @@
 #include "Luau/Substitution.h"
 
 #include "Luau/Common.h"
+#include "Luau/Clone.h"
 #include "Luau/TxnLog.h"
 #include "Luau/Type.h"
 
 #include <algorithm>
+#include <stdexcept>
 
 LUAU_FASTINTVARIABLE(LuauTarjanChildLimit, 10000)
 LUAU_FASTFLAG(LuauSolverV2)
 LUAU_FASTINTVARIABLE(LuauTarjanPreallocationSize, 256)
 LUAU_FASTFLAG(LuauSyntheticErrors)
-LUAU_FASTFLAG(LuauDeprecatedAttribute)
 
 namespace Luau
 {
 
-static TypeId shallowClone(TypeId ty, TypeArena& dest, const TxnLog* log)
+static TypeId shallowClone(TypeId ty, TypeArena& dest, const TxnLog* log, bool alwaysClone)
 {
-    auto go = [ty, &dest](auto&& a)
+    auto go = [ty, &dest, alwaysClone](auto&& a)
     {
         using T = std::decay_t<decltype(a)>;
 
@@ -94,15 +95,13 @@ static TypeId shallowClone(TypeId ty, TypeArena& dest, const TxnLog* log)
             return dest.addType(a);
         else if constexpr (std::is_same_v<T, FunctionType>)
         {
-            FunctionType clone = FunctionType{a.level, a.argTypes, a.retTypes, a.definition, a.hasSelf};
+            FunctionType clone = FunctionType{a.level, a.scope, a.argTypes, a.retTypes, a.definition, a.hasSelf};
             clone.generics = a.generics;
             clone.genericPacks = a.genericPacks;
             clone.magic = a.magic;
             clone.tags = a.tags;
             clone.argNames = a.argNames;
             clone.isCheckedFunction = a.isCheckedFunction;
-            if (FFlag::LuauDeprecatedAttribute)
-                clone.isDeprecatedFunction = a.isDeprecatedFunction;
             return dest.addType(std::move(clone));
         }
         else if constexpr (std::is_same_v<T, TableType>)
@@ -136,11 +135,16 @@ static TypeId shallowClone(TypeId ty, TypeArena& dest, const TxnLog* log)
             clone.parts = a.parts;
             return dest.addType(std::move(clone));
         }
-        else if constexpr (std::is_same_v<T, ExternType>)
+        else if constexpr (std::is_same_v<T, ClassType>)
         {
-            ExternType clone{a.name, a.props, a.parent, a.metatable, a.tags, a.userData, a.definitionModuleName, a.definitionLocation, a.indexer};
+            if (alwaysClone)
+            {
+                ClassType clone{a.name, a.props, a.parent, a.metatable, a.tags, a.userData, a.definitionModuleName, a.definitionLocation, a.indexer};
                 return dest.addType(std::move(clone));
             }
+            else
+                return ty;
+        }
         else if constexpr (std::is_same_v<T, NegationType>)
             return dest.addType(NegationType{a.ty});
         else if constexpr (std::is_same_v<T, TypeFunctionInstanceType>)
@@ -252,21 +256,21 @@ void Tarjan::visitChildren(TypeId ty, int index)
         for (TypePackId a : tfit->packArguments)
             visitChild(a);
     }
-    else if (const ExternType* etv = get<ExternType>(ty))
+    else if (const ClassType* ctv = get<ClassType>(ty))
     {
-        for (const auto& [name, prop] : etv->props)
+        for (const auto& [name, prop] : ctv->props)
             visitChild(prop.type());
 
-        if (etv->parent)
+        if (ctv->parent)
-            visitChild(*etv->parent);
+            visitChild(*ctv->parent);
 
-        if (etv->metatable)
+        if (ctv->metatable)
-            visitChild(*etv->metatable);
+            visitChild(*ctv->metatable);
 
-        if (etv->indexer)
+        if (ctv->indexer)
         {
-            visitChild(etv->indexer->indexType);
+            visitChild(ctv->indexer->indexType);
-            visitChild(etv->indexer->indexResultType);
+            visitChild(ctv->indexer->indexResultType);
         }
     }
     else if (const NegationType* ntv = get<NegationType>(ty))
@@ -540,27 +544,6 @@ void Tarjan::visitSCC(int index)
     }
 }
 
-bool Tarjan::ignoreChildren(TypeId ty)
-{
-    return false;
-}
-
-bool Tarjan::ignoreChildren(TypePackId ty)
-{
-    return false;
-}
-
-// Some subclasses might ignore children visit, but not other actions like replacing the children
-bool Tarjan::ignoreChildrenVisit(TypeId ty)
-{
-    return ignoreChildren(ty);
-}
-
-bool Tarjan::ignoreChildrenVisit(TypePackId ty)
-{
-    return ignoreChildren(ty);
-}
-
 TarjanResult Tarjan::findDirty(TypeId ty)
 {
     return visitRoot(ty);
@@ -571,11 +554,6 @@ TarjanResult Tarjan::findDirty(TypePackId tp)
     return visitRoot(tp);
 }
 
-Substitution::Substitution(TypeArena* arena)
-    : Substitution(TxnLog::empty(), arena)
-{
-}
-
 Substitution::Substitution(const TxnLog* log_, TypeArena* arena)
     : arena(arena)
 {
@@ -676,7 +654,7 @@ void Substitution::resetState(const TxnLog* log, TypeArena* arena)
 
 TypeId Substitution::clone(TypeId ty)
 {
-    return shallowClone(ty, *arena, log);
+    return shallowClone(ty, *arena, log, /* alwaysClone */ true);
 }
 
 TypePackId Substitution::clone(TypePackId tp)
@@ -838,21 +816,21 @@ void Substitution::replaceChildren(TypeId ty)
         for (TypePackId& a : tfit->packArguments)
             a = replace(a);
     }
-    else if (ExternType* etv = getMutable<ExternType>(ty))
+    else if (ClassType* ctv = getMutable<ClassType>(ty))
     {
-        for (auto& [name, prop] : etv->props)
+        for (auto& [name, prop] : ctv->props)
             prop.setType(replace(prop.type()));
 
-        if (etv->parent)
+        if (ctv->parent)
-            etv->parent = replace(*etv->parent);
+            ctv->parent = replace(*ctv->parent);
 
-        if (etv->metatable)
+        if (ctv->metatable)
-            etv->metatable = replace(*etv->metatable);
+            ctv->metatable = replace(*ctv->metatable);
 
-        if (etv->indexer)
+        if (ctv->indexer)
         {
-            etv->indexer->indexType = replace(etv->indexer->indexType);
+            ctv->indexer->indexType = replace(ctv->indexer->indexType);
-            etv->indexer->indexResultType = replace(etv->indexer->indexResultType);
+            ctv->indexer->indexResultType = replace(ctv->indexer->indexResultType);
         }
     }
     else if (NegationType* ntv = getMutable<NegationType>(ty))
@@ -892,13 +870,4 @@ void Substitution::replaceChildren(TypePackId tp)
     }
 }
 
-template<typename Ty>
-std::optional<Ty> Substitution::replace(std::optional<Ty> ty)
-{
-    if (ty)
-        return replace(*ty);
-    else
-        return std::nullopt;
-}
-
 } // namespace Luau

Analysis/src/Subtyping.cpp

@@ -7,11 +7,13 @@
 #include "Luau/Normalize.h"
 #include "Luau/RecursionCounter.h"
 #include "Luau/Scope.h"
+#include "Luau/StringUtils.h"
 #include "Luau/Substitution.h"
 #include "Luau/ToString.h"
 #include "Luau/TxnLog.h"
 #include "Luau/Type.h"
 #include "Luau/TypeArena.h"
+#include "Luau/TypeCheckLimits.h"
 #include "Luau/TypeFunction.h"
 #include "Luau/TypePack.h"
 #include "Luau/TypePath.h"
@@ -20,8 +22,6 @@
 #include <algorithm>
 
 LUAU_FASTFLAGVARIABLE(DebugLuauSubtypingCheckPathValidity)
-LUAU_FASTINTVARIABLE(LuauSubtypingReasoningLimit, 100)
-LUAU_FASTFLAGVARIABLE(LuauSubtypingEnableReasoningLimit)
 
 namespace Luau
 {
@@ -31,7 +31,7 @@ struct VarianceFlipper
     Subtyping::Variance* variance;
     Subtyping::Variance oldValue;
 
-    explicit VarianceFlipper(Subtyping::Variance* v)
+    VarianceFlipper(Subtyping::Variance* v)
         : variance(v)
         , oldValue(*v)
     {
@@ -99,9 +99,6 @@ static SubtypingReasonings mergeReasonings(const SubtypingReasonings& a, const S
             else
                 result.insert(r);
         }
-
-        if (FFlag::LuauSubtypingEnableReasoningLimit && result.size() >= size_t(FInt::LuauSubtypingReasoningLimit))
-            return result;
     }
 
     for (const SubtypingReasoning& r : b)
@@ -118,9 +115,6 @@ static SubtypingReasonings mergeReasonings(const SubtypingReasonings& a, const S
             else
                 result.insert(r);
         }
-
-        if (FFlag::LuauSubtypingEnableReasoningLimit && result.size() >= size_t(FInt::LuauSubtypingReasoningLimit))
-            return result;
     }
 
     return result;
@@ -313,7 +307,7 @@ struct ApplyMappedGenerics : Substitution
 
     bool ignoreChildren(TypeId ty) override
     {
-        if (get<ExternType>(ty))
+        if (get<ClassType>(ty))
             return true;
 
         return ty->persistent;
@@ -421,14 +415,6 @@ SubtypingResult Subtyping::isSubtype(TypeId subTy, TypeId superTy, NotNull<Scope
 
     SubtypingResult result = isCovariantWith(env, subTy, superTy, scope);
 
-    if (result.normalizationTooComplex)
-    {
-        if (result.isCacheable)
-            resultCache[{subTy, superTy}] = result;
-
-        return result;
-    }
-
     for (const auto& [subTy, bounds] : env.mappedGenerics)
     {
         const auto& lb = bounds.lowerBound;
@@ -606,12 +592,7 @@ SubtypingResult Subtyping::isCovariantWith(SubtypingEnvironment& env, TypeId sub
         if (!result.isSubtype && !result.normalizationTooComplex)
         {
             SubtypingResult semantic = isCovariantWith(env, normalizer->normalize(subTy), normalizer->normalize(superTy), scope);
-
+            if (semantic.isSubtype)
-            if (semantic.normalizationTooComplex)
-            {
-                result = semantic;
-            }
-            else if (semantic.isSubtype)
             {
                 semantic.reasoning.clear();
                 result = semantic;
@@ -626,12 +607,7 @@ SubtypingResult Subtyping::isCovariantWith(SubtypingEnvironment& env, TypeId sub
         if (!result.isSubtype && !result.normalizationTooComplex)
         {
             SubtypingResult semantic = isCovariantWith(env, normalizer->normalize(subTy), normalizer->normalize(superTy), scope);
-
+            if (semantic.isSubtype)
-            if (semantic.normalizationTooComplex)
-            {
-                result = semantic;
-            }
-            else if (semantic.isSubtype)
             {
                 // Clear the semantic reasoning, as any reasonings within
                 // potentially contain invalid paths.
@@ -742,9 +718,9 @@ SubtypingResult Subtyping::isCovariantWith(SubtypingEnvironment& env, TypeId sub
         result = isCovariantWith(env, p, scope);
     else if (auto p = get2<MetatableType, TableType>(subTy, superTy))
         result = isCovariantWith(env, p, scope);
-    else if (auto p = get2<ExternType, ExternType>(subTy, superTy))
+    else if (auto p = get2<ClassType, ClassType>(subTy, superTy))
         result = isCovariantWith(env, p, scope);
-    else if (auto p = get2<ExternType, TableType>(subTy, superTy))
+    else if (auto p = get2<ClassType, TableType>(subTy, superTy))
         result = isCovariantWith(env, subTy, p.first, superTy, p.second, scope);
     else if (auto p = get2<TableType, PrimitiveType>(subTy, superTy))
         result = isCovariantWith(env, p, scope);
@@ -1106,10 +1082,6 @@ SubtypingResult Subtyping::isCovariantWith(SubtypingEnvironment& env, TypeId sub
     for (TypeId ty : superUnion)
     {
         SubtypingResult next = isCovariantWith(env, subTy, ty, scope);
-
-        if (next.normalizationTooComplex)
-            return SubtypingResult{false, /* normalizationTooComplex */ true};
-
         if (next.isSubtype)
             return SubtypingResult{true};
     }
@@ -1128,13 +1100,7 @@ SubtypingResult Subtyping::isCovariantWith(SubtypingEnvironment& env, const Unio
     std::vector<SubtypingResult> subtypings;
     size_t i = 0;
     for (TypeId ty : subUnion)
-    {
         subtypings.push_back(isCovariantWith(env, ty, superTy, scope).withSubComponent(TypePath::Index{i++, TypePath::Index::Variant::Union}));
-
-        if (subtypings.back().normalizationTooComplex)
-            return SubtypingResult{false, /* normalizationTooComplex */ true};
-    }
-
     return SubtypingResult::all(subtypings);
 }
 
@@ -1144,13 +1110,7 @@ SubtypingResult Subtyping::isCovariantWith(SubtypingEnvironment& env, TypeId sub
     std::vector<SubtypingResult> subtypings;
     size_t i = 0;
     for (TypeId ty : superIntersection)
-    {
         subtypings.push_back(isCovariantWith(env, subTy, ty, scope).withSuperComponent(TypePath::Index{i++, TypePath::Index::Variant::Intersection}));
-
-        if (subtypings.back().normalizationTooComplex)
-            return SubtypingResult{false, /* normalizationTooComplex */ true};
-    }
-
     return SubtypingResult::all(subtypings);
 }
 
@@ -1160,13 +1120,7 @@ SubtypingResult Subtyping::isCovariantWith(SubtypingEnvironment& env, const Inte
     std::vector<SubtypingResult> subtypings;
     size_t i = 0;
     for (TypeId ty : subIntersection)
-    {
         subtypings.push_back(isCovariantWith(env, ty, superTy, scope).withSubComponent(TypePath::Index{i++, TypePath::Index::Variant::Intersection}));
-
-        if (subtypings.back().normalizationTooComplex)
-            return SubtypingResult{false, /* normalizationTooComplex */ true};
-    }
-
     return SubtypingResult::any(subtypings);
 }
 
@@ -1334,7 +1288,7 @@ SubtypingResult Subtyping::isCovariantWith(SubtypingEnvironment& env, const Type
     }
     // the top class type is not actually a primitive type, so the negation of
     // any one of them includes the top class type.
-    else if (auto p = get2<ExternType, PrimitiveType>(subTy, negatedTy))
+    else if (auto p = get2<ClassType, PrimitiveType>(subTy, negatedTy))
         result = {true};
     else if (auto p = get<PrimitiveType>(negatedTy); p && is<TableType, MetatableType>(subTy))
         result = {p->type != PrimitiveType::Table};
@@ -1342,9 +1296,9 @@ SubtypingResult Subtyping::isCovariantWith(SubtypingEnvironment& env, const Type
         result = {p.second->type != PrimitiveType::Function};
     else if (auto p = get2<SingletonType, SingletonType>(subTy, negatedTy))
         result = {*p.first != *p.second};
-    else if (auto p = get2<ExternType, ExternType>(subTy, negatedTy))
+    else if (auto p = get2<ClassType, ClassType>(subTy, negatedTy))
         result = SubtypingResult::negate(isCovariantWith(env, p.first, p.second, scope));
-    else if (get2<FunctionType, ExternType>(subTy, negatedTy))
+    else if (get2<FunctionType, ClassType>(subTy, negatedTy))
         result = {true};
     else if (is<ErrorType, FunctionType, TableType, MetatableType>(negatedTy))
         iceReporter->ice("attempting to negate a non-testable type");
@@ -1456,7 +1410,7 @@ SubtypingResult Subtyping::isCovariantWith(SubtypingEnvironment& env, const Meta
         // of the supertype table.
         //
         // There's a flaw here in that if the __index metamethod contributes a new
-        // field that would satisfy the subtyping relationship, we'll erroneously say
+        // field that would satisfy the subtyping relationship, we'll erronously say
         // that the metatable isn't a subtype of the table, even though they have
         // compatible properties/shapes. We'll revisit this later when we have a
         // better understanding of how important this is.
@@ -1469,15 +1423,15 @@ SubtypingResult Subtyping::isCovariantWith(SubtypingEnvironment& env, const Meta
     }
 }
 
-SubtypingResult Subtyping::isCovariantWith(SubtypingEnvironment& env, const ExternType* subExternType, const ExternType* superExternType, NotNull<Scope> scope)
+SubtypingResult Subtyping::isCovariantWith(SubtypingEnvironment& env, const ClassType* subClass, const ClassType* superClass, NotNull<Scope> scope)
 {
-    return {isSubclass(subExternType, superExternType)};
+    return {isSubclass(subClass, superClass)};
 }
 
 SubtypingResult Subtyping::isCovariantWith(
     SubtypingEnvironment& env,
     TypeId subTy,
-    const ExternType* subExternType,
+    const ClassType* subClass,
     TypeId superTy,
     const TableType* superTable,
     NotNull<Scope> scope
@@ -1489,7 +1443,7 @@ SubtypingResult Subtyping::isCovariantWith(
 
     for (const auto& [name, prop] : superTable->props)
     {
-        if (auto classProp = lookupExternTypeProp(subExternType, name))
+        if (auto classProp = lookupClassProp(subClass, name))
         {
             result.andAlso(isCovariantWith(env, *classProp, prop, name, scope));
         }
@@ -1659,7 +1613,7 @@ SubtypingResult Subtyping::isCovariantWith(
     SubtypingResult result = isCovariantWith(env, subNorm->tops, superNorm->tops, scope);
     result.andAlso(isCovariantWith(env, subNorm->booleans, superNorm->booleans, scope));
     result.andAlso(
-        isCovariantWith(env, subNorm->externTypes, superNorm->externTypes, scope).orElse(isCovariantWith(env, subNorm->externTypes, superNorm->tables, scope))
+        isCovariantWith(env, subNorm->classes, superNorm->classes, scope).orElse(isCovariantWith(env, subNorm->classes, superNorm->tables, scope))
     );
     result.andAlso(isCovariantWith(env, subNorm->errors, superNorm->errors, scope));
     result.andAlso(isCovariantWith(env, subNorm->nils, superNorm->nils, scope));
@@ -1676,24 +1630,24 @@ SubtypingResult Subtyping::isCovariantWith(
 
 SubtypingResult Subtyping::isCovariantWith(
     SubtypingEnvironment& env,
-    const NormalizedExternType& subExternType,
+    const NormalizedClassType& subClass,
-    const NormalizedExternType& superExternType,
+    const NormalizedClassType& superClass,
     NotNull<Scope> scope
 )
 {
-    for (const auto& [subExternTypeTy, _] : subExternType.externTypes)
+    for (const auto& [subClassTy, _] : subClass.classes)
     {
         SubtypingResult result;
 
-        for (const auto& [superExternTypeTy, superNegations] : superExternType.externTypes)
+        for (const auto& [superClassTy, superNegations] : superClass.classes)
         {
-            result.orElse(isCovariantWith(env, subExternTypeTy, superExternTypeTy, scope));
+            result.orElse(isCovariantWith(env, subClassTy, superClassTy, scope));
             if (!result.isSubtype)
                 continue;
 
             for (TypeId negation : superNegations)
             {
-                result.andAlso(SubtypingResult::negate(isCovariantWith(env, subExternTypeTy, negation, scope)));
+                result.andAlso(SubtypingResult::negate(isCovariantWith(env, subClassTy, negation, scope)));
                 if (result.isSubtype)
                     break;
             }
@@ -1708,17 +1662,17 @@ SubtypingResult Subtyping::isCovariantWith(
 
 SubtypingResult Subtyping::isCovariantWith(
     SubtypingEnvironment& env,
-    const NormalizedExternType& subExternType,
+    const NormalizedClassType& subClass,
     const TypeIds& superTables,
     NotNull<Scope> scope
 )
 {
-    for (const auto& [subExternTypeTy, _] : subExternType.externTypes)
+    for (const auto& [subClassTy, _] : subClass.classes)
     {
         SubtypingResult result;
 
         for (TypeId superTableTy : superTables)
-            result.orElse(isCovariantWith(env, subExternTypeTy, superTableTy, scope));
+            result.orElse(isCovariantWith(env, subClassTy, superTableTy, scope));
 
         if (!result.isSubtype)
             return result;
@@ -1806,12 +1760,7 @@ SubtypingResult Subtyping::isCovariantWith(SubtypingEnvironment& env, const Type
     {
         results.emplace_back();
         for (TypeId superTy : superTypes)
-        {
             results.back().orElse(isCovariantWith(env, subTy, superTy, scope));
-
-            if (results.back().normalizationTooComplex)
-                return SubtypingResult{false, /* normalizationTooComplex */ true};
-        }
     }
 
     return SubtypingResult::all(results);

Analysis/src/TableLiteralInference.cpp

@@ -13,9 +13,7 @@
 #include "Luau/TypeUtils.h"
 #include "Luau/Unifier2.h"
 
-LUAU_FASTFLAGVARIABLE(LuauBidirectionalInferenceCollectIndexerTypes)
+LUAU_FASTFLAGVARIABLE(LuauBidirectionalInferenceUpcast)
-LUAU_FASTFLAGVARIABLE(LuauBidirectionalFailsafe)
-LUAU_FASTFLAGVARIABLE(LuauBidirectionalInferenceElideAssert)
 
 namespace Luau
 {
@@ -138,33 +136,27 @@ TypeId matchLiteralType(
      * things like replace explicit named properties with indexers as required
      * by the expected type.
      */
-
     if (!isLiteral(expr))
+    {
+        if (FFlag::LuauBidirectionalInferenceUpcast)
         {
             auto result = subtyping->isSubtype(/*subTy=*/exprType, /*superTy=*/expectedType, unifier->scope);
-        return result.isSubtype ? expectedType : exprType;
+            return result.isSubtype
+                ? expectedType
+                : exprType;
+        }
+        else
+            return exprType;
     }
 
     expectedType = follow(expectedType);
     exprType = follow(exprType);
 
-    if (FFlag::LuauBidirectionalInferenceCollectIndexerTypes)
-    {
-        // The intent of `matchLiteralType` is to upcast values when it's safe
-        // to do so. it's always safe to upcast to `any` or `unknown`, so we
-        // can unconditionally do so here.
-        if (is<AnyType, UnknownType>(expectedType))
-            return expectedType;
-    }
-    else
-    {
     if (get<AnyType>(expectedType) || get<UnknownType>(expectedType))
     {
         // "Narrowing" to unknown or any is not going to do anything useful.
         return exprType;
     }
-    }
-
 
     if (expr->is<AstExprConstantString>())
     {
@@ -233,26 +225,19 @@ TypeId matchLiteralType(
     }
 
 
-    if (expr->is<AstExprFunction>())
+    if (FFlag::LuauBidirectionalInferenceUpcast && expr->is<AstExprFunction>())
     {
         // TODO: Push argument / return types into the lambda. For now, just do 
         // the non-literal thing: check for a subtype and upcast if valid.
         auto result = subtyping->isSubtype(/*subTy=*/exprType, /*superTy=*/expectedType, unifier->scope);
-        return result.isSubtype ? expectedType : exprType;
+        return result.isSubtype 
+            ? expectedType
+            : exprType;
     }
 
     if (auto exprTable = expr->as<AstExprTable>())
     {
         TableType* const tableTy = getMutable<TableType>(exprType);
-
-        // This can occur if we have an expression like:
-        //
-        //  { x = {}, x = 42 }
-        //
-        // The type of this will be `{ x: number }`
-        if (FFlag::LuauBidirectionalFailsafe && !tableTy)
-            return exprType;
-
         LUAU_ASSERT(tableTy);
 
         const TableType* expectedTableTy = get<TableType>(expectedType);
@@ -279,9 +264,6 @@ TypeId matchLiteralType(
 
         DenseHashSet<AstExprConstantString*> keysToDelete{nullptr};
 
-        DenseHashSet<TypeId> indexerKeyTypes{nullptr};
-        DenseHashSet<TypeId> indexerValueTypes{nullptr};
-
         for (const AstExprTable::Item& item : exprTable->items)
         {
             if (isRecord(item))
@@ -289,11 +271,6 @@ TypeId matchLiteralType(
                 const AstArray<char>& s = item.key->as<AstExprConstantString>()->value;
                 std::string keyStr{s.data, s.data + s.size};
                 auto it = tableTy->props.find(keyStr);
-
-                // This can occur, potentially, if we are re-entrant.
-                if (FFlag::LuauBidirectionalFailsafe && it == tableTy->props.end())
-                    continue;
-
                 LUAU_ASSERT(it != tableTy->props.end());
 
                 Property& prop = it->second;
@@ -330,20 +307,13 @@ TypeId matchLiteralType(
                             toBlock
                         );
 
-                        if (FFlag::LuauBidirectionalInferenceCollectIndexerTypes)
-                        {
-                            indexerKeyTypes.insert(arena->addType(SingletonType{StringSingleton{keyStr}}));
-                            indexerValueTypes.insert(matchedType);
-                        }
-                        else
-                        {
                         if (tableTy->indexer)
                             unifier->unify(matchedType, tableTy->indexer->indexResultType);
                         else
                             tableTy->indexer = TableIndexer{expectedTableTy->indexer->indexType, matchedType};
-                        }
 
                         keysToDelete.insert(item.key->as<AstExprConstantString>());
+
                     }
 
                     // If it's just an extra property and the expected type
@@ -366,25 +336,22 @@ TypeId matchLiteralType(
                 // quadratic in a hurry.
                 if (expectedProp.isShared())
                 {
-                    matchedType = matchLiteralType(
+                    matchedType =
-                        astTypes, astExpectedTypes, builtinTypes, arena, unifier, subtyping, *expectedReadTy, propTy, item.value, toBlock
+                        matchLiteralType(astTypes, astExpectedTypes, builtinTypes, arena, unifier, subtyping, *expectedReadTy, propTy, item.value, toBlock);
-                    );
                     prop.readTy = matchedType;
                     prop.writeTy = matchedType;
                 }
                 else if (expectedReadTy)
                 {
-                    matchedType = matchLiteralType(
+                    matchedType =
-                        astTypes, astExpectedTypes, builtinTypes, arena, unifier, subtyping, *expectedReadTy, propTy, item.value, toBlock
+                        matchLiteralType(astTypes, astExpectedTypes, builtinTypes, arena, unifier, subtyping, *expectedReadTy, propTy, item.value, toBlock);
-                    );
                     prop.readTy = matchedType;
                     prop.writeTy.reset();
                 }
                 else if (expectedWriteTy)
                 {
-                    matchedType = matchLiteralType(
+                    matchedType =
-                        astTypes, astExpectedTypes, builtinTypes, arena, unifier, subtyping, *expectedWriteTy, propTy, item.value, toBlock
+                        matchLiteralType(astTypes, astExpectedTypes, builtinTypes, arena, unifier, subtyping, *expectedWriteTy, propTy, item.value, toBlock);
-                    );
                     prop.readTy.reset();
                     prop.writeTy = matchedType;
                 }
@@ -401,15 +368,9 @@ TypeId matchLiteralType(
                 LUAU_ASSERT(matchedType);
 
                 (*astExpectedTypes)[item.value] = matchedType;
-                // NOTE: We do *not* add to the potential indexer types here.
-                // I think this is correct to support something like:
-                //
-                //  { [string]: number, foo: boolean }
-                //
             }
             else if (item.kind == AstExprTable::Item::List)
             {
-                if (!FFlag::LuauBidirectionalInferenceCollectIndexerTypes || !FFlag::LuauBidirectionalInferenceElideAssert)
                 LUAU_ASSERT(tableTy->indexer);
 
                 if (expectedTableTy->indexer)
@@ -431,19 +392,11 @@ TypeId matchLiteralType(
                         toBlock
                     );
 
-                    if (FFlag::LuauBidirectionalInferenceCollectIndexerTypes)
-                    {
-                        indexerKeyTypes.insert(builtinTypes->numberType);
-                        indexerValueTypes.insert(matchedType);
-                    }
-                    else
-                    {
                     // if the index result type is the prop type, we can replace it with the matched type here.
                     if (tableTy->indexer->indexResultType == *propTy)
                         tableTy->indexer->indexResultType = matchedType;
                 }
             }
-            }
             else if (item.kind == AstExprTable::Item::General)
             {
 
@@ -463,12 +416,6 @@ TypeId matchLiteralType(
                 // Populate expected types for non-string keys declared with [] (the code below will handle the case where they are strings)
                 if (!item.key->as<AstExprConstantString>() && expectedTableTy->indexer)
                     (*astExpectedTypes)[item.key] = expectedTableTy->indexer->indexType;
-
-                if (FFlag::LuauBidirectionalInferenceCollectIndexerTypes)
-                {
-                    indexerKeyTypes.insert(tKey);
-                    indexerValueTypes.insert(tProp);
-                }
             }
             else
                 LUAU_ASSERT(!"Unexpected");
@@ -530,41 +477,11 @@ TypeId matchLiteralType(
         // have one too.
         // TODO: If the expected table also has an indexer, we might want to
         // push the expected indexer's types into it.
-        if (FFlag::LuauBidirectionalInferenceCollectIndexerTypes && expectedTableTy->indexer)
-        {
-            if (indexerValueTypes.size() > 0 && indexerKeyTypes.size() > 0)
-            {
-                TypeId inferredKeyType = builtinTypes->neverType;
-                TypeId inferredValueType = builtinTypes->neverType;
-                for (auto kt : indexerKeyTypes)
-                {
-                    auto simplified = simplifyUnion(builtinTypes, arena, inferredKeyType, kt);
-                    inferredKeyType = simplified.result;
-                }
-                for (auto vt : indexerValueTypes)
-                {
-                    auto simplified = simplifyUnion(builtinTypes, arena, inferredValueType, vt);
-                    inferredValueType = simplified.result;
-                }
-                tableTy->indexer = TableIndexer{inferredKeyType, inferredValueType};
-                auto keyCheck = subtyping->isSubtype(inferredKeyType, expectedTableTy->indexer->indexType, unifier->scope);
-                if (keyCheck.isSubtype)
-                    tableTy->indexer->indexType = expectedTableTy->indexer->indexType;
-                auto valueCheck = subtyping->isSubtype(inferredValueType, expectedTableTy->indexer->indexResultType, unifier->scope);
-                if (valueCheck.isSubtype)
-                    tableTy->indexer->indexResultType = expectedTableTy->indexer->indexResultType;
-            }
-            else
-                LUAU_ASSERT(indexerKeyTypes.empty() && indexerValueTypes.empty());
-        }
-        else
-        {
         if (expectedTableTy->indexer && !tableTy->indexer)
         {
             tableTy->indexer = expectedTableTy->indexer;
         }
     }
-    }
 
     return exprType;
 }

Analysis/src/ToDot.cpp

@@ -299,9 +299,9 @@ void StateDot::visitChildren(TypeId ty, int index)
             finishNodeLabel(ty);
             finishNode();
         }
-        else if constexpr (std::is_same_v<T, ExternType>)
+        else if constexpr (std::is_same_v<T, ClassType>)
         {
-            formatAppend(result, "ExternType %s", t.name.c_str());
+            formatAppend(result, "ClassType %s", t.name.c_str());
             finishNodeLabel(ty);
             finishNode();
 

Analysis/src/ToString.cpp

@@ -19,11 +19,8 @@
 #include <stdexcept>
 #include <string>
 
-LUAU_FASTFLAGVARIABLE(LuauEnableDenseTableAlias)
-
 LUAU_FASTFLAG(LuauSolverV2)
 LUAU_FASTFLAGVARIABLE(LuauSyntheticErrors)
-LUAU_FASTFLAGVARIABLE(LuauStringPartLengthLimit)
 
 /*
  * Enables increasing levels of verbosity for Luau type names when stringifying.
@@ -123,7 +120,7 @@ struct FindCyclicTypes final : TypeVisitor
         return true;
     }
 
-    bool visit(TypeId ty, const ExternType&) override
+    bool visit(TypeId ty, const ClassType&) override
     {
         return false;
     }
@@ -304,28 +301,6 @@ struct StringifierState
         emit(std::to_string(i).c_str());
     }
 
-    void emit(Polarity p)
-    {
-        switch (p)
-        {
-        case Polarity::None:
-            emit("  ");
-            break;
-        case Polarity::Negative:
-            emit(" -");
-            break;
-        case Polarity::Positive:
-            emit("+ ");
-            break;
-        case Polarity::Mixed:
-            emit("+-");
-            break;
-        default:
-            emit("!!");
-            break;
-        }
-    }
-
     void indent()
     {
         indentation += 4;
@@ -507,8 +482,6 @@ struct TypeStringifier
             {
                 state.emit("'");
                 state.emit(state.getName(ty));
-                if (FInt::DebugLuauVerboseTypeNames >= 1)
-                    state.emit(ftv.polarity);
             }
             else
             {
@@ -521,9 +494,6 @@ struct TypeStringifier
                 state.emit("'");
                 state.emit(state.getName(ty));
 
-                if (FInt::DebugLuauVerboseTypeNames >= 1)
-                    state.emit(ftv.polarity);
-
                 if (!get<UnknownType>(upperBound))
                 {
                     state.emit(" <: ");
@@ -539,9 +509,6 @@ struct TypeStringifier
 
         state.emit(state.getName(ty));
 
-        if (FFlag::LuauSolverV2 && FInt::DebugLuauVerboseTypeNames >= 1)
-            state.emit(ftv.polarity);
-
         if (FInt::DebugLuauVerboseTypeNames >= 2)
         {
             state.emit("-");
@@ -571,9 +538,6 @@ struct TypeStringifier
         else
             state.emit(state.getName(ty));
 
-        if (FInt::DebugLuauVerboseTypeNames >= 1)
-            state.emit(gtv.polarity);
-
         if (FInt::DebugLuauVerboseTypeNames >= 2)
         {
             state.emit("-");
@@ -722,13 +686,7 @@ struct TypeStringifier
         if (ttv.boundTo)
             return stringify(*ttv.boundTo);
 
-        bool showName = !state.exhaustive;
+        if (!state.exhaustive)
-        if (FFlag::LuauEnableDenseTableAlias)
-        {
-            // if hide table alias expansions are enabled and there is a name found for the table, use it
-            showName = !state.exhaustive || state.opts.hideTableAliasExpansions;
-        }
-        if (showName)
         {
             if (ttv.name)
             {
@@ -751,10 +709,6 @@ struct TypeStringifier
                 stringify(ttv.instantiatedTypeParams, ttv.instantiatedTypePackParams);
                 return;
             }
-        }
-
-        if (!state.exhaustive)
-        {
             if (ttv.syntheticName)
             {
                 state.result.invalid = true;
@@ -893,9 +847,9 @@ struct TypeStringifier
         state.emit(" }");
     }
 
-    void operator()(TypeId, const ExternType& etv)
+    void operator()(TypeId, const ClassType& ctv)
     {
-        state.emit(etv.name);
+        state.emit(ctv.name);
     }
 
     void operator()(TypeId, const AnyType&)
@@ -923,9 +877,6 @@ struct TypeStringifier
         bool hasNonNilDisjunct = false;
 
         std::vector<std::string> results = {};
-        size_t resultsLength = 0;
-        bool lengthLimitHit = false;
-
         for (auto el : &uv)
         {
             el = follow(el);
@@ -952,34 +903,14 @@ struct TypeStringifier
             if (needParens)
                 state.emit(")");
 
-            if (FFlag::LuauStringPartLengthLimit)
-                resultsLength += state.result.name.length();
-
             results.push_back(std::move(state.result.name));
-
             state.result.name = std::move(saved);
-
-            if (FFlag::LuauStringPartLengthLimit)
-            {
-                lengthLimitHit = state.opts.maxTypeLength > 0 && resultsLength > state.opts.maxTypeLength;
-
-                if (lengthLimitHit)
-                    break;
-            }
         }
 
         state.unsee(&uv);
 
-        if (FFlag::LuauStringPartLengthLimit)
-        {
-            if (!lengthLimitHit && !FFlag::DebugLuauToStringNoLexicalSort)
-                std::sort(results.begin(), results.end());
-        }
-        else
-        {
         if (!FFlag::DebugLuauToStringNoLexicalSort)
             std::sort(results.begin(), results.end());
-        }
 
         if (optional && results.size() > 1)
             state.emit("(");
@@ -1023,9 +954,6 @@ struct TypeStringifier
         }
 
         std::vector<std::string> results = {};
-        size_t resultsLength = 0;
-        bool lengthLimitHit = false;
-
         for (auto el : uv.parts)
         {
             el = follow(el);
@@ -1042,34 +970,14 @@ struct TypeStringifier
             if (needParens)
                 state.emit(")");
 
-            if (FFlag::LuauStringPartLengthLimit)
-                resultsLength += state.result.name.length();
-
             results.push_back(std::move(state.result.name));
-
             state.result.name = std::move(saved);
-
-            if (FFlag::LuauStringPartLengthLimit)
-            {
-                lengthLimitHit = state.opts.maxTypeLength > 0 && resultsLength > state.opts.maxTypeLength;
-
-                if (lengthLimitHit)
-                    break;
-            }
         }
 
         state.unsee(&uv);
 
-        if (FFlag::LuauStringPartLengthLimit)
-        {
-            if (!lengthLimitHit && !FFlag::DebugLuauToStringNoLexicalSort)
-                std::sort(results.begin(), results.end());
-        }
-        else
-        {
         if (!FFlag::DebugLuauToStringNoLexicalSort)
             std::sort(results.begin(), results.end());
-        }
 
         bool first = true;
         bool shouldPlaceOnNewlines = results.size() > state.opts.compositeTypesSingleLineLimit || isOverloadedFunction(ty);
@@ -1314,9 +1222,6 @@ struct TypePackStringifier
             state.emit(state.getName(tp));
         }
 
-        if (FInt::DebugLuauVerboseTypeNames >= 1)
-            state.emit(pack.polarity);
-
         if (FInt::DebugLuauVerboseTypeNames >= 2)
         {
             state.emit("-");
@@ -1336,9 +1241,6 @@ struct TypePackStringifier
             state.emit("free-");
         state.emit(state.getName(tp));
 
-        if (FInt::DebugLuauVerboseTypeNames >= 1)
-            state.emit(pack.polarity);
-
         if (FInt::DebugLuauVerboseTypeNames >= 2)
         {
             state.emit("-");

Analysis/src/TopoSortStatements.cpp

@@ -41,8 +41,6 @@
 #include <stdexcept>
 #include <optional>
 
-LUAU_FASTFLAG(LuauStoreReturnTypesAsPackOnAst)
-
 namespace Luau
 {
 
@@ -299,11 +297,6 @@ struct ArcCollector : public AstVisitor
             add(*name);
         return true;
     }
-
-    bool visit(AstTypePack* node) override
-    {
-        return FFlag::LuauStoreReturnTypesAsPackOnAst;
-    }
 };
 
 struct ContainsFunctionCall : public AstVisitor

Analysis/src/Transpiler.cpp

@@ -10,11 +10,11 @@
 #include <limits>
 #include <math.h>
 
-LUAU_FASTFLAG(LuauStoreCSTData2)
+LUAU_FASTFLAG(LuauStoreCSTData)
+LUAU_FASTFLAG(LuauExtendStatEndPosWithSemicolon)
 LUAU_FASTFLAG(LuauAstTypeGroup3)
-LUAU_FASTFLAG(LuauParseOptionalAsNode2)
+LUAU_FASTFLAG(LuauFixDoBlockEndLocation)
-LUAU_FASTFLAG(LuauFixFunctionWithAttributesStartLocation)
+LUAU_FASTFLAG(LuauParseOptionalAsNode)
-LUAU_FASTFLAG(LuauStoreReturnTypesAsPackOnAst)
 
 namespace
 {
@@ -167,7 +167,7 @@ struct StringWriter : Writer
 
     void symbol(std::string_view s) override
     {
-        if (FFlag::LuauStoreCSTData2)
+        if (FFlag::LuauStoreCSTData)
         {
             write(s);
         }
@@ -257,7 +257,7 @@ public:
             first = !first;
         else
         {
-            if (FFlag::LuauStoreCSTData2 && commaPosition)
+            if (FFlag::LuauStoreCSTData && commaPosition)
             {
                 writer.advance(*commaPosition);
                 commaPosition++;
@@ -331,7 +331,7 @@ struct Printer_DEPRECATED
         }
     }
 
-    void visualizeTypePackAnnotation(const AstTypePack& annotation, bool forVarArg, bool unconditionallyParenthesize = true)
+    void visualizeTypePackAnnotation(const AstTypePack& annotation, bool forVarArg)
     {
         advance(annotation.location.begin);
         if (const AstTypePackVariadic* variadicTp = annotation.as<AstTypePackVariadic>())
@@ -349,7 +349,7 @@ struct Printer_DEPRECATED
         else if (const AstTypePackExplicit* explicitTp = annotation.as<AstTypePackExplicit>())
         {
             LUAU_ASSERT(!forVarArg);
-            visualizeTypeList(explicitTp->typeList, unconditionallyParenthesize);
+            visualizeTypeList(explicitTp->typeList, true);
         }
         else
         {
@@ -705,6 +705,8 @@ struct Printer_DEPRECATED
             writer.keyword("do");
             for (const auto& s : block->body)
                 visualize(*s);
+            if (!FFlag::LuauFixDoBlockEndLocation)
+                writer.advance(block->location.end);
             writeEnd(program.location);
         }
         else if (const auto& a = program.as<AstStatIf>())
@@ -1063,15 +1065,12 @@ struct Printer_DEPRECATED
 
         writer.symbol(")");
 
-        if (writeTypes && (FFlag::LuauStoreReturnTypesAsPackOnAst ? func.returnAnnotation != nullptr : func.returnAnnotation_DEPRECATED.has_value()))
+        if (writeTypes && func.returnAnnotation)
         {
             writer.symbol(":");
             writer.space();
 
-            if (FFlag::LuauStoreReturnTypesAsPackOnAst)
+            visualizeTypeList(*func.returnAnnotation, false);
-                visualizeTypePackAnnotation(*func.returnAnnotation, false, false);
-            else
-                visualizeTypeList(*func.returnAnnotation_DEPRECATED, false);
         }
 
         visualizeBlock(*func.body);
@@ -1175,10 +1174,7 @@ struct Printer_DEPRECATED
             }
 
             writer.symbol("->");
-            if (FFlag::LuauStoreReturnTypesAsPackOnAst)
+            visualizeTypeList(a->returnTypes, true);
-                visualizeTypePackAnnotation(*a->returnTypes, false);
-            else
-                visualizeTypeList(a->returnTypes_DEPRECATED, true);
         }
         else if (const auto& a = typeAnnotation.as<AstTypeTable>())
         {
@@ -1233,18 +1229,9 @@ struct Printer_DEPRECATED
                 AstType* l = a->types.data[0];
                 AstType* r = a->types.data[1];
 
-                if (FFlag::LuauParseOptionalAsNode2)
-                {
-                    auto lta = l->as<AstTypeReference>();
-                    if (lta && lta->name == "nil" && !r->is<AstTypeOptional>())
-                        std::swap(l, r);
-                }
-                else
-                {
                 auto lta = l->as<AstTypeReference>();
                 if (lta && lta->name == "nil")
                     std::swap(l, r);
-                }
 
                 // it's still possible that we had a (T | U) or (T | nil) and not (nil | T)
                 auto rta = r->as<AstTypeReference>();
@@ -1267,7 +1254,7 @@ struct Printer_DEPRECATED
 
             for (size_t i = 0; i < a->types.size; ++i)
             {
-                if (FFlag::LuauParseOptionalAsNode2)
+                if (FFlag::LuauParseOptionalAsNode)
                 {
                     if (a->types.data[i]->is<AstTypeOptional>())
                     {
@@ -1372,7 +1359,7 @@ struct Printer
         }
     }
 
-    void visualizeTypePackAnnotation(AstTypePack& annotation, bool forVarArg, bool unconditionallyParenthesize = true)
+    void visualizeTypePackAnnotation(AstTypePack& annotation, bool forVarArg)
     {
         advance(annotation.location.begin);
         if (const AstTypePackVariadic* variadicTp = annotation.as<AstTypePackVariadic>())
@@ -1394,10 +1381,10 @@ struct Printer
             LUAU_ASSERT(!forVarArg);
             if (const auto cstNode = lookupCstNode<CstTypePackExplicit>(explicitTp))
                 visualizeTypeList(
-                    explicitTp->typeList, FFlag::LuauStoreReturnTypesAsPackOnAst ? cstNode->hasParentheses : true, cstNode->openParenthesesPosition, cstNode->closeParenthesesPosition, cstNode->commaPositions
+                    explicitTp->typeList, true, cstNode->openParenthesesPosition, cstNode->closeParenthesesPosition, cstNode->commaPositions
                 );
             else
-                visualizeTypeList(explicitTp->typeList, unconditionallyParenthesize);
+                visualizeTypeList(explicitTp->typeList, true);
         }
         else
         {
@@ -1502,7 +1489,6 @@ struct Printer
 
     void visualize(AstExpr& expr)
     {
-        if (!expr.is<AstExprFunction>() || FFlag::LuauFixFunctionWithAttributesStartLocation)
         advance(expr.location.begin);
 
         if (const auto& a = expr.as<AstExprGroup>())
@@ -1637,17 +1623,6 @@ struct Printer
         }
         else if (const auto& a = expr.as<AstExprFunction>())
         {
-            for (const auto& attribute : a->attributes)
-                visualizeAttribute(*attribute);
-            if (FFlag::LuauFixFunctionWithAttributesStartLocation)
-            {
-                if (const auto cstNode = lookupCstNode<CstExprFunction>(a))
-                    advance(cstNode->functionKeywordPosition);
-            }
-            else
-            {
-                advance(a->location.begin);
-            }
             writer.keyword("function");
             visualizeFunctionBody(*a);
         }
@@ -1899,7 +1874,6 @@ struct Printer
 
     void visualize(AstStat& program)
     {
-        if ((!program.is<AstStatLocalFunction>() && !program.is<AstStatFunction>()) || FFlag::LuauFixFunctionWithAttributesStartLocation)
         advance(program.location.begin);
 
         if (const auto& block = program.as<AstStatBlock>())
@@ -2137,36 +2111,13 @@ struct Printer
         }
         else if (const auto& a = program.as<AstStatFunction>())
         {
-            for (const auto& attribute : a->func->attributes)
-                visualizeAttribute(*attribute);
-            if (FFlag::LuauFixFunctionWithAttributesStartLocation)
-            {
-                if (const auto cstNode = lookupCstNode<CstStatFunction>(a))
-                    advance(cstNode->functionKeywordPosition);
-            }
-            else
-            {
-                advance(a->location.begin);
-            }
             writer.keyword("function");
             visualize(*a->name);
             visualizeFunctionBody(*a->func);
         }
         else if (const auto& a = program.as<AstStatLocalFunction>())
         {
-            for (const auto& attribute : a->func->attributes)
-                visualizeAttribute(*attribute);
-
             const auto cstNode = lookupCstNode<CstStatLocalFunction>(a);
-            if (FFlag::LuauFixFunctionWithAttributesStartLocation)
-            {
-                if (cstNode)
-                    advance(cstNode->localKeywordPosition);
-            }
-            else
-            {
-                advance(a->location.begin);
-            }
 
             writer.keyword("local");
 
@@ -2310,7 +2261,7 @@ struct Printer
 
         if (program.hasSemicolon)
         {
-            if (FFlag::LuauStoreCSTData2)
+            if (FFlag::LuauStoreCSTData)
                 advanceBefore(program.location.end, 1);
             writer.symbol(";");
         }
@@ -2320,6 +2271,8 @@ struct Printer
     {
         const auto cstNode = lookupCstNode<CstExprFunction>(&func);
 
+        // TODO(CLI-139347): need to handle attributes, argument types, and return type (incl. parentheses of return type)
+
         if (func.generics.size > 0 || func.genericPacks.size > 0)
         {
             CommaSeparatorInserter comma(writer, cstNode ? cstNode->genericsCommaPositions.begin() : nullptr);
@@ -2385,23 +2338,14 @@ struct Printer
             advanceBefore(func.argLocation->end, 1);
         writer.symbol(")");
 
-        if (writeTypes && FFlag::LuauStoreReturnTypesAsPackOnAst ? func.returnAnnotation != nullptr : func.returnAnnotation_DEPRECATED.has_value())
+        if (writeTypes && func.returnAnnotation)
         {
             if (cstNode)
                 advance(cstNode->returnSpecifierPosition);
             writer.symbol(":");
+            writer.space();
 
-            if (FFlag::LuauStoreReturnTypesAsPackOnAst)
+            visualizeTypeList(*func.returnAnnotation, false);
-            {
-                if (!cstNode)
-                    writer.space();
-                visualizeTypePackAnnotation(*func.returnAnnotation, false, false);
-            }
-            else
-            {
-                writer.space();
-                visualizeTypeList(*func.returnAnnotation_DEPRECATED, false);
-            }
         }
 
         visualizeBlock(*func.body);
@@ -2483,23 +2427,6 @@ struct Printer
         }
     }
 
-    void visualizeAttribute(AstAttr& attribute)
-    {
-        advance(attribute.location.begin);
-        switch (attribute.type)
-        {
-        case AstAttr::Checked:
-            writer.keyword("@checked");
-            break;
-        case AstAttr::Native:
-            writer.keyword("@native");
-            break;
-        case AstAttr::Deprecated:
-            writer.keyword("@deprecated");
-            break;
-        }
-    }
-
     void visualizeTypeAnnotation(AstType& typeAnnotation)
     {
         advance(typeAnnotation.location.begin);
@@ -2584,10 +2511,7 @@ struct Printer
             if (cstNode)
                 advance(cstNode->returnArrowPosition);
             writer.symbol("->");
-            if (FFlag::LuauStoreReturnTypesAsPackOnAst)
+            visualizeTypeList(a->returnTypes, true);
-                visualizeTypePackAnnotation(*a->returnTypes, false);
-            else
-                visualizeTypeList(a->returnTypes_DEPRECATED, true);
         }
         else if (const auto& a = typeAnnotation.as<AstTypeTable>())
         {
@@ -2660,7 +2584,6 @@ struct Printer
                             {
                                 advance(item.indexerOpenPosition);
                                 writer.symbol("[");
-                                advance(item.stringPosition);
                                 writer.sourceString(
                                     std::string_view(item.stringInfo->sourceString.data, item.stringInfo->sourceString.size),
                                     item.stringInfo->quoteStyle,
@@ -2748,25 +2671,14 @@ struct Printer
         }
         else if (const auto& a = typeAnnotation.as<AstTypeUnion>())
         {
-            const auto cstNode = lookupCstNode<CstTypeUnion>(a);
+            if (a->types.size == 2)
-
-            if (!cstNode && a->types.size == 2)
             {
                 AstType* l = a->types.data[0];
                 AstType* r = a->types.data[1];
 
-                if (FFlag::LuauParseOptionalAsNode2)
-                {
-                    auto lta = l->as<AstTypeReference>();
-                    if (lta && lta->name == "nil" && !r->is<AstTypeOptional>())
-                        std::swap(l, r);
-                }
-                else
-                {
                 auto lta = l->as<AstTypeReference>();
                 if (lta && lta->name == "nil")
                     std::swap(l, r);
-                }
 
                 // it's still possible that we had a (T | U) or (T | nil) and not (nil | T)
                 auto rta = r->as<AstTypeReference>();
@@ -2787,20 +2699,12 @@ struct Printer
                 }
             }
 
-            if (cstNode && cstNode->leadingPosition)
-            {
-                advance(*cstNode->leadingPosition);
-                writer.symbol("|");
-            }
-
-            size_t separatorIndex = 0;
             for (size_t i = 0; i < a->types.size; ++i)
             {
-                if (FFlag::LuauParseOptionalAsNode2)
+                if (FFlag::LuauParseOptionalAsNode)
                 {
-                    if (const auto optional = a->types.data[i]->as<AstTypeOptional>())
+                    if (a->types.data[i]->is<AstTypeOptional>())
                     {
-                        advance(optional->location.begin);
                         writer.symbol("?");
                         continue;
                     }
@@ -2808,18 +2712,11 @@ struct Printer
 
                 if (i > 0)
                 {
-                    if (cstNode && FFlag::LuauParseOptionalAsNode2)
-                    {
-                        // separatorIndex is only valid if `?` is handled as an AstTypeOptional
-                        advance(cstNode->separatorPositions.data[separatorIndex]);
-                        separatorIndex++;
-                    }
-                    else
                     writer.maybeSpace(a->types.data[i]->location.begin, 2);
                     writer.symbol("|");
                 }
 
-                bool wrap = !cstNode && (a->types.data[i]->as<AstTypeIntersection>() || a->types.data[i]->as<AstTypeFunction>());
+                bool wrap = a->types.data[i]->as<AstTypeIntersection>() || a->types.data[i]->as<AstTypeFunction>();
 
                 if (wrap)
                     writer.symbol("(");
@@ -2832,27 +2729,15 @@ struct Printer
         }
         else if (const auto& a = typeAnnotation.as<AstTypeIntersection>())
         {
-            const auto cstNode = lookupCstNode<CstTypeIntersection>(a);
-
-            // If the sizes are equal, we know there is a leading & token
-            if (cstNode && cstNode->leadingPosition)
-            {
-                advance(*cstNode->leadingPosition);
-                writer.symbol("&");
-            }
-
             for (size_t i = 0; i < a->types.size; ++i)
             {
                 if (i > 0)
                 {
-                    if (cstNode)
-                        advance(cstNode->separatorPositions.data[i - 1]);
-                    else
                     writer.maybeSpace(a->types.data[i]->location.begin, 2);
                     writer.symbol("&");
                 }
 
-                bool wrap = !cstNode && (a->types.data[i]->as<AstTypeUnion>() || a->types.data[i]->as<AstTypeFunction>());
+                bool wrap = a->types.data[i]->as<AstTypeUnion>() || a->types.data[i]->as<AstTypeFunction>();
 
                 if (wrap)
                     writer.symbol("(");
@@ -2901,7 +2786,7 @@ std::string toString(AstNode* node)
     StringWriter writer;
     writer.pos = node->location.begin;
 
-    if (FFlag::LuauStoreCSTData2)
+    if (FFlag::LuauStoreCSTData)
     {
         Printer printer(writer, CstNodeMap{nullptr});
         printer.writeTypes = true;
@@ -2937,7 +2822,7 @@ void dump(AstNode* node)
 std::string transpile(AstStatBlock& block, const CstNodeMap& cstNodeMap)
 {
     StringWriter writer;
-    if (FFlag::LuauStoreCSTData2)
+    if (FFlag::LuauStoreCSTData)
     {
         Printer(writer, cstNodeMap).visualizeBlock(block);
     }
@@ -2951,7 +2836,7 @@ std::string transpile(AstStatBlock& block, const CstNodeMap& cstNodeMap)
 std::string transpileWithTypes(AstStatBlock& block, const CstNodeMap& cstNodeMap)
 {
     StringWriter writer;
-    if (FFlag::LuauStoreCSTData2)
+    if (FFlag::LuauStoreCSTData)
     {
         Printer printer(writer, cstNodeMap);
         printer.writeTypes = true;

Analysis/src/TxnLog.cpp

@@ -407,6 +407,41 @@ PendingTypePack* TxnLog::changeLevel(TypePackId tp, TypeLevel newLevel)
     return newTp;
 }
 
+PendingType* TxnLog::changeScope(TypeId ty, NotNull<Scope> newScope)
+{
+    LUAU_ASSERT(get<FreeType>(ty) || get<TableType>(ty) || get<FunctionType>(ty));
+
+    PendingType* newTy = queue(ty);
+    if (FreeType* ftv = Luau::getMutable<FreeType>(newTy))
+    {
+        ftv->scope = newScope;
+    }
+    else if (TableType* ttv = Luau::getMutable<TableType>(newTy))
+    {
+        LUAU_ASSERT(ttv->state == TableState::Free || ttv->state == TableState::Generic);
+        ttv->scope = newScope;
+    }
+    else if (FunctionType* ftv = Luau::getMutable<FunctionType>(newTy))
+    {
+        ftv->scope = newScope;
+    }
+
+    return newTy;
+}
+
+PendingTypePack* TxnLog::changeScope(TypePackId tp, NotNull<Scope> newScope)
+{
+    LUAU_ASSERT(get<FreeTypePack>(tp));
+
+    PendingTypePack* newTp = queue(tp);
+    if (FreeTypePack* ftp = Luau::getMutable<FreeTypePack>(newTp))
+    {
+        ftp->scope = newScope;
+    }
+
+    return newTp;
+}
+
 PendingType* TxnLog::changeIndexer(TypeId ty, std::optional<TableIndexer> indexer)
 {
     LUAU_ASSERT(get<TableType>(ty));

Analysis/src/Type.cpp

@@ -282,8 +282,8 @@ std::optional<TypeId> getMetatable(TypeId type, NotNull<BuiltinTypes> builtinTyp
 
     if (const MetatableType* mtType = get<MetatableType>(type))
         return mtType->metatable;
-    else if (const ExternType* externType = get<ExternType>(type))
+    else if (const ClassType* classType = get<ClassType>(type))
-        return externType->metatable;
+        return classType->metatable;
     else if (isString(type))
     {
         auto ptv = get<PrimitiveType>(builtinTypes->stringType);
@@ -346,10 +346,10 @@ std::optional<ModuleName> getDefinitionModuleName(TypeId type)
         if (ftv->definition)
             return ftv->definition->definitionModuleName;
     }
-    else if (auto etv = get<ExternType>(type))
+    else if (auto ctv = get<ClassType>(type))
     {
-        if (!etv->definitionModuleName.empty())
+        if (!ctv->definitionModuleName.empty())
-            return etv->definitionModuleName;
+            return ctv->definitionModuleName;
     }
 
     return std::nullopt;
@@ -488,12 +488,11 @@ FreeType::FreeType(TypeLevel level, TypeId lowerBound, TypeId upperBound)
 {
 }
 
-FreeType::FreeType(Scope* scope, TypeId lowerBound, TypeId upperBound, Polarity polarity)
+FreeType::FreeType(Scope* scope, TypeId lowerBound, TypeId upperBound)
     : index(Unifiable::freshIndex())
     , scope(scope)
     , lowerBound(lowerBound)
     , upperBound(upperBound)
-    , polarity(polarity)
 {
 }
 
@@ -506,6 +505,31 @@ FreeType::FreeType(Scope* scope, TypeLevel level, TypeId lowerBound, TypeId uppe
 {
 }
 
+// Old constructors
+FreeType::FreeType(TypeLevel level)
+    : index(Unifiable::freshIndex())
+    , level(level)
+    , scope(nullptr)
+{
+    LUAU_ASSERT(!FFlag::LuauFreeTypesMustHaveBounds);
+}
+
+FreeType::FreeType(Scope* scope)
+    : index(Unifiable::freshIndex())
+    , level{}
+    , scope(scope)
+{
+    LUAU_ASSERT(!FFlag::LuauFreeTypesMustHaveBounds);
+}
+
+FreeType::FreeType(Scope* scope, TypeLevel level)
+    : index(Unifiable::freshIndex())
+    , level(level)
+    , scope(scope)
+{
+    LUAU_ASSERT(!FFlag::LuauFreeTypesMustHaveBounds);
+}
+
 GenericType::GenericType()
     : index(Unifiable::freshIndex())
     , name("g" + std::to_string(index))
@@ -519,18 +543,16 @@ GenericType::GenericType(TypeLevel level)
 {
 }
 
-GenericType::GenericType(const Name& name, Polarity polarity)
+GenericType::GenericType(const Name& name)
     : index(Unifiable::freshIndex())
     , name(name)
     , explicitName(true)
-    , polarity(polarity)
 {
 }
 
-GenericType::GenericType(Scope* scope, Polarity polarity)
+GenericType::GenericType(Scope* scope)
     : index(Unifiable::freshIndex())
     , scope(scope)
-    , polarity(polarity)
 {
 }
 
@@ -608,6 +630,23 @@ FunctionType::FunctionType(TypeLevel level, TypePackId argTypes, TypePackId retT
 {
 }
 
+FunctionType::FunctionType(
+    TypeLevel level,
+    Scope* scope,
+    TypePackId argTypes,
+    TypePackId retTypes,
+    std::optional<FunctionDefinition> defn,
+    bool hasSelf
+)
+    : definition(std::move(defn))
+    , level(level)
+    , scope(scope)
+    , argTypes(argTypes)
+    , retTypes(retTypes)
+    , hasSelf(hasSelf)
+{
+}
+
 FunctionType::FunctionType(
     std::vector<TypeId> generics,
     std::vector<TypePackId> genericPacks,
@@ -644,6 +683,27 @@ FunctionType::FunctionType(
 {
 }
 
+FunctionType::FunctionType(
+    TypeLevel level,
+    Scope* scope,
+    std::vector<TypeId> generics,
+    std::vector<TypePackId> genericPacks,
+    TypePackId argTypes,
+    TypePackId retTypes,
+    std::optional<FunctionDefinition> defn,
+    bool hasSelf
+)
+    : definition(std::move(defn))
+    , generics(generics)
+    , genericPacks(genericPacks)
+    , level(level)
+    , scope(scope)
+    , argTypes(argTypes)
+    , retTypes(retTypes)
+    , hasSelf(hasSelf)
+{
+}
+
 Property::Property() {}
 
 Property::Property(
@@ -989,7 +1049,7 @@ BuiltinTypes::BuiltinTypes()
     , threadType(arena->addType(Type{PrimitiveType{PrimitiveType::Thread}, /*persistent*/ true}))
     , bufferType(arena->addType(Type{PrimitiveType{PrimitiveType::Buffer}, /*persistent*/ true}))
     , functionType(arena->addType(Type{PrimitiveType{PrimitiveType::Function}, /*persistent*/ true}))
-    , externType(arena->addType(Type{ExternType{"class", {}, std::nullopt, std::nullopt, {}, {}, {}, {}}, /*persistent*/ true}))
+    , classType(arena->addType(Type{ClassType{"class", {}, std::nullopt, std::nullopt, {}, {}, {}, {}}, /*persistent*/ true}))
     , tableType(arena->addType(Type{PrimitiveType{PrimitiveType::Table}, /*persistent*/ true}))
     , emptyTableType(arena->addType(Type{TableType{TableState::Sealed, TypeLevel{}, nullptr}, /*persistent*/ true}))
     , trueType(arena->addType(Type{SingletonType{BooleanSingleton{true}}, /*persistent*/ true}))
@@ -1001,7 +1061,6 @@ BuiltinTypes::BuiltinTypes()
     , noRefineType(arena->addType(Type{NoRefineType{}, /*persistent*/ true}))
     , falsyType(arena->addType(Type{UnionType{{falseType, nilType}}, /*persistent*/ true}))
     , truthyType(arena->addType(Type{NegationType{falsyType}, /*persistent*/ true}))
-    , notNilType(arena->addType(Type{NegationType{nilType}, /*persistent*/ true}))
     , optionalNumberType(arena->addType(Type{UnionType{{numberType, nilType}}, /*persistent*/ true}))
     , optionalStringType(arena->addType(Type{UnionType{{stringType, nilType}}, /*persistent*/ true}))
     , emptyTypePack(arena->addTypePack(TypePackVar{TypePack{{}}, /*persistent*/ true}))
@@ -1080,9 +1139,9 @@ void persist(TypeId ty)
                 queue.push_back(ttv->indexer->indexResultType);
             }
         }
-        else if (auto etv= get<ExternType>(t))
+        else if (auto ctv = get<ClassType>(t))
         {
-            for (const auto& [_name, prop] : etv->props)
+            for (const auto& [_name, prop] : ctv->props)
                 queue.push_back(prop.type());
         }
         else if (auto utv = get<UnionType>(t))
@@ -1182,7 +1241,7 @@ std::optional<TypeLevel> getLevel(TypePackId tp)
         return std::nullopt;
 }
 
-const Property* lookupExternTypeProp(const ExternType* cls, const Name& name)
+const Property* lookupClassProp(const ClassType* cls, const Name& name)
 {
     while (cls)
     {
@@ -1191,7 +1250,7 @@ const Property* lookupExternTypeProp(const ExternType* cls, const Name& name)
             return &it->second;
 
         if (cls->parent)
-            cls = get<ExternType>(*cls->parent);
+            cls = get<ClassType>(*cls->parent);
         else
             return nullptr;
 
@@ -1201,7 +1260,7 @@ const Property* lookupExternTypeProp(const ExternType* cls, const Name& name)
     return nullptr;
 }
 
-bool isSubclass(const ExternType* cls, const ExternType* parent)
+bool isSubclass(const ClassType* cls, const ClassType* parent)
 {
     while (cls)
     {
@@ -1210,7 +1269,7 @@ bool isSubclass(const ExternType* cls, const ExternType* parent)
         else if (!cls->parent)
             return false;
 
-        cls = get<ExternType>(*cls->parent);
+        cls = get<ClassType>(*cls->parent);
         LUAU_ASSERT(cls);
     }
 
@@ -1247,9 +1306,9 @@ IntersectionTypeIterator end(const IntersectionType* itv)
     return IntersectionTypeIterator{};
 }
 
-TypeId freshType(NotNull<TypeArena> arena, NotNull<BuiltinTypes> builtinTypes, Scope* scope, Polarity polarity)
+TypeId freshType(NotNull<TypeArena> arena, NotNull<BuiltinTypes> builtinTypes, Scope* scope)
 {
-    return arena->addType(FreeType{scope, builtinTypes->neverType, builtinTypes->unknownType, polarity});
+    return arena->addType(FreeType{scope, builtinTypes->neverType, builtinTypes->unknownType});
 }
 
 std::vector<TypeId> filterMap(TypeId type, TypeIdPredicate predicate)
@@ -1279,8 +1338,8 @@ static Tags* getTags(TypeId ty)
         return &ftv->tags;
     else if (auto ttv = getMutable<TableType>(ty))
         return &ttv->tags;
-    else if (auto etv = getMutable<ExternType>(ty))
+    else if (auto ctv = getMutable<ClassType>(ty))
-        return &etv->tags;
+        return &ctv->tags;
 
     return nullptr;
 }
@@ -1310,19 +1369,19 @@ bool hasTag(TypeId ty, const std::string& tagName)
 {
     ty = follow(ty);
 
-    // We special case extern types because getTags only returns a pointer to one vector of tags.
+    // We special case classes because getTags only returns a pointer to one vector of tags.
-    // But extern types has multiple vector of tags, represented throughout the hierarchy.
+    // But classes has multiple vector of tags, represented throughout the hierarchy.
-    if (auto etv = get<ExternType>(ty))
+    if (auto ctv = get<ClassType>(ty))
     {
-        while (etv)
+        while (ctv)
         {
-            if (hasTag(etv->tags, tagName))
+            if (hasTag(ctv->tags, tagName))
                 return true;
-            else if (!etv->parent)
+            else if (!ctv->parent)
                 return false;
 
-            etv = get<ExternType>(*etv->parent);
+            ctv = get<ClassType>(*ctv->parent);
-            LUAU_ASSERT(etv);
+            LUAU_ASSERT(ctv);
         }
     }
     else if (auto tags = getTags(ty))

Analysis/src/TypeArena.cpp

@@ -50,9 +50,36 @@ TypeId TypeArena::freshType(NotNull<BuiltinTypes> builtins, Scope* scope, TypeLe
     return allocated;
 }
 
-TypePackId TypeArena::freshTypePack(Scope* scope, Polarity polarity)
+TypeId TypeArena::freshType_DEPRECATED(TypeLevel level)
 {
-    TypePackId allocated = typePacks.allocate(FreeTypePack{scope, polarity});
+    TypeId allocated = types.allocate(FreeType{level});
+
+    asMutable(allocated)->owningArena = this;
+
+    return allocated;
+}
+
+TypeId TypeArena::freshType_DEPRECATED(Scope* scope)
+{
+    TypeId allocated = types.allocate(FreeType{scope});
+
+    asMutable(allocated)->owningArena = this;
+
+    return allocated;
+}
+
+TypeId TypeArena::freshType_DEPRECATED(Scope* scope, TypeLevel level)
+{
+    TypeId allocated = types.allocate(FreeType{scope, level});
+
+    asMutable(allocated)->owningArena = this;
+
+    return allocated;
+}
+
+TypePackId TypeArena::freshTypePack(Scope* scope)
+{
+    TypePackId allocated = typePacks.allocate(FreeTypePack{scope});
 
     asMutable(allocated)->owningArena = this;
 

Analysis/src/TypeAttach.cpp

@@ -13,8 +13,7 @@
 
 #include <string>
 
-LUAU_FASTFLAG(LuauStoreCSTData2)
+LUAU_FASTFLAG(LuauStoreCSTData)
-LUAU_FASTFLAG(LuauStoreReturnTypesAsPackOnAst)
 
 static char* allocateString(Luau::Allocator& allocator, std::string_view contents)
 {
@@ -220,21 +219,21 @@ public:
         return Luau::visit(*this, mtv.table->ty);
     }
 
-    AstType* operator()(const ExternType& etv)
+    AstType* operator()(const ClassType& ctv)
     {
         RecursionCounter counter(&count);
 
-        char* name = allocateString(*allocator, etv.name);
+        char* name = allocateString(*allocator, ctv.name);
 
-        if (!options.expandExternTypeProps || hasSeen(&etv) || count > 1)
+        if (!options.expandClassProps || hasSeen(&ctv) || count > 1)
             return allocator->alloc<AstTypeReference>(Location(), std::nullopt, AstName{name}, std::nullopt, Location());
 
         AstArray<AstTableProp> props;
-        props.size = etv.props.size();
+        props.size = ctv.props.size();
         props.data = static_cast<AstTableProp*>(allocator->allocate(sizeof(AstTableProp) * props.size));
 
         int idx = 0;
-        for (const auto& [propName, prop] : etv.props)
+        for (const auto& [propName, prop] : ctv.props)
         {
             char* name = allocateString(*allocator, propName);
 
@@ -245,13 +244,13 @@ public:
         }
 
         AstTableIndexer* indexer = nullptr;
-        if (etv.indexer)
+        if (ctv.indexer)
         {
             RecursionCounter counter(&count);
 
             indexer = allocator->alloc<AstTableIndexer>();
-            indexer->indexType = Luau::visit(*this, etv.indexer->indexType->ty);
+            indexer->indexType = Luau::visit(*this, ctv.indexer->indexType->ty);
-            indexer->resultType = Luau::visit(*this, etv.indexer->indexResultType->ty);
+            indexer->resultType = Luau::visit(*this, ctv.indexer->indexResultType->ty);
         }
 
         return allocator->alloc<AstTypeTable>(Location(), props, indexer);
@@ -309,7 +308,7 @@ public:
 
             if (el)
                 new (arg)
-                    std::optional<AstArgumentName>(AstArgumentName(AstName(el->name.c_str()), FFlag::LuauStoreCSTData2 ? Location() : el->location));
+                    std::optional<AstArgumentName>(AstArgumentName(AstName(el->name.c_str()), FFlag::LuauStoreCSTData ? Location() : el->location));
             else
                 new (arg) std::optional<AstArgumentName>();
         }
@@ -329,20 +328,10 @@ public:
         if (retTail)
             retTailAnnotation = rehydrate(*retTail);
 
-        if (FFlag::LuauStoreReturnTypesAsPackOnAst)
-        {
-            auto returnAnnotation = allocator->alloc<AstTypePackExplicit>(Location(), AstTypeList{returnTypes, retTailAnnotation});
-            return allocator->alloc<AstTypeFunction>(
-                Location(), generics, genericPacks, AstTypeList{argTypes, argTailAnnotation}, argNames, returnAnnotation
-            );
-        }
-        else
-        {
         return allocator->alloc<AstTypeFunction>(
             Location(), generics, genericPacks, AstTypeList{argTypes, argTailAnnotation}, argNames, AstTypeList{returnTypes, retTailAnnotation}
         );
     }
-    }
     AstType* operator()(const ErrorType&)
     {
         return allocator->alloc<AstTypeReference>(Location(), std::nullopt, AstName("Unifiable<Error>"), std::nullopt, Location());
@@ -596,8 +585,6 @@ public:
             visitLocal(arg);
         }
 
-        if (FFlag::LuauStoreReturnTypesAsPackOnAst)
-        {
         if (!fn->returnAnnotation)
         {
             if (auto result = getScope(fn->body->location))
@@ -610,26 +597,7 @@ public:
                 if (tail)
                     variadicAnnotation = TypeRehydrationVisitor(allocator, &syntheticNames).rehydrate(*tail);
 
-                    fn->returnAnnotation = allocator->alloc<AstTypePackExplicit>(Location(), AstTypeList{typeAstPack(ret), variadicAnnotation});
+                fn->returnAnnotation = AstTypeList{typeAstPack(ret), variadicAnnotation};
-                }
-            }
-        }
-        else
-        {
-            if (!fn->returnAnnotation_DEPRECATED)
-            {
-                if (auto result = getScope(fn->body->location))
-                {
-                    TypePackId ret = result->returnType;
-
-                    AstTypePack* variadicAnnotation = nullptr;
-                    const auto& [v, tail] = flatten(ret);
-
-                    if (tail)
-                        variadicAnnotation = TypeRehydrationVisitor(allocator, &syntheticNames).rehydrate(*tail);
-
-                    fn->returnAnnotation_DEPRECATED = AstTypeList{typeAstPack(ret), variadicAnnotation};
-                }
             }
         }
 

Analysis/src/TypeChecker2.cpp

@@ -30,11 +30,9 @@
 
 LUAU_FASTFLAG(DebugLuauMagicTypes)
 
+LUAU_FASTFLAG(LuauFreeTypesMustHaveBounds)
 LUAU_FASTFLAGVARIABLE(LuauImproveTypePathsInErrors)
 LUAU_FASTFLAG(LuauUserTypeFunTypecheck)
-LUAU_FASTFLAGVARIABLE(LuauTypeCheckerAcceptNumberConcats)
-LUAU_FASTFLAGVARIABLE(LuauTypeCheckerStricterIndexCheck)
-LUAU_FASTFLAG(LuauStoreReturnTypesAsPackOnAst)
 
 namespace Luau
 {
@@ -662,7 +660,7 @@ void TypeChecker2::visit(AstStat* stat)
         return visit(s);
     else if (auto s = stat->as<AstStatDeclareGlobal>())
         return visit(s);
-    else if (auto s = stat->as<AstStatDeclareExternType>())
+    else if (auto s = stat->as<AstStatDeclareClass>())
         return visit(s);
     else if (auto s = stat->as<AstStatError>())
         return visit(s);
@@ -1222,10 +1220,7 @@ void TypeChecker2::visit(AstStatDeclareFunction* stat)
 {
     visitGenerics(stat->generics, stat->genericPacks);
     visit(stat->params);
-    if (FFlag::LuauStoreReturnTypesAsPackOnAst)
     visit(stat->retTypes);
-    else
-        visit(stat->retTypes_DEPRECATED);
 }
 
 void TypeChecker2::visit(AstStatDeclareGlobal* stat)
@@ -1233,9 +1228,9 @@ void TypeChecker2::visit(AstStatDeclareGlobal* stat)
     visit(stat->type);
 }
 
-void TypeChecker2::visit(AstStatDeclareExternType* stat)
+void TypeChecker2::visit(AstStatDeclareClass* stat)
 {
-    for (const AstDeclaredExternTypeProperty& prop : stat->props)
+    for (const AstDeclaredClassProp& prop : stat->props)
         visit(prop.ty);
 }
 
@@ -1679,12 +1674,12 @@ void TypeChecker2::visit(AstExprIndexExpr* indexExpr, ValueContext context)
     {
         return indexExprMetatableHelper(indexExpr, mt, exprType, indexType);
     }
-    else if (auto cls = get<ExternType>(exprType))
+    else if (auto cls = get<ClassType>(exprType))
     {
         if (cls->indexer)
             testIsSubtype(indexType, cls->indexer->indexType, indexExpr->index->location);
         else
-            reportError(DynamicPropertyLookupOnExternTypesUnsafe{exprType}, indexExpr->location);
+            reportError(DynamicPropertyLookupOnClassesUnsafe{exprType}, indexExpr->location);
     }
     else if (get<UnionType>(exprType) && isOptional(exprType))
     {
@@ -1825,16 +1820,8 @@ void TypeChecker2::visit(AstExprFunction* fn)
     visit(fn->body);
 
     // we need to typecheck the return annotation itself, if it exists.
-    if (FFlag::LuauStoreReturnTypesAsPackOnAst)
-    {
     if (fn->returnAnnotation)
-            visit(fn->returnAnnotation);
+        visit(*fn->returnAnnotation);
-    }
-    else
-    {
-        if (fn->returnAnnotation_DEPRECATED)
-            visit(*fn->returnAnnotation_DEPRECATED);
-    }
 
 
     // If the function type has a function annotation, we need to see if we can suggest an annotation
@@ -2048,7 +2035,7 @@ TypeId TypeChecker2::visit(AstExprBinary* expr, AstNode* overrideKey)
         // If we're working with things that are not tables, the metatable comparisons above are a little excessive
         // It's ok for one type to have a meta table and the other to not. In that case, we should fall back on
         // checking if the intersection of the types is inhabited. If `typesHaveIntersection` failed due to limits,
-        // TODO: Maybe add more checks here (e.g. for functions, extern types, etc)
+        // TODO: Maybe add more checks here (e.g. for functions, classes, etc)
         if (!(get<TableType>(leftType) || get<TableType>(rightType)))
             if (!leftMt.has_value() || !rightMt.has_value())
                 matches = matches || typesHaveIntersection != NormalizationResult::False;
@@ -2113,7 +2100,10 @@ TypeId TypeChecker2::visit(AstExprBinary* expr, AstNode* overrideKey)
                 }
                 else
                 {
-                    expectedRets = module->internalTypes.addTypePack({module->internalTypes.freshType(builtinTypes, scope, TypeLevel{})});
+                    expectedRets = module->internalTypes.addTypePack(
+                        {FFlag::LuauFreeTypesMustHaveBounds ? module->internalTypes.freshType(builtinTypes, scope, TypeLevel{})
+                                                            : module->internalTypes.freshType_DEPRECATED(scope, TypeLevel{})}
+                    );
                 }
 
                 TypeId expectedTy = module->internalTypes.addType(FunctionType(expectedArgs, expectedRets));
@@ -2239,21 +2229,10 @@ TypeId TypeChecker2::visit(AstExprBinary* expr, AstNode* overrideKey)
 
         return builtinTypes->numberType;
     case AstExprBinary::Op::Concat:
-    {
-        if (FFlag::LuauTypeCheckerAcceptNumberConcats)
-        {
-            const TypeId numberOrString = module->internalTypes.addType(UnionType{{builtinTypes->numberType, builtinTypes->stringType}});
-            testIsSubtype(leftType, numberOrString, expr->left->location);
-            testIsSubtype(rightType, numberOrString, expr->right->location);
-        }
-        else
-        {
         testIsSubtype(leftType, builtinTypes->stringType, expr->left->location);
         testIsSubtype(rightType, builtinTypes->stringType, expr->right->location);
-        }
 
         return builtinTypes->stringType;
-    }
     case AstExprBinary::Op::CompareGe:
     case AstExprBinary::Op::CompareGt:
     case AstExprBinary::Op::CompareLe:
@@ -2376,7 +2355,8 @@ TypeId TypeChecker2::flattenPack(TypePackId pack)
         return *fst;
     else if (auto ftp = get<FreeTypePack>(pack))
     {
-        TypeId result = module->internalTypes.freshType(builtinTypes, ftp->scope);
+        TypeId result = FFlag::LuauFreeTypesMustHaveBounds ? module->internalTypes.freshType(builtinTypes, ftp->scope)
+                                                           : module->internalTypes.addType(FreeType{ftp->scope});
         TypePackId freeTail = module->internalTypes.addTypePack(FreeTypePack{ftp->scope});
 
         TypePack* resultPack = emplaceTypePack<TypePack>(asMutable(pack));
@@ -2621,10 +2601,7 @@ void TypeChecker2::visit(AstTypeFunction* ty)
 {
     visitGenerics(ty->generics, ty->genericPacks);
     visit(ty->argTypes);
-    if (FFlag::LuauStoreReturnTypesAsPackOnAst)
     visit(ty->returnTypes);
-    else
-        visit(ty->returnTypes_DEPRECATED);
 }
 
 void TypeChecker2::visit(AstTypeTypeof* ty)
@@ -2948,7 +2925,7 @@ PropertyTypes TypeChecker2::lookupProp(
 
     if (normValid)
     {
-        for (const auto& [ty, _negations] : norm->externTypes.externTypes)
+        for (const auto& [ty, _negations] : norm->classes.classes)
         {
             fetch(ty);
 
@@ -3043,10 +3020,10 @@ void TypeChecker2::checkIndexTypeFromType(
         if (propTypes.foundOneProp())
             reportError(MissingUnionProperty{tableTy, propTypes.missingProp, prop}, location);
         // For class LValues, we don't want to report an extension error,
-        // because extern types come into being with full knowledge of their
+        // because classes come into being with full knowledge of their
         // shape. We instead want to report the unknown property error of
         // the `else` branch.
-        else if (context == ValueContext::LValue && !get<ExternType>(tableTy))
+        else if (context == ValueContext::LValue && !get<ClassType>(tableTy))
         {
             const auto lvPropTypes = lookupProp(norm.get(), prop, ValueContext::RValue, location, astIndexExprType, dummy);
             if (lvPropTypes.foundOneProp() && lvPropTypes.noneMissingProp())
@@ -3056,7 +3033,7 @@ void TypeChecker2::checkIndexTypeFromType(
             else
                 reportError(CannotExtendTable{tableTy, CannotExtendTable::Property, prop}, location);
         }
-        else if (context == ValueContext::RValue && !get<ExternType>(tableTy))
+        else if (context == ValueContext::RValue && !get<ClassType>(tableTy))
         {
             const auto rvPropTypes = lookupProp(norm.get(), prop, ValueContext::LValue, location, astIndexExprType, dummy);
             if (rvPropTypes.foundOneProp() && rvPropTypes.noneMissingProp())
@@ -3109,25 +3086,19 @@ PropertyType TypeChecker2::hasIndexTypeFromType(
                 return {NormalizationResult::True, {tt->indexer->indexResultType}};
         }
 
-        if (FFlag::LuauTypeCheckerStricterIndexCheck)
+
-        {
-            return {NormalizationResult::False, {builtinTypes->unknownType}};
-        }
-        else
-        {
         // if we are in a conditional context, we treat the property as present and `unknown` because
         // we may be _refining_ `tableTy` to include that property. we will want to revisit this a bit
         // in the future once luau has support for exact tables since this only applies when inexact.
         return {inConditional(typeContext) ? NormalizationResult::True : NormalizationResult::False, {builtinTypes->unknownType}};
     }
-    }
+    else if (const ClassType* cls = get<ClassType>(ty))
-    else if (const ExternType* cls = get<ExternType>(ty))
     {
         // If the property doesn't exist on the class, we consult the indexer
         // We need to check if the type of the index expression foo (x[foo])
         // is compatible with the indexer's indexType
         // Construct the intersection and test inhabitedness!
-        if (auto property = lookupExternTypeProp(cls, prop))
+        if (auto property = lookupClassProp(cls, prop))
             return {NormalizationResult::True, context == ValueContext::LValue ? property->writeTy : property->readTy};
         if (cls->indexer)
         {
@@ -3200,17 +3171,17 @@ void TypeChecker2::diagnoseMissingTableKey(UnknownProperty* utk, TypeErrorData&
 
     if (auto ttv = getTableType(utk->table))
         accumulate(ttv->props);
-    else if (auto etv = get<ExternType>(follow(utk->table)))
+    else if (auto ctv = get<ClassType>(follow(utk->table)))
     {
-        while (etv)
+        while (ctv)
         {
-            accumulate(etv->props);
+            accumulate(ctv->props);
 
-            if (!etv->parent)
+            if (!ctv->parent)
                 break;
 
-            etv = get<ExternType>(*etv->parent);
+            ctv = get<ClassType>(*ctv->parent);
-            LUAU_ASSERT(etv);
+            LUAU_ASSERT(ctv);
         }
     }
 

Analysis/src/TypeFunctionReductionGuesser.cpp

@@ -46,7 +46,7 @@ struct InstanceCollector2 : TypeOnceVisitor
             cyclicInstance.insert(t);
     }
 
-    bool visit(TypeId ty, const ExternType&) override
+    bool visit(TypeId ty, const ClassType&) override
     {
         return false;
     }

Analysis/src/TypeFunctionRuntime.cpp

@@ -14,8 +14,8 @@
 #include <vector>
 
 LUAU_DYNAMIC_FASTINT(LuauTypeFunctionSerdeIterationLimit)
+LUAU_FASTFLAGVARIABLE(LuauTypeFunPrintFix)
 LUAU_FASTFLAGVARIABLE(LuauTypeFunReadWriteParents)
-LUAU_FASTFLAGVARIABLE(LuauTypeFunOptional)
 
 namespace Luau
 {
@@ -155,7 +155,7 @@ static std::string getTag(lua_State* L, TypeFunctionTypeId ty)
         return "table";
     else if (get<TypeFunctionFunctionType>(ty))
         return "function";
-    else if (get<TypeFunctionExternType>(ty))
+    else if (get<TypeFunctionClassType>(ty))
         return "class";
     else if (get<TypeFunctionGenericType>(ty))
         return "generic";
@@ -316,38 +316,6 @@ static int getSingletonValue(lua_State* L)
     luaL_error(L, "type.value: can't call `value` method on `%s` type", getTag(L, self).c_str());
 }
 
-// Luau: `types.optional(ty: type) -> type`
-// Returns the type instance representing an optional version of `ty`.
-// If `ty` is a union, this adds `nil` to the components of the union.
-// Otherwise, makes a union of the two things.
-static int createOptional(lua_State* L)
-{
-    LUAU_ASSERT(FFlag::LuauTypeFunOptional);
-
-    int argumentCount = lua_gettop(L);
-    if (argumentCount != 1)
-        luaL_error(L, "types.optional: expected 1 argument, but got %d", argumentCount);
-
-    TypeFunctionTypeId argument = getTypeUserData(L, 1);
-
-    std::vector<TypeFunctionTypeId> components;
-
-    if (auto unionTy = get<TypeFunctionUnionType>(argument))
-    {
-        components.reserve(unionTy->components.size() + 1);
-
-        components.insert(components.begin(), unionTy->components.begin(), unionTy->components.end());
-    }
-    else
-        components.emplace_back(argument);
-
-    components.emplace_back(allocateTypeFunctionType(L, TypeFunctionPrimitiveType(TypeFunctionPrimitiveType::NilType)));
-
-    allocTypeUserData(L, TypeFunctionUnionType{components});
-
-    return 1;
-}
-
 // Luau: `types.unionof(...: type) -> type`
 // Returns the type instance representing union
 static int createUnion(lua_State* L)
@@ -1147,7 +1115,7 @@ static int getClassParent_DEPRECATED(lua_State* L)
         luaL_error(L, "type.parent: expected 1 arguments, but got %d", argumentCount);
 
     TypeFunctionTypeId self = getTypeUserData(L, 1);
-    auto tfct = get<TypeFunctionExternType>(self);
+    auto tfct = get<TypeFunctionClassType>(self);
     if (!tfct)
         luaL_error(L, "type.parent: expected self to be a class, but got %s instead", getTag(L, self).c_str());
 
@@ -1169,7 +1137,7 @@ static int getReadParent(lua_State* L)
         luaL_error(L, "type.parent: expected 1 arguments, but got %d", argumentCount);
 
     TypeFunctionTypeId self = getTypeUserData(L, 1);
-    auto tfct = get<TypeFunctionExternType>(self);
+    auto tfct = get<TypeFunctionClassType>(self);
     if (!tfct)
         luaL_error(L, "type.parent: expected self to be a class, but got %s instead", getTag(L, self).c_str());
 
@@ -1191,7 +1159,7 @@ static int getWriteParent(lua_State* L)
         luaL_error(L, "type.parent: expected 1 arguments, but got %d", argumentCount);
 
     TypeFunctionTypeId self = getTypeUserData(L, 1);
-    auto tfct = get<TypeFunctionExternType>(self);
+    auto tfct = get<TypeFunctionClassType>(self);
     if (!tfct)
         luaL_error(L, "type.parent: expected self to be a class, but got %s instead", getTag(L, self).c_str());
 
@@ -1275,7 +1243,7 @@ static int getProps(lua_State* L)
         return 1;
     }
 
-    if (auto tfct = get<TypeFunctionExternType>(self))
+    if (auto tfct = get<TypeFunctionClassType>(self))
     {
         lua_createtable(L, int(tfct->props.size()), 0);
         for (auto& [name, prop] : tfct->props)
@@ -1338,7 +1306,7 @@ static int getIndexer(lua_State* L)
         return 1;
     }
 
-    if (auto tfct = get<TypeFunctionExternType>(self))
+    if (auto tfct = get<TypeFunctionClassType>(self))
     {
         // if the indexer does not exist, we should return nil
         if (!tfct->indexer.has_value())
@@ -1386,7 +1354,7 @@ static int getReadIndexer(lua_State* L)
         return 1;
     }
 
-    if (auto tfct = get<TypeFunctionExternType>(self))
+    if (auto tfct = get<TypeFunctionClassType>(self))
     {
         // if the indexer does not exist, we should return nil
         if (!tfct->indexer.has_value())
@@ -1432,7 +1400,7 @@ static int getWriteIndexer(lua_State* L)
         return 1;
     }
 
-    if (auto tfct = get<TypeFunctionExternType>(self))
+    if (auto tfct = get<TypeFunctionClassType>(self))
     {
         // if the indexer does not exist, we should return nil
         if (!tfct->indexer.has_value())
@@ -1472,7 +1440,7 @@ static int getMetatable(lua_State* L)
         return 1;
     }
 
-    if (auto tfct = get<TypeFunctionExternType>(self))
+    if (auto tfct = get<TypeFunctionClassType>(self))
     {
         // if the metatable does not exist, we should return nil
         if (!tfct->metatable.has_value())
@@ -1557,7 +1525,6 @@ void registerTypesLibrary(lua_State* L)
         {"copy", deepCopy},
         {"generic", createGeneric},
 
-        {(FFlag::LuauTypeFunOptional) ? "optional" : nullptr, (FFlag::LuauTypeFunOptional) ? createOptional : nullptr},
         {nullptr, nullptr}
     };
 
@@ -1627,7 +1594,7 @@ void registerTypeUserData(lua_State* L)
         // Union and Intersection type methods
         {"components", getComponents},
 
-        //  Extern type methods
+        // Class type methods
         {FFlag::LuauTypeFunReadWriteParents ? "readparent" : "parent", FFlag::LuauTypeFunReadWriteParents ? getReadParent : getClassParent_DEPRECATED},
 
         // Function type methods (cont.)
@@ -1638,7 +1605,7 @@ void registerTypeUserData(lua_State* L)
         {"name", getGenericName},
         {"ispack", getGenericIsPack},
 
-        // move this under extern type methods when removing FFlagLuauTypeFunReadWriteParents
+        // move this under Class type methods when removing FFlagLuauTypeFunReadWriteParents
         {FFlag::LuauTypeFunReadWriteParents ? "writeparent" : nullptr, FFlag::LuauTypeFunReadWriteParents ? getWriteParent : nullptr},
 
         {nullptr, nullptr}
@@ -1689,7 +1656,10 @@ static int print(lua_State* L)
         const char* s = luaL_tolstring(L, i, &l); // convert to string using __tostring et al
         if (i > 1)
         {
+            if (FFlag::LuauTypeFunPrintFix)
                 result.append(1, '\t');
+            else
+                result.append('\t', 1);
         }
         result.append(s, l);
         lua_pop(L, 1);
@@ -1937,12 +1907,12 @@ bool areEqual(SeenSet& seen, const TypeFunctionFunctionType& lhs, const TypeFunc
     return true;
 }
 
-bool areEqual(SeenSet& seen, const TypeFunctionExternType& lhs, const TypeFunctionExternType& rhs)
+bool areEqual(SeenSet& seen, const TypeFunctionClassType& lhs, const TypeFunctionClassType& rhs)
 {
     if (seenSetContains(seen, &lhs, &rhs))
         return true;
 
-    return lhs.externTy == rhs.externTy;
+    return lhs.classTy == rhs.classTy;
 }
 
 bool areEqual(SeenSet& seen, const TypeFunctionType& lhs, const TypeFunctionType& rhs)
@@ -2010,8 +1980,8 @@ bool areEqual(SeenSet& seen, const TypeFunctionType& lhs, const TypeFunctionType
     }
 
     {
-        const TypeFunctionExternType* lf = get<TypeFunctionExternType>(&lhs);
+        const TypeFunctionClassType* lf = get<TypeFunctionClassType>(&lhs);
-        const TypeFunctionExternType* rf = get<TypeFunctionExternType>(&rhs);
+        const TypeFunctionClassType* rf = get<TypeFunctionClassType>(&rhs);
         if (lf && rf)
             return areEqual(seen, *lf, *rf);
     }
@@ -2300,7 +2270,7 @@ private:
             TypeFunctionTypePackId emptyTypePack = typeFunctionRuntime->typePackArena.allocate(TypeFunctionTypePack{});
             target = typeFunctionRuntime->typeArena.allocate(TypeFunctionFunctionType{{}, {}, emptyTypePack, emptyTypePack});
         }
-        else if (auto c = get<TypeFunctionExternType>(ty))
+        else if (auto c = get<TypeFunctionClassType>(ty))
             target = ty; // Don't copy a class since they are immutable
         else if (auto g = get<TypeFunctionGenericType>(ty))
             target = typeFunctionRuntime->typeArena.allocate(TypeFunctionGenericType{g->isNamed, g->isPack, g->name});
@@ -2355,7 +2325,7 @@ private:
             cloneChildren(t1, t2);
         else if (auto [f1, f2] = std::tuple{getMutable<TypeFunctionFunctionType>(ty), getMutable<TypeFunctionFunctionType>(tfti)}; f1 && f2)
             cloneChildren(f1, f2);
-        else if (auto [c1, c2] = std::tuple{getMutable<TypeFunctionExternType>(ty), getMutable<TypeFunctionExternType>(tfti)}; c1 && c2)
+        else if (auto [c1, c2] = std::tuple{getMutable<TypeFunctionClassType>(ty), getMutable<TypeFunctionClassType>(tfti)}; c1 && c2)
             cloneChildren(c1, c2);
         else if (auto [g1, g2] = std::tuple{getMutable<TypeFunctionGenericType>(ty), getMutable<TypeFunctionGenericType>(tfti)}; g1 && g2)
             cloneChildren(g1, g2);
@@ -2465,7 +2435,7 @@ private:
         f2->retTypes = shallowClone(f1->retTypes);
     }
 
-    void cloneChildren(TypeFunctionExternType* c1, TypeFunctionExternType* c2)
+    void cloneChildren(TypeFunctionClassType* c1, TypeFunctionClassType* c2)
     {
         // noop.
     }

Analysis/src/TypeFunctionRuntimeBuilder.cpp

@@ -206,12 +206,12 @@ private:
             TypeFunctionTypePackId emptyTypePack = typeFunctionRuntime->typePackArena.allocate(TypeFunctionTypePack{});
             target = typeFunctionRuntime->typeArena.allocate(TypeFunctionFunctionType{{}, {}, emptyTypePack, emptyTypePack});
         }
-        else if (auto c = get<ExternType>(ty))
+        else if (auto c = get<ClassType>(ty))
         {
             // Since there aren't any new class types being created in type functions, we will deserialize by using a direct reference to the original
             // class
             target = typeFunctionRuntime->typeArena.allocate(
-                TypeFunctionExternType{{}, std::nullopt, std::nullopt, std::nullopt, std::nullopt, std::nullopt, ty}
+                TypeFunctionClassType{{}, std::nullopt, std::nullopt, std::nullopt, std::nullopt, std::nullopt, ty}
             );
         }
         else if (auto g = get<GenericType>(ty))
@@ -291,7 +291,7 @@ private:
             serializeChildren(m1, m2);
         else if (auto [f1, f2] = std::tuple{get<FunctionType>(ty), getMutable<TypeFunctionFunctionType>(tfti)}; f1 && f2)
             serializeChildren(f1, f2);
-        else if (auto [c1, c2] = std::tuple{get<ExternType>(ty), getMutable<TypeFunctionExternType>(tfti)}; c1 && c2)
+        else if (auto [c1, c2] = std::tuple{get<ClassType>(ty), getMutable<TypeFunctionClassType>(tfti)}; c1 && c2)
             serializeChildren(c1, c2);
         else if (auto [g1, g2] = std::tuple{get<GenericType>(ty), getMutable<TypeFunctionGenericType>(tfti)}; g1 && g2)
             serializeChildren(g1, g2);
@@ -411,7 +411,7 @@ private:
         f2->retTypes = shallowSerialize(f1->retTypes);
     }
 
-    void serializeChildren(const ExternType* c1, TypeFunctionExternType* c2)
+    void serializeChildren(const ClassType* c1, TypeFunctionClassType* c2)
     {
         for (const auto& [k, p] : c1->props)
         {
@@ -702,9 +702,9 @@ private:
             TypePackId emptyTypePack = state->ctx->arena->addTypePack(TypePack{});
             target = state->ctx->arena->addType(FunctionType{emptyTypePack, emptyTypePack, {}, false});
         }
-        else if (auto c = get<TypeFunctionExternType>(ty))
+        else if (auto c = get<TypeFunctionClassType>(ty))
         {
-            target = c->externTy;
+            target = c->classTy;
         }
         else if (auto g = get<TypeFunctionGenericType>(ty))
         {
@@ -811,7 +811,7 @@ private:
             deserializeChildren(m2, m1);
         else if (auto [f1, f2] = std::tuple{getMutable<FunctionType>(ty), getMutable<TypeFunctionFunctionType>(tfti)}; f1 && f2)
             deserializeChildren(f2, f1);
-        else if (auto [c1, c2] = std::tuple{getMutable<ExternType>(ty), getMutable<TypeFunctionExternType>(tfti)}; c1 && c2)
+        else if (auto [c1, c2] = std::tuple{getMutable<ClassType>(ty), getMutable<TypeFunctionClassType>(tfti)}; c1 && c2)
             deserializeChildren(c2, c1);
         else if (auto [g1, g2] = std::tuple{getMutable<GenericType>(ty), getMutable<TypeFunctionGenericType>(tfti)}; g1 && g2)
             deserializeChildren(g2, g1);
@@ -972,7 +972,7 @@ private:
             f1->retTypes = shallowDeserialize(f2->retTypes);
     }
 
-    void deserializeChildren(TypeFunctionExternType* c2, ExternType* c1)
+    void deserializeChildren(TypeFunctionClassType* c2, ClassType* c1)
     {
         // noop.
     }

Analysis/src/TypeInfer.cpp

@@ -32,19 +32,17 @@ LUAU_FASTINTVARIABLE(LuauVisitRecursionLimit, 500)
 LUAU_FASTFLAG(LuauKnowsTheDataModel3)
 LUAU_FASTFLAGVARIABLE(DebugLuauFreezeDuringUnification)
 LUAU_FASTFLAG(LuauInstantiateInSubtyping)
-LUAU_FASTFLAG(LuauStoreReturnTypesAsPackOnAst)
+LUAU_FASTFLAG(LuauPreserveUnionIntersectionNodeForLeadingTokenSingleType)
+LUAU_FASTFLAG(LuauFreeTypesMustHaveBounds)
 
-LUAU_FASTFLAG(LuauRetainDefinitionAliasLocations)
+LUAU_FASTFLAG(LuauModuleHoldsAstRoot)
-LUAU_FASTFLAGVARIABLE(LuauStatForInFix)
-LUAU_FASTFLAGVARIABLE(LuauReduceCheckBinaryExprStackPressure)
-LUAU_FASTFLAGVARIABLE(LuauLimitIterationWhenCheckingArgumentCounts)
 
 namespace Luau
 {
 
 static bool typeCouldHaveMetatable(TypeId ty)
 {
-    return get<TableType>(follow(ty)) || get<ExternType>(follow(ty)) || get<MetatableType>(follow(ty));
+    return get<TableType>(follow(ty)) || get<ClassType>(follow(ty)) || get<MetatableType>(follow(ty));
 }
 
 static void defaultLuauPrintLine(const std::string& s)
@@ -258,6 +256,7 @@ ModulePtr TypeChecker::checkWithoutRecursionCheck(const SourceModule& module, Mo
     currentModule->type = module.type;
     currentModule->allocator = module.allocator;
     currentModule->names = module.names;
+    if (FFlag::LuauModuleHoldsAstRoot)
         currentModule->root = module.root;
 
     iceHandler->moduleName = module.name;
@@ -318,7 +317,7 @@ ModulePtr TypeChecker::checkWithoutRecursionCheck(const SourceModule& module, Mo
     unifierState.skipCacheForType.clear();
 
     duplicateTypeAliases.clear();
-    incorrectExternTypeDefinitions.clear();
+    incorrectClassDefinitions.clear();
 
     return std::move(currentModule);
 }
@@ -383,7 +382,7 @@ ControlFlow TypeChecker::check(const ScopePtr& scope, const AstStat& program)
     }
     else if (auto global = program.as<AstStatDeclareFunction>())
         return check(scope, *global);
-    else if (auto global = program.as<AstStatDeclareExternType>())
+    else if (auto global = program.as<AstStatDeclareClass>())
         return check(scope, *global);
     else if (auto errorStatement = program.as<AstStatError>())
     {
@@ -498,9 +497,9 @@ ControlFlow TypeChecker::checkBlockWithoutRecursionCheck(const ScopePtr& scope,
             prototype(scope, *typealias, subLevel);
             ++subLevel;
         }
-        else if (const auto& declaredExternType = stat->as<AstStatDeclareExternType>())
+        else if (const auto& declaredClass = stat->as<AstStatDeclareClass>())
         {
-            prototype(scope, *declaredExternType);
+            prototype(scope, *declaredClass);
         }
     }
 
@@ -788,7 +787,7 @@ struct Demoter : Substitution
 
     bool ignoreChildren(TypeId ty) override
     {
-        if (get<ExternType>(ty))
+        if (get<ClassType>(ty))
             return true;
 
         return false;
@@ -798,7 +797,8 @@ struct Demoter : Substitution
     {
         auto ftv = get<FreeType>(ty);
         LUAU_ASSERT(ftv);
-        return arena->freshType(builtins, demotedLevel(ftv->level));
+        return FFlag::LuauFreeTypesMustHaveBounds ? arena->freshType(builtins, demotedLevel(ftv->level))
+                                                  : addType(FreeType{demotedLevel(ftv->level)});
     }
 
     TypePackId clean(TypePackId tp) override
@@ -1319,26 +1319,10 @@ ControlFlow TypeChecker::check(const ScopePtr& scope, const AstStatForIn& forin)
             // Extract the remaining return values of the call
             // and check them against the parameter types of the iterator function.
             auto [types, tail] = flatten(callRetPack);
-
-            if (FFlag::LuauStatForInFix)
-            {
-                if (!types.empty())
-                {
             std::vector<TypeId> argTypes = std::vector<TypeId>(types.begin() + 1, types.end());
             argPack = addTypePack(TypePackVar{TypePack{std::move(argTypes), tail}});
         }
         else
-                {
-                    argPack = addTypePack(TypePack{});
-                }
-            }
-            else
-            {
-                std::vector<TypeId> argTypes = std::vector<TypeId>(types.begin() + 1, types.end());
-                argPack = addTypePack(TypePackVar{TypePack{std::move(argTypes), tail}});
-            }
-        }
-        else
         {
             // Check if iterator function accepts 0 arguments
             argPack = addTypePack(TypePack{});
@@ -1674,9 +1658,6 @@ void TypeChecker::prototype(const ScopePtr& scope, const AstStatTypeAlias& typea
             FreeType* ftv = getMutable<FreeType>(ty);
             LUAU_ASSERT(ftv);
             ftv->forwardedTypeAlias = true;
-            if (FFlag::LuauRetainDefinitionAliasLocations)
-                bindingsMap[name] = {std::move(generics), std::move(genericPacks), ty, typealias.location};
-            else
             bindingsMap[name] = {std::move(generics), std::move(genericPacks), ty};
 
             scope->typeAliasLocations[name] = typealias.location;
@@ -1685,82 +1666,79 @@ void TypeChecker::prototype(const ScopePtr& scope, const AstStatTypeAlias& typea
     }
 }
 
-void TypeChecker::prototype(const ScopePtr& scope, const AstStatDeclareExternType& declaredExternType)
+void TypeChecker::prototype(const ScopePtr& scope, const AstStatDeclareClass& declaredClass)
 {
-    std::optional<TypeId> superTy = std::make_optional(builtinTypes->externType);
+    std::optional<TypeId> superTy = std::make_optional(builtinTypes->classType);
-    if (declaredExternType.superName)
+    if (declaredClass.superName)
     {
-        Name superName = Name(declaredExternType.superName->value);
+        Name superName = Name(declaredClass.superName->value);
         std::optional<TypeFun> lookupType = scope->lookupType(superName);
 
         if (!lookupType)
         {
-            reportError(declaredExternType.location, UnknownSymbol{superName, UnknownSymbol::Type});
+            reportError(declaredClass.location, UnknownSymbol{superName, UnknownSymbol::Type});
-            incorrectExternTypeDefinitions.insert(&declaredExternType);
+            incorrectClassDefinitions.insert(&declaredClass);
             return;
         }
 
-        // We don't have generic extern types, so this assertion _should_ never be hit.
+        // We don't have generic classes, so this assertion _should_ never be hit.
         LUAU_ASSERT(lookupType->typeParams.size() == 0 && lookupType->typePackParams.size() == 0);
         superTy = lookupType->type;
 
-        if (!get<ExternType>(follow(*superTy)))
+        if (!get<ClassType>(follow(*superTy)))
         {
             reportError(
-                declaredExternType.location,
+                declaredClass.location,
-                GenericError{format("Cannot use non-class type '%s' as a superclass of class '%s'", superName.c_str(), declaredExternType.name.value)}
+                GenericError{format("Cannot use non-class type '%s' as a superclass of class '%s'", superName.c_str(), declaredClass.name.value)}
             );
-            incorrectExternTypeDefinitions.insert(&declaredExternType);
+            incorrectClassDefinitions.insert(&declaredClass);
             return;
         }
     }
 
-    Name className(declaredExternType.name.value);
+    Name className(declaredClass.name.value);
 
-    TypeId classTy = addType(ExternType(className, {}, superTy, std::nullopt, {}, {}, currentModule->name, declaredExternType.location));
+    TypeId classTy = addType(ClassType(className, {}, superTy, std::nullopt, {}, {}, currentModule->name, declaredClass.location));
-    ExternType* etv = getMutable<ExternType>(classTy);
+    ClassType* ctv = getMutable<ClassType>(classTy);
     TypeId metaTy = addType(TableType{TableState::Sealed, scope->level});
 
-    etv->metatable = metaTy;
+    ctv->metatable = metaTy;
-    if (FFlag::LuauRetainDefinitionAliasLocations)
-        scope->exportedTypeBindings[className] = TypeFun{{}, classTy, declaredExternType.location};
-    else
     scope->exportedTypeBindings[className] = TypeFun{{}, classTy};
 }
 
-ControlFlow TypeChecker::check(const ScopePtr& scope, const AstStatDeclareExternType& declaredExternType)
+ControlFlow TypeChecker::check(const ScopePtr& scope, const AstStatDeclareClass& declaredClass)
 {
-    Name className(declaredExternType.name.value);
+    Name className(declaredClass.name.value);
 
     // Don't bother checking if the class definition was incorrect
-    if (incorrectExternTypeDefinitions.find(&declaredExternType))
+    if (incorrectClassDefinitions.find(&declaredClass))
         return ControlFlow::None;
 
     std::optional<TypeFun> binding;
     if (auto it = scope->exportedTypeBindings.find(className); it != scope->exportedTypeBindings.end())
         binding = it->second;
 
-    // This extern type definition must have been `prototype()`d first.
+    // This class definition must have been `prototype()`d first.
     if (!binding)
-        ice("Extern type not predeclared");
+        ice("Class not predeclared");
 
-    TypeId externTy = binding->type;
+    TypeId classTy = binding->type;
-    ExternType* etv = getMutable<ExternType>(externTy);
+    ClassType* ctv = getMutable<ClassType>(classTy);
 
-    if (!etv->metatable)
+    if (!ctv->metatable)
-        ice("No metatable for declared extern type");
+        ice("No metatable for declared class");
 
-    if (const auto& indexer = declaredExternType.indexer)
+    if (const auto& indexer = declaredClass.indexer)
-        etv->indexer = TableIndexer(resolveType(scope, *indexer->indexType), resolveType(scope, *indexer->resultType));
+        ctv->indexer = TableIndexer(resolveType(scope, *indexer->indexType), resolveType(scope, *indexer->resultType));
 
-    TableType* metatable = getMutable<TableType>(*etv->metatable);
+    TableType* metatable = getMutable<TableType>(*ctv->metatable);
-    for (const AstDeclaredExternTypeProperty& prop : declaredExternType.props)
+    for (const AstDeclaredClassProp& prop : declaredClass.props)
     {
         Name propName(prop.name.value);
         TypeId propTy = resolveType(scope, *prop.ty);
 
         bool assignToMetatable = isMetamethod(propName);
-        Luau::ExternType::Props& assignTo = assignToMetatable ? metatable->props : etv->props;
+        Luau::ClassType::Props& assignTo = assignToMetatable ? metatable->props : ctv->props;
 
         // Function types always take 'self', but this isn't reflected in the
         // parsed annotation. Add it here.
@@ -1769,7 +1747,7 @@ ControlFlow TypeChecker::check(const ScopePtr& scope, const AstStatDeclareExtern
             if (FunctionType* ftv = getMutable<FunctionType>(propTy))
             {
                 ftv->argNames.insert(ftv->argNames.begin(), FunctionArgument{"self", {}});
-                ftv->argTypes = addTypePack(TypePack{{externTy}, ftv->argTypes});
+                ftv->argTypes = addTypePack(TypePack{{classTy}, ftv->argTypes});
                 ftv->hasSelf = true;
 
                 FunctionDefinition defn;
@@ -1812,7 +1790,7 @@ ControlFlow TypeChecker::check(const ScopePtr& scope, const AstStatDeclareExtern
             }
             else
             {
-                reportError(declaredExternType.location, GenericError{format("Cannot overload non-function class member '%s'", propName.c_str())});
+                reportError(declaredClass.location, GenericError{format("Cannot overload non-function class member '%s'", propName.c_str())});
             }
         }
     }
@@ -1851,8 +1829,7 @@ ControlFlow TypeChecker::check(const ScopePtr& scope, const AstStatDeclareFuncti
     );
 
     TypePackId argPack = resolveTypePack(funScope, global.params);
-    TypePackId retPack =
+    TypePackId retPack = resolveTypePack(funScope, global.retTypes);
-        FFlag::LuauStoreReturnTypesAsPackOnAst ? resolveTypePack(funScope, *global.retTypes) : resolveTypePack(funScope, global.retTypes_DEPRECATED);
 
     FunctionDefinition defn;
 
@@ -1926,7 +1903,7 @@ WithPredicate<TypeId> TypeChecker::checkExpr(const ScopePtr& scope, const AstExp
     else if (auto a = expr.as<AstExprUnary>())
         result = checkExpr(scope, *a);
     else if (auto a = expr.as<AstExprBinary>())
-        result = FFlag::LuauReduceCheckBinaryExprStackPressure ? checkExpr(scope, *a, expectedType) : checkExpr_DEPRECATED(scope, *a, expectedType);
+        result = checkExpr(scope, *a, expectedType);
     else if (auto a = expr.as<AstExprTypeAssertion>())
         result = checkExpr(scope, *a);
     else if (auto a = expr.as<AstExprError>())
@@ -2137,9 +2114,9 @@ std::optional<TypeId> TypeChecker::getIndexTypeFromTypeImpl(
         if (auto found = findTablePropertyRespectingMeta(type, name, location, addErrors))
             return *found;
     }
-    else if (const ExternType* cls = get<ExternType>(type))
+    else if (const ClassType* cls = get<ClassType>(type))
     {
-        const Property* prop = lookupExternTypeProp(cls, name);
+        const Property* prop = lookupClassProp(cls, name);
         if (prop)
             return prop->type();
 
@@ -3188,9 +3165,6 @@ WithPredicate<TypeId> TypeChecker::checkExpr(const ScopePtr& scope, const AstExp
         return {result, {OrPredicate{std::move(lhsPredicates), std::move(rhsPredicates)}}};
     }
     else if (expr.op == AstExprBinary::CompareEq || expr.op == AstExprBinary::CompareNe)
-    {
-        // Defer the stack allocation of lhs, predicate etc until this lambda is called.
-        auto checkExprOr = [&]() -> WithPredicate<TypeId>
     {
         // For these, passing expectedType is worse than simply forcing them, because their implementation
         // may inadvertently check if expectedTypes exist first and use it, instead of forceSingleton first.
@@ -3202,68 +3176,9 @@ WithPredicate<TypeId> TypeChecker::checkExpr(const ScopePtr& scope, const AstExp
 
         PredicateVec predicates;
 
-            if (auto lvalue = tryGetLValue(*expr.left))
-                predicates.emplace_back(EqPredicate{std::move(*lvalue), rhs.type, expr.location});
-
-            if (auto lvalue = tryGetLValue(*expr.right))
-                predicates.emplace_back(EqPredicate{std::move(*lvalue), lhs.type, expr.location});
-
-            if (!predicates.empty() && expr.op == AstExprBinary::CompareNe)
-                predicates = {NotPredicate{std::move(predicates)}};
-
-            return {checkBinaryOperation(scope, expr, lhs.type, rhs.type), std::move(predicates)};
-        };
-        return checkExprOr();
-    }
-    else
-    {
-        // Expected types are not useful for other binary operators.
-        WithPredicate<TypeId> lhs = checkExpr(scope, *expr.left);
-        WithPredicate<TypeId> rhs = checkExpr(scope, *expr.right);
-
-        // Intentionally discarding predicates with other operators.
-        return WithPredicate{checkBinaryOperation(scope, expr, lhs.type, rhs.type, lhs.predicates)};
-    }
-}
-
-WithPredicate<TypeId> TypeChecker::checkExpr_DEPRECATED(const ScopePtr& scope, const AstExprBinary& expr, std::optional<TypeId> expectedType)
-{
-    if (expr.op == AstExprBinary::And)
-    {
-        auto [lhsTy, lhsPredicates] = checkExpr(scope, *expr.left, expectedType);
-
-        ScopePtr innerScope = childScope(scope, expr.location);
-        resolve(lhsPredicates, innerScope, true);
-
-        auto [rhsTy, rhsPredicates] = checkExpr(innerScope, *expr.right, expectedType);
-
-        return {checkBinaryOperation(scope, expr, lhsTy, rhsTy), {AndPredicate{std::move(lhsPredicates), std::move(rhsPredicates)}}};
-    }
-    else if (expr.op == AstExprBinary::Or)
-    {
-        auto [lhsTy, lhsPredicates] = checkExpr(scope, *expr.left, expectedType);
-
-        ScopePtr innerScope = childScope(scope, expr.location);
-        resolve(lhsPredicates, innerScope, false);
-
-        auto [rhsTy, rhsPredicates] = checkExpr(innerScope, *expr.right, expectedType);
-
-        // Because of C++, I'm not sure if lhsPredicates was not moved out by the time we call checkBinaryOperation.
-        TypeId result = checkBinaryOperation(scope, expr, lhsTy, rhsTy, lhsPredicates);
-        return {result, {OrPredicate{std::move(lhsPredicates), std::move(rhsPredicates)}}};
-    }
-    else if (expr.op == AstExprBinary::CompareEq || expr.op == AstExprBinary::CompareNe)
-    {
-        // For these, passing expectedType is worse than simply forcing them, because their implementation
-        // may inadvertently check if expectedTypes exist first and use it, instead of forceSingleton first.
-        WithPredicate<TypeId> lhs = checkExpr(scope, *expr.left, std::nullopt, /*forceSingleton=*/true);
-        WithPredicate<TypeId> rhs = checkExpr(scope, *expr.right, std::nullopt, /*forceSingleton=*/true);
-        if (auto predicate = tryGetTypeGuardPredicate(expr))
-            return {booleanType, {std::move(*predicate)}};
-
-        PredicateVec predicates;
         if (auto lvalue = tryGetLValue(*expr.left))
             predicates.push_back(EqPredicate{std::move(*lvalue), rhs.type, expr.location});
+
         if (auto lvalue = tryGetLValue(*expr.right))
             predicates.push_back(EqPredicate{std::move(*lvalue), lhs.type, expr.location});
 
@@ -3462,14 +3377,14 @@ TypeId TypeChecker::checkLValueBinding(const ScopePtr& scope, const AstExprIndex
             return errorRecoveryType(scope);
         }
     }
-    else if (const ExternType* lhsExternType = get<ExternType>(lhs))
+    else if (const ClassType* lhsClass = get<ClassType>(lhs))
     {
-        if (const Property* prop = lookupExternTypeProp(lhsExternType, name))
+        if (const Property* prop = lookupClassProp(lhsClass, name))
         {
             return prop->type();
         }
 
-        if (auto indexer = lhsExternType->indexer)
+        if (auto indexer = lhsClass->indexer)
         {
             Unifier state = mkUnifier(scope, expr.location);
             state.tryUnify(stringType, indexer->indexType);
@@ -3521,14 +3436,14 @@ TypeId TypeChecker::checkLValueBinding(const ScopePtr& scope, const AstExprIndex
 
     if (value)
     {
-        if (const ExternType* exprExternType = get<ExternType>(exprType))
+        if (const ClassType* exprClass = get<ClassType>(exprType))
         {
-            if (const Property* prop = lookupExternTypeProp(exprExternType, value->value.data))
+            if (const Property* prop = lookupClassProp(exprClass, value->value.data))
             {
                 return prop->type();
             }
 
-            if (auto indexer = exprExternType->indexer)
+            if (auto indexer = exprClass->indexer)
             {
                 unify(stringType, indexer->indexType, scope, expr.index->location);
                 return indexer->indexResultType;
@@ -3554,20 +3469,20 @@ TypeId TypeChecker::checkLValueBinding(const ScopePtr& scope, const AstExprIndex
     }
     else
     {
-        if (const ExternType* exprExternType = get<ExternType>(exprType))
+        if (const ClassType* exprClass = get<ClassType>(exprType))
         {
-            if (auto indexer = exprExternType->indexer)
+            if (auto indexer = exprClass->indexer)
             {
                 unify(indexType, indexer->indexType, scope, expr.index->location);
                 return indexer->indexResultType;
             }
         }
 
-        if (const ExternType* exprExternType = get<ExternType>(exprType))
+        if (const ClassType* exprClass = get<ClassType>(exprType))
         {
             if (isNonstrictMode())
                 return unknownType;
-            reportError(TypeError{expr.location, DynamicPropertyLookupOnExternTypesUnsafe{exprType}});
+            reportError(TypeError{expr.location, DynamicPropertyLookupOnClassesUnsafe{exprType}});
             return errorRecoveryType(scope);
         }
     }
@@ -3848,10 +3763,8 @@ std::pair<TypeId, ScopePtr> TypeChecker::checkFunctionSignature(
     auto [generics, genericPacks] = createGenericTypes(funScope, std::nullopt, expr, expr.generics, expr.genericPacks);
 
     TypePackId retPack;
-    if (FFlag::LuauStoreReturnTypesAsPackOnAst && expr.returnAnnotation)
+    if (expr.returnAnnotation)
         retPack = resolveTypePack(funScope, *expr.returnAnnotation);
-    else if (!FFlag::LuauStoreReturnTypesAsPackOnAst && expr.returnAnnotation_DEPRECATED)
-        retPack = resolveTypePack(funScope, *expr.returnAnnotation_DEPRECATED);
     else if (isNonstrictMode())
         retPack = anyTypePack;
     else if (expectedFunctionType && expectedFunctionType->generics.empty() && expectedFunctionType->genericPacks.empty())
@@ -4058,8 +3971,7 @@ void TypeChecker::checkFunctionBody(const ScopePtr& scope, TypeId ty, const AstE
             // If we're in nonstrict mode we want to only report this missing return
             // statement if there are type annotations on the function. In strict mode
             // we report it regardless.
-            if (!isNonstrictMode() ||
+            if (!isNonstrictMode() || function.returnAnnotation)
-                (FFlag::LuauStoreReturnTypesAsPackOnAst ? function.returnAnnotation != nullptr : function.returnAnnotation_DEPRECATED.has_value()))
             {
                 reportError(getEndLocation(function), FunctionExitsWithoutReturning{funTy->retTypes});
             }
@@ -4117,23 +4029,6 @@ void TypeChecker::checkArgumentList(
 
     size_t paramIndex = 0;
 
-    int loopCount = 0;
-    auto exceedsLoopCount = [&]()
-    {
-        if (FFlag::LuauLimitIterationWhenCheckingArgumentCounts)
-        {
-            ++loopCount;
-            if (loopCount > FInt::LuauTypeInferTypePackLoopLimit)
-            {
-                state.reportError(TypeError{state.location, CodeTooComplex{}});
-                reportErrorCodeTooComplex(state.location);
-                return true;
-            }
-        }
-
-        return false;
-    };
-
     auto reportCountMismatchError = [&state, &argLocations, paramPack, argPack, &funName]()
     {
         // For this case, we want the error span to cover every errant extra parameter
@@ -4208,17 +4103,12 @@ void TypeChecker::checkArgumentList(
                 }
                 else if (auto vtp = state.log.getMutable<VariadicTypePack>(tail))
                 {
-                    loopCount = 0;
-
                     // Function is variadic and requires that all subsequent parameters
                     // be compatible with a type.
                     while (paramIter != endIter)
                     {
                         state.tryUnify(vtp->ty, *paramIter);
                         ++paramIter;
-
-                        if (exceedsLoopCount())
-                            return;
                     }
 
                     return;
@@ -4227,16 +4117,10 @@ void TypeChecker::checkArgumentList(
                 {
                     std::vector<TypeId> rest;
                     rest.reserve(std::distance(paramIter, endIter));
-
-                    loopCount = 0;
-
                     while (paramIter != endIter)
                     {
                         rest.push_back(*paramIter);
                         ++paramIter;
-
-                        if (exceedsLoopCount())
-                            return;
                     }
 
                     TypePackId varPack = addTypePack(TypePackVar{TypePack{rest, paramIter.tail()}});
@@ -4280,17 +4164,12 @@ void TypeChecker::checkArgumentList(
             // too many parameters passed
             if (!paramIter.tail())
             {
-                loopCount = 0;
-
                 while (argIter != endIter)
                 {
                     // The use of unify here is deliberate. We don't want this unification
                     // to be undoable.
                     unify(errorRecoveryType(scope), *argIter, scope, state.location);
                     ++argIter;
-
-                    if (exceedsLoopCount())
-                        return;
                 }
                 reportCountMismatchError();
                 return;
@@ -4304,8 +4183,6 @@ void TypeChecker::checkArgumentList(
             }
             else if (auto vtp = state.log.getMutable<VariadicTypePack>(tail))
             {
-                loopCount = 0;
-
                 // Function is variadic and requires that all subsequent parameters
                 // be compatible with a type.
                 size_t argIndex = paramIndex;
@@ -4321,17 +4198,12 @@ void TypeChecker::checkArgumentList(
 
                     ++argIter;
                     ++argIndex;
-
-                    if (exceedsLoopCount())
-                        return;
                 }
 
                 return;
             }
             else if (state.log.getMutable<FreeTypePack>(tail))
             {
-                loopCount = 0;
-
                 // Create a type pack out of the remaining argument types
                 // and unify it with the tail.
                 std::vector<TypeId> rest;
@@ -4340,9 +4212,6 @@ void TypeChecker::checkArgumentList(
                 {
                     rest.push_back(*argIter);
                     ++argIter;
-
-                    if (exceedsLoopCount())
-                        return;
                 }
 
                 TypePackId varPack = addTypePack(TypePackVar{TypePack{rest, argIter.tail()}});
@@ -4614,9 +4483,9 @@ std::unique_ptr<WithPredicate<TypePackId>> TypeChecker::checkCallOverload(
     {
         callTy = getIndexTypeFromType(scope, mttv->metatable, "__call", expr.func->location, /* addErrors= */ false);
     }
-    else if (const ExternType* etv = get<ExternType>(fn); etv && etv->metatable)
+    else if (const ClassType* ctv = get<ClassType>(fn); ctv && ctv->metatable)
     {
-        callTy = getIndexTypeFromType(scope, *etv->metatable, "__call", expr.func->location, /* addErrors= */ false);
+        callTy = getIndexTypeFromType(scope, *ctv->metatable, "__call", expr.func->location, /* addErrors= */ false);
     }
 
     if (callTy)
@@ -5319,17 +5188,17 @@ void TypeChecker::diagnoseMissingTableKey(UnknownProperty* utk, TypeErrorData& d
 
     if (auto ttv = getTableType(utk->table))
         accumulate(ttv->props);
-    else if (auto etv = get<ExternType>(follow(utk->table)))
+    else if (auto ctv = get<ClassType>(follow(utk->table)))
     {
-        while (etv)
+        while (ctv)
         {
-            accumulate(etv->props);
+            accumulate(ctv->props);
 
-            if (!etv->parent)
+            if (!ctv->parent)
                 break;
 
-            etv = get<ExternType>(*etv->parent);
+            ctv = get<ClassType>(*ctv->parent);
-            LUAU_ASSERT(etv);
+            LUAU_ASSERT(ctv);
         }
     }
 
@@ -5408,7 +5277,8 @@ TypeId TypeChecker::freshType(const ScopePtr& scope)
 
 TypeId TypeChecker::freshType(TypeLevel level)
 {
-    return currentModule->internalTypes.freshType(builtinTypes, level);
+    return FFlag::LuauFreeTypesMustHaveBounds ? currentModule->internalTypes.freshType(builtinTypes, level)
+                                              : currentModule->internalTypes.addType(Type(FreeType(level)));
 }
 
 TypeId TypeChecker::singletonType(bool value)
@@ -5805,8 +5675,7 @@ TypeId TypeChecker::resolveTypeWorker(const ScopePtr& scope, const AstType& anno
         auto [generics, genericPacks] = createGenericTypes(funcScope, std::nullopt, annotation, func->generics, func->genericPacks);
 
         TypePackId argTypes = resolveTypePack(funcScope, func->argTypes);
-        TypePackId retTypes = FFlag::LuauStoreReturnTypesAsPackOnAst ? resolveTypePack(funcScope, *func->returnTypes)
+        TypePackId retTypes = resolveTypePack(funcScope, func->returnTypes);
-                                                                     : resolveTypePack(funcScope, func->returnTypes_DEPRECATED);
 
         std::vector<TypeId> genericTys;
         genericTys.reserve(generics.size());
@@ -5857,9 +5726,13 @@ TypeId TypeChecker::resolveTypeWorker(const ScopePtr& scope, const AstType& anno
         return builtinTypes->nilType;
     }
     else if (const auto& un = annotation.as<AstTypeUnion>())
+    {
+        if (FFlag::LuauPreserveUnionIntersectionNodeForLeadingTokenSingleType)
         {
             if (un->types.size == 1)
                 return resolveType(scope, *un->types.data[0]);
+        }
+
         std::vector<TypeId> types;
         for (AstType* ann : un->types)
             types.push_back(resolveType(scope, *ann));
@@ -5867,9 +5740,13 @@ TypeId TypeChecker::resolveTypeWorker(const ScopePtr& scope, const AstType& anno
         return addType(UnionType{types});
     }
     else if (const auto& un = annotation.as<AstTypeIntersection>())
+    {
+        if (FFlag::LuauPreserveUnionIntersectionNodeForLeadingTokenSingleType)
         {
             if (un->types.size == 1)
                 return resolveType(scope, *un->types.data[0]);
+        }
+
         std::vector<TypeId> types;
         for (AstType* ann : un->types)
             types.push_back(resolveType(scope, *ann));
@@ -6476,7 +6353,7 @@ void TypeChecker::resolve(const TypeGuardPredicate& typeguardP, RefinementMap& r
         return refine(
             [](TypeId ty) -> bool
             {
-                return get<ExternType>(ty);
+                return get<ClassType>(ty);
             }
         );
     }
@@ -6491,13 +6368,13 @@ void TypeChecker::resolve(const TypeGuardPredicate& typeguardP, RefinementMap& r
     TypeId type = follow(typeFun->type);
 
     // You cannot refine to the top class type.
-    if (type == builtinTypes->externType)
+    if (type == builtinTypes->classType)
     {
         return addRefinement(refis, typeguardP.lvalue, errorRecoveryType(scope));
     }
 
-    // We're only interested in the root type of any extern type.
+    // We're only interested in the root class of any classes.
-    if (auto etv = get<ExternType>(type); !etv || (etv->parent != builtinTypes->externType && !hasTag(type, kTypeofRootTag)))
+    if (auto ctv = get<ClassType>(type); !ctv || (ctv->parent != builtinTypes->classType && !hasTag(type, kTypeofRootTag)))
         return addRefinement(refis, typeguardP.lvalue, errorRecoveryType(scope));
 
     // This probably hints at breaking out type filtering functions from the predicate solver so that typeof is not tightly coupled with IsA.

Analysis/src/TypePack.cpp

@@ -6,7 +6,7 @@
 
 #include <stdexcept>
 
-LUAU_FASTFLAGVARIABLE(LuauTypePackDetectCycles)
+LUAU_FASTFLAG(LuauSolverV2);
 
 namespace Luau
 {
@@ -18,11 +18,10 @@ FreeTypePack::FreeTypePack(TypeLevel level)
 {
 }
 
-FreeTypePack::FreeTypePack(Scope* scope, Polarity polarity)
+FreeTypePack::FreeTypePack(Scope* scope)
     : index(Unifiable::freshIndex())
     , level{}
     , scope(scope)
-    , polarity(polarity)
 {
 }
 
@@ -53,10 +52,9 @@ GenericTypePack::GenericTypePack(const Name& name)
 {
 }
 
-GenericTypePack::GenericTypePack(Scope* scope, Polarity polarity)
+GenericTypePack::GenericTypePack(Scope* scope)
     : index(Unifiable::freshIndex())
     , scope(scope)
-    , polarity(polarity)
 {
 }
 
@@ -149,15 +147,6 @@ TypePackIterator& TypePackIterator::operator++()
         currentTypePack = tp->tail ? log->follow(*tp->tail) : nullptr;
         tp = currentTypePack ? log->getMutable<TypePack>(currentTypePack) : nullptr;
 
-        if (FFlag::LuauTypePackDetectCycles && tp)
-        {
-            // Step twice on each iteration to detect cycles
-            tailCycleCheck = tp->tail ? log->follow(*tp->tail) : nullptr;
-
-            if (currentTypePack == tailCycleCheck)
-                throw InternalCompilerError("TypePackIterator detected a type pack cycle");
-        }
-
         currentIndex = 0;
     }
 
@@ -208,26 +197,6 @@ TypePackIterator end(TypePackId tp)
     return TypePackIterator{};
 }
 
-TypePackId getTail(TypePackId tp)
-{
-    DenseHashSet<TypePackId> seen{nullptr};
-    while (tp)
-    {
-        tp = follow(tp);
-
-        if (seen.contains(tp))
-            break;
-        seen.insert(tp);
-
-        if (auto pack = get<TypePack>(tp); pack && pack->tail)
-            tp = *pack->tail;
-        else
-            break;
-    }
-
-    return follow(tp);
-}
-
 bool areEqual(SeenSet& seen, const TypePackVar& lhs, const TypePackVar& rhs)
 {
     TypePackId lhsId = const_cast<TypePackId>(&lhs);

Analysis/src/TypePath.cpp

@@ -307,9 +307,9 @@ struct TraversalState
                 prop = &it->second;
             }
         }
-        else if (auto c = get<ExternType>(*currentType))
+        else if (auto c = get<ClassType>(*currentType))
         {
-            prop = lookupExternTypeProp(c, property.name);
+            prop = lookupClassProp(c, property.name);
         }
         // For a metatable type, the table takes priority; check that before
         // falling through to the metatable entry below.
@@ -461,7 +461,7 @@ struct TraversalState
                     indexer = &(*mtMt->indexer);
             }
             // Note: we don't appear to walk the class hierarchy for indexers
-            else if (auto ct = get<ExternType>(current); ct && ct->indexer)
+            else if (auto ct = get<ClassType>(current); ct && ct->indexer)
                 indexer = &(*ct->indexer);
 
             if (indexer)

Analysis/src/TypeUtils.cpp

@@ -11,9 +11,10 @@
 #include <algorithm>
 
 LUAU_FASTFLAG(LuauSolverV2);
-LUAU_FASTFLAG(LuauNonReentrantGeneralization2)
+LUAU_FASTFLAG(LuauAutocompleteRefactorsForIncrementalAutocomplete);
+LUAU_FASTFLAG(LuauTrackInteriorFreeTypesOnScope);
+LUAU_FASTFLAG(LuauFreeTypesMustHaveBounds)
 LUAU_FASTFLAG(LuauDisableNewSolverAssertsInMixedMode)
-
 namespace Luau
 {
 
@@ -303,11 +304,7 @@ TypePack extendTypePack(
             // also have to create a new tail.
 
             TypePack newPack;
-            newPack.tail = arena.freshTypePack(ftp->scope, ftp->polarity);
+            newPack.tail = arena.freshTypePack(ftp->scope);
-
-            if (FFlag::LuauNonReentrantGeneralization2)
-                trackInteriorFreeTypePack(ftp->scope, *newPack.tail);
-
             if (FFlag::LuauSolverV2)
                 result.tail = newPack.tail;
             size_t overridesIndex = 0;
@@ -322,12 +319,13 @@ TypePack extendTypePack(
                 {
                     if (FFlag::LuauSolverV2)
                     {
-                        FreeType ft{ftp->scope, builtinTypes->neverType, builtinTypes->unknownType, ftp->polarity};
+                        FreeType ft{ftp->scope, builtinTypes->neverType, builtinTypes->unknownType};
                         t = arena.addType(ft);
+                        if (FFlag::LuauTrackInteriorFreeTypesOnScope)
                             trackInteriorFreeType(ftp->scope, t);
                     }
                     else
-                        t = arena.freshType(builtinTypes, ftp->scope);
+                        t = FFlag::LuauFreeTypesMustHaveBounds ? arena.freshType(builtinTypes, ftp->scope) : arena.freshType_DEPRECATED(ftp->scope);
                 }
 
                 newPack.head.push_back(t);
@@ -434,6 +432,7 @@ TypeId stripNil(NotNull<BuiltinTypes> builtinTypes, TypeArena& arena, TypeId ty)
 
 ErrorSuppression shouldSuppressErrors(NotNull<Normalizer> normalizer, TypeId ty)
 {
+    LUAU_ASSERT(FFlag::LuauSolverV2 || FFlag::LuauAutocompleteRefactorsForIncrementalAutocomplete);
     std::shared_ptr<const NormalizedType> normType = normalizer->normalize(ty);
 
     if (!normType)
@@ -551,8 +550,10 @@ std::vector<TypeId> findBlockedArgTypesIn(AstExprCall* expr, NotNull<DenseHashMa
 
 void trackInteriorFreeType(Scope* scope, TypeId ty)
 {
-    if (!FFlag::LuauDisableNewSolverAssertsInMixedMode)
+    if (FFlag::LuauDisableNewSolverAssertsInMixedMode)
-        LUAU_ASSERT(FFlag::LuauSolverV2);
+        LUAU_ASSERT(FFlag::LuauTrackInteriorFreeTypesOnScope);
+    else
+        LUAU_ASSERT(FFlag::LuauSolverV2 && FFlag::LuauTrackInteriorFreeTypesOnScope);
     for (; scope; scope = scope->parent.get())
     {
         if (scope->interiorFreeTypes)
@@ -567,24 +568,4 @@ void trackInteriorFreeType(Scope* scope, TypeId ty)
     LUAU_ASSERT(!"No scopes in parent chain had a present `interiorFreeTypes` member.");
 }
 
-void trackInteriorFreeTypePack(Scope* scope, TypePackId tp)
-{
-    LUAU_ASSERT(tp);
-    if (!FFlag::LuauNonReentrantGeneralization2)
-        return;
-
-    for (; scope; scope = scope->parent.get())
-    {
-        if (scope->interiorFreeTypePacks)
-        {
-            scope->interiorFreeTypePacks->push_back(tp);
-            return;
-        }
-    }
-    // There should at least be *one* generalization constraint per module
-    // where `interiorFreeTypes` is present, which would be the one made
-    // by ConstraintGenerator::visitModuleRoot.
-    LUAU_ASSERT(!"No scopes in parent chain had a present `interiorFreeTypePacks` member.");
-}
-
 } // namespace Luau

Analysis/src/Unifier.cpp

@@ -22,6 +22,7 @@ LUAU_FASTFLAGVARIABLE(LuauTransitiveSubtyping)
 LUAU_FASTFLAG(LuauSolverV2)
 LUAU_FASTFLAGVARIABLE(LuauFixIndexerSubtypingOrdering)
 LUAU_FASTFLAGVARIABLE(LuauUnifierRecursionOnRestart)
+LUAU_FASTFLAG(LuauFreeTypesMustHaveBounds)
 
 namespace Luau
 {
@@ -291,7 +292,7 @@ TypePackId Widen::clean(TypePackId)
 
 bool Widen::ignoreChildren(TypeId ty)
 {
-    if (get<ExternType>(ty))
+    if (get<ClassType>(ty))
         return true;
 
     return !log->is<UnionType>(ty);
@@ -692,13 +693,13 @@ void Unifier::tryUnify_(TypeId subTy, TypeId superTy, bool isFunctionCall, bool
     else if (log.getMutable<MetatableType>(subTy))
         tryUnifyWithMetatable(superTy, subTy, /*reversed*/ true);
 
-    else if (log.getMutable<ExternType>(superTy))
+    else if (log.getMutable<ClassType>(superTy))
-        tryUnifyWithExternType(subTy, superTy, /*reversed*/ false);
+        tryUnifyWithClass(subTy, superTy, /*reversed*/ false);
 
-    // Unification of Luau types with extern types is almost, but not quite symmetrical.
+    // Unification of nonclasses with classes is almost, but not quite symmetrical.
-    // The order in which we perform this test is significant in the case that both types are extern types.
+    // The order in which we perform this test is significant in the case that both types are classes.
-    else if (log.getMutable<ExternType>(subTy))
+    else if (log.getMutable<ClassType>(subTy))
-        tryUnifyWithExternType(subTy, superTy, /*reversed*/ true);
+        tryUnifyWithClass(subTy, superTy, /*reversed*/ true);
 
     else if (log.get<NegationType>(superTy) || log.get<NegationType>(subTy))
         tryUnifyNegations(subTy, superTy);
@@ -1106,15 +1107,15 @@ void Unifier::tryUnifyNormalizedTypes(
         if (!get<PrimitiveType>(superNorm.errors))
             return reportError(location, TypeMismatch{superTy, subTy, reason, error, mismatchContext()});
 
-    for (const auto& [subExternType, _] : subNorm.externTypes.externTypes)
+    for (const auto& [subClass, _] : subNorm.classes.classes)
     {
         bool found = false;
-        const ExternType* subCtv = get<ExternType>(subExternType);
+        const ClassType* subCtv = get<ClassType>(subClass);
         LUAU_ASSERT(subCtv);
 
-        for (const auto& [superExternType, superNegations] : superNorm.externTypes.externTypes)
+        for (const auto& [superClass, superNegations] : superNorm.classes.classes)
         {
-            const ExternType* superCtv = get<ExternType>(superExternType);
+            const ClassType* superCtv = get<ClassType>(superClass);
             LUAU_ASSERT(superCtv);
 
             if (isSubclass(subCtv, superCtv))
@@ -1123,7 +1124,7 @@ void Unifier::tryUnifyNormalizedTypes(
 
                 for (TypeId negation : superNegations)
                 {
-                    const ExternType* negationCtv = get<ExternType>(negation);
+                    const ClassType* negationCtv = get<ClassType>(negation);
                     LUAU_ASSERT(negationCtv);
 
                     if (isSubclass(subCtv, negationCtv))
@@ -1558,7 +1559,7 @@ void Unifier::tryUnify_(TypePackId subTp, TypePackId superTp, bool isFunctionCal
             if (FFlag::LuauSolverV2)
                 return freshType(NotNull{types}, builtinTypes, scope);
             else
-                return types->freshType(builtinTypes, scope, level);
+                return FFlag::LuauFreeTypesMustHaveBounds ? types->freshType(builtinTypes, scope, level) : types->freshType_DEPRECATED(scope, level);
         };
 
         const TypePackId emptyTp = types->addTypePack(TypePack{{}, std::nullopt});
@@ -2381,8 +2382,8 @@ void Unifier::tryUnifyWithMetatable(TypeId subTy, TypeId superTy, bool reversed)
     }
 }
 
-// Extern type unification is almost, but not quite symmetrical.  We use the 'reversed' boolean to indicate which scenario we are evaluating.
+// Class unification is almost, but not quite symmetrical.  We use the 'reversed' boolean to indicate which scenario we are evaluating.
-void Unifier::tryUnifyWithExternType(TypeId subTy, TypeId superTy, bool reversed)
+void Unifier::tryUnifyWithClass(TypeId subTy, TypeId superTy, bool reversed)
 {
     if (reversed)
         std::swap(superTy, subTy);
@@ -2395,20 +2396,20 @@ void Unifier::tryUnifyWithExternType(TypeId subTy, TypeId superTy, bool reversed
             reportError(location, TypeMismatch{subTy, superTy, mismatchContext()});
     };
 
-    const ExternType* superExternType = get<ExternType>(superTy);
+    const ClassType* superClass = get<ClassType>(superTy);
-    if (!superExternType)
+    if (!superClass)
-        ice("tryUnifyExternType invoked with non-class Type");
+        ice("tryUnifyClass invoked with non-class Type");
 
-    if (const ExternType* subExternType = get<ExternType>(subTy))
+    if (const ClassType* subClass = get<ClassType>(subTy))
     {
         switch (variance)
         {
         case Covariant:
-            if (!isSubclass(subExternType, superExternType))
+            if (!isSubclass(subClass, superClass))
                 return fail();
             return;
         case Invariant:
-            if (subExternType != superExternType)
+            if (subClass != superClass)
                 return fail();
             return;
         }
@@ -2433,7 +2434,7 @@ void Unifier::tryUnifyWithExternType(TypeId subTy, TypeId superTy, bool reversed
 
         for (const auto& [propName, prop] : subTable->props)
         {
-            const Property* classProp = lookupExternTypeProp(superExternType, propName);
+            const Property* classProp = lookupClassProp(superClass, propName);
             if (!classProp)
             {
                 ok = false;
@@ -2461,7 +2462,7 @@ void Unifier::tryUnifyWithExternType(TypeId subTy, TypeId superTy, bool reversed
         if (subTable->indexer)
         {
             ok = false;
-            std::string msg = "Extern type " + superExternType->name + " does not have an indexer";
+            std::string msg = "Class " + superClass->name + " does not have an indexer";
             reportError(location, GenericError{msg});
         }
 
@@ -2634,9 +2635,9 @@ static void tryUnifyWithAny(
             queue.push_back(mt->table);
             queue.push_back(mt->metatable);
         }
-        else if (state.log.getMutable<ExternType>(ty))
+        else if (state.log.getMutable<ClassType>(ty))
         {
-            // ExternTypes never contain free types.
+            // ClassTypes never contain free types.
         }
         else if (auto union_ = state.log.getMutable<UnionType>(ty))
             queue.insert(queue.end(), union_->options.begin(), union_->options.end());
@@ -2653,7 +2654,7 @@ void Unifier::tryUnifyWithAny(TypeId subTy, TypeId anyTy)
     LUAU_ASSERT(get<AnyType>(anyTy) || get<ErrorType>(anyTy) || get<UnknownType>(anyTy) || get<NeverType>(anyTy));
 
     // These types are not visited in general loop below
-    if (log.get<PrimitiveType>(subTy) || log.get<AnyType>(subTy) || log.get<ExternType>(subTy))
+    if (log.get<PrimitiveType>(subTy) || log.get<AnyType>(subTy) || log.get<ClassType>(subTy))
         return;
 
     TypePackId anyTp = types->addTypePack(TypePackVar{VariadicTypePack{anyTy}});

Analysis/src/Unifier2.cpp

@@ -18,7 +18,8 @@
 #include <optional>
 
 LUAU_FASTINT(LuauTypeInferRecursionLimit)
-LUAU_FASTFLAG(LuauNonReentrantGeneralization2)
+LUAU_FASTFLAGVARIABLE(LuauUnifyMetatableWithAny)
+LUAU_FASTFLAG(LuauExtraFollows)
 
 namespace Luau
 {
@@ -236,9 +237,9 @@ bool Unifier2::unify(TypeId subTy, TypeId superTy)
     auto superMetatable = get<MetatableType>(superTy);
     if (subMetatable && superMetatable)
         return unify(subMetatable, superMetatable);
-    else if (subMetatable && superAny)
+    else if (FFlag::LuauUnifyMetatableWithAny && subMetatable && superAny)
         return unify(subMetatable, superAny);
-    else if (subAny && superMetatable)
+    else if (FFlag::LuauUnifyMetatableWithAny && subAny && superMetatable)
         return unify(subAny, superMetatable);
     else if (subMetatable) // if we only have one metatable, unify with the inner table
         return unify(subMetatable->table, superTy);
@@ -282,7 +283,7 @@ bool Unifier2::unifyFreeWithType(TypeId subTy, TypeId superTy)
     if (superArgTail)
         return doDefault();
 
-    const IntersectionType* upperBoundIntersection = get<IntersectionType>(upperBound);
+    const IntersectionType* upperBoundIntersection = get<IntersectionType>(FFlag::LuauExtraFollows ? upperBound : subFree->upperBound);
     if (!upperBoundIntersection)
         return doDefault();
 
@@ -319,25 +320,12 @@ bool Unifier2::unify(TypeId subTy, const FunctionType* superFn)
 
     if (shouldInstantiate)
     {
-        for (TypeId generic : subFn->generics)
+        for (auto generic : subFn->generics)
-        {
+            genericSubstitutions[generic] = freshType(arena, builtinTypes, scope);
-            const GenericType* gen = get<GenericType>(follow(generic));
-            if (gen)
-                genericSubstitutions[generic] = freshType(scope, gen->polarity);
-        }
 
-        for (TypePackId genericPack : subFn->genericPacks)
+        for (auto genericPack : subFn->genericPacks)
-        {
-            if (FFlag::LuauNonReentrantGeneralization2)
-            {
-                const GenericTypePack* gen = get<GenericTypePack>(follow(genericPack));
-                if (gen)
-                    genericPackSubstitutions[genericPack] = freshTypePack(scope, gen->polarity);
-            }
-            else
             genericPackSubstitutions[genericPack] = arena->freshTypePack(scope);
     }
-    }
 
     bool argResult = unify(superFn->argTypes, subFn->argTypes);
     bool retResult = unify(subFn->retTypes, superFn->retTypes);
@@ -445,6 +433,9 @@ bool Unifier2::unify(TableType* subTable, const TableType* superTable)
         superTypePackParamsIter++;
     }
 
+    if (subTable->selfTy && superTable->selfTy)
+        result &= unify(*subTable->selfTy, *superTable->selfTy);
+
     if (subTable->indexer && superTable->indexer)
     {
         result &= unify(subTable->indexer->indexType, superTable->indexer->indexType);
@@ -649,6 +640,208 @@ bool Unifier2::unify(TypePackId subTp, TypePackId superTp)
     return true;
 }
 
+struct FreeTypeSearcher : TypeVisitor
+{
+    NotNull<Scope> scope;
+
+    explicit FreeTypeSearcher(NotNull<Scope> scope)
+        : TypeVisitor(/*skipBoundTypes*/ true)
+        , scope(scope)
+    {
+    }
+
+    enum Polarity
+    {
+        Positive,
+        Negative,
+        Both,
+    };
+
+    Polarity polarity = Positive;
+
+    void flip()
+    {
+        switch (polarity)
+        {
+        case Positive:
+            polarity = Negative;
+            break;
+        case Negative:
+            polarity = Positive;
+            break;
+        case Both:
+            break;
+        }
+    }
+
+    DenseHashSet<const void*> seenPositive{nullptr};
+    DenseHashSet<const void*> seenNegative{nullptr};
+
+    bool seenWithCurrentPolarity(const void* ty)
+    {
+        switch (polarity)
+        {
+        case Positive:
+        {
+            if (seenPositive.contains(ty))
+                return true;
+
+            seenPositive.insert(ty);
+            return false;
+        }
+        case Negative:
+        {
+            if (seenNegative.contains(ty))
+                return true;
+
+            seenNegative.insert(ty);
+            return false;
+        }
+        case Both:
+        {
+            if (seenPositive.contains(ty) && seenNegative.contains(ty))
+                return true;
+
+            seenPositive.insert(ty);
+            seenNegative.insert(ty);
+            return false;
+        }
+        }
+
+        return false;
+    }
+
+    // The keys in these maps are either TypeIds or TypePackIds. It's safe to
+    // mix them because we only use these pointers as unique keys.  We never
+    // indirect them.
+    DenseHashMap<const void*, size_t> negativeTypes{0};
+    DenseHashMap<const void*, size_t> positiveTypes{0};
+
+    bool visit(TypeId ty) override
+    {
+        if (seenWithCurrentPolarity(ty))
+            return false;
+
+        LUAU_ASSERT(ty);
+        return true;
+    }
+
+    bool visit(TypeId ty, const FreeType& ft) override
+    {
+        if (seenWithCurrentPolarity(ty))
+            return false;
+
+        if (!subsumes(scope, ft.scope))
+            return true;
+
+        switch (polarity)
+        {
+        case Positive:
+            positiveTypes[ty]++;
+            break;
+        case Negative:
+            negativeTypes[ty]++;
+            break;
+        case Both:
+            positiveTypes[ty]++;
+            negativeTypes[ty]++;
+            break;
+        }
+
+        return true;
+    }
+
+    bool visit(TypeId ty, const TableType& tt) override
+    {
+        if (seenWithCurrentPolarity(ty))
+            return false;
+
+        if ((tt.state == TableState::Free || tt.state == TableState::Unsealed) && subsumes(scope, tt.scope))
+        {
+            switch (polarity)
+            {
+            case Positive:
+                positiveTypes[ty]++;
+                break;
+            case Negative:
+                negativeTypes[ty]++;
+                break;
+            case Both:
+                positiveTypes[ty]++;
+                negativeTypes[ty]++;
+                break;
+            }
+        }
+
+        for (const auto& [_name, prop] : tt.props)
+        {
+            if (prop.isReadOnly())
+                traverse(*prop.readTy);
+            else
+            {
+                LUAU_ASSERT(prop.isShared());
+
+                Polarity p = polarity;
+                polarity = Both;
+                traverse(prop.type());
+                polarity = p;
+            }
+        }
+
+        if (tt.indexer)
+        {
+            traverse(tt.indexer->indexType);
+            traverse(tt.indexer->indexResultType);
+        }
+
+        return false;
+    }
+
+    bool visit(TypeId ty, const FunctionType& ft) override
+    {
+        if (seenWithCurrentPolarity(ty))
+            return false;
+
+        flip();
+        traverse(ft.argTypes);
+        flip();
+
+        traverse(ft.retTypes);
+
+        return false;
+    }
+
+    bool visit(TypeId, const ClassType&) override
+    {
+        return false;
+    }
+
+    bool visit(TypePackId tp, const FreeTypePack& ftp) override
+    {
+        if (seenWithCurrentPolarity(tp))
+            return false;
+
+        if (!subsumes(scope, ftp.scope))
+            return true;
+
+        switch (polarity)
+        {
+        case Positive:
+            positiveTypes[tp]++;
+            break;
+        case Negative:
+            negativeTypes[tp]++;
+            break;
+        case Both:
+            positiveTypes[tp]++;
+            negativeTypes[tp]++;
+            break;
+        }
+
+        return true;
+    }
+};
+
 TypeId Unifier2::mkUnion(TypeId left, TypeId right)
 {
     left = follow(left);
@@ -748,23 +941,4 @@ OccursCheckResult Unifier2::occursCheck(DenseHashSet<TypePackId>& seen, TypePack
     return OccursCheckResult::Pass;
 }
 
-TypeId Unifier2::freshType(NotNull<Scope> scope, Polarity polarity)
-{
-    TypeId result = ::Luau::freshType(arena, builtinTypes, scope.get(), polarity);
-    newFreshTypes.emplace_back(result);
-    return result;
-}
-
-TypePackId Unifier2::freshTypePack(NotNull<Scope> scope, Polarity polarity)
-{
-    TypePackId result = arena->freshTypePack(scope.get());
-
-    auto ftp = getMutable<FreeTypePack>(result);
-    LUAU_ASSERT(ftp);
-    ftp->polarity = polarity;
-
-    newFreshTypePacks.emplace_back(result);
-    return result;
-}
-
 } // namespace Luau

Ast/include/Luau/Ast.h

@@ -87,8 +87,8 @@ struct AstLocal
 template<typename T>
 struct AstArray
 {
-    T* data = nullptr;
+    T* data;
-    size_t size = 0;
+    size_t size;
 
     const T* begin() const
     {
@@ -194,7 +194,6 @@ public:
     {
         Checked,
         Native,
-        Deprecated,
     };
 
     AstAttr(const Location& location, Type type);
@@ -446,25 +445,7 @@ public:
         AstStatBlock* body,
         size_t functionDepth,
         const AstName& debugname,
-        AstTypePack* returnAnnotation,
+        const std::optional<AstTypeList>& returnAnnotation = {},
-        AstTypePack* varargAnnotation = nullptr,
-        const std::optional<Location>& argLocation = std::nullopt
-    );
-
-    // Clip with FFlagLuauStoreReturnTypesAsPackOnAst
-    AstExprFunction(
-        const Location& location,
-        const AstArray<AstAttr*>& attributes,
-        const AstArray<AstGenericType*>& generics,
-        const AstArray<AstGenericTypePack*>& genericPacks,
-        AstLocal* self,
-        const AstArray<AstLocal*>& args,
-        bool vararg,
-        const Location& varargLocation,
-        AstStatBlock* body,
-        size_t functionDepth,
-        const AstName& debugname,
-        const std::optional<AstTypeList>& returnAnnotation,
         AstTypePack* varargAnnotation = nullptr,
         const std::optional<Location>& argLocation = std::nullopt
     );
@@ -472,16 +453,13 @@ public:
     void visit(AstVisitor* visitor) override;
 
     bool hasNativeAttribute() const;
-    bool hasAttribute(AstAttr::Type attributeType) const;
 
     AstArray<AstAttr*> attributes;
     AstArray<AstGenericType*> generics;
     AstArray<AstGenericTypePack*> genericPacks;
     AstLocal* self;
     AstArray<AstLocal*> args;
-    // Clip with FFlagLuauStoreReturnTypesAsPackOnAst
+    std::optional<AstTypeList> returnAnnotation;
-    std::optional<AstTypeList> returnAnnotation_DEPRECATED;
-    AstTypePack* returnAnnotation = nullptr;
     bool vararg = false;
     Location varargLocation;
     AstTypePack* varargAnnotation;
@@ -912,22 +890,14 @@ class AstStatTypeFunction : public AstStat
 public:
     LUAU_RTTI(AstStatTypeFunction);
 
-    AstStatTypeFunction(
+    AstStatTypeFunction(const Location& location, const AstName& name, const Location& nameLocation, AstExprFunction* body, bool exported);
-        const Location& location,
-        const AstName& name,
-        const Location& nameLocation,
-        AstExprFunction* body,
-        bool exported,
-        bool hasErrors
-    );
 
     void visit(AstVisitor* visitor) override;
 
     AstName name;
     Location nameLocation;
-    AstExprFunction* body = nullptr;
+    AstExprFunction* body;
-    bool exported = false;
+    bool exported;
-    bool hasErrors = false;
 };
 
 class AstStatDeclareGlobal : public AstStat
@@ -949,36 +919,6 @@ class AstStatDeclareFunction : public AstStat
 public:
     LUAU_RTTI(AstStatDeclareFunction)
 
-    // Clip with FFlagLuauStoreReturnTypesAsPackOnAst
-    AstStatDeclareFunction(
-        const Location& location,
-        const AstName& name,
-        const Location& nameLocation,
-        const AstArray<AstGenericType*>& generics,
-        const AstArray<AstGenericTypePack*>& genericPacks,
-        const AstTypeList& params,
-        const AstArray<AstArgumentName>& paramNames,
-        bool vararg,
-        const Location& varargLocation,
-        AstTypePack* retTypes
-    );
-
-    // Clip with FFlagLuauStoreReturnTypesAsPackOnAst
-    AstStatDeclareFunction(
-        const Location& location,
-        const AstArray<AstAttr*>& attributes,
-        const AstName& name,
-        const Location& nameLocation,
-        const AstArray<AstGenericType*>& generics,
-        const AstArray<AstGenericTypePack*>& genericPacks,
-        const AstTypeList& params,
-        const AstArray<AstArgumentName>& paramNames,
-        bool vararg,
-        const Location& varargLocation,
-        AstTypePack* retTypes
-    );
-
-    // Clip with FFlagLuauStoreReturnTypesAsPackOnAst
     AstStatDeclareFunction(
         const Location& location,
         const AstName& name,
@@ -992,7 +932,6 @@ public:
         const AstTypeList& retTypes
     );
 
-    // Clip with FFlagLuauStoreReturnTypesAsPackOnAst
     AstStatDeclareFunction(
         const Location& location,
         const AstArray<AstAttr*>& attributes,
@@ -1011,7 +950,6 @@ public:
     void visit(AstVisitor* visitor) override;
 
     bool isCheckedFunction() const;
-    bool hasAttribute(AstAttr::Type attributeType) const;
 
     AstArray<AstAttr*> attributes;
     AstName name;
@@ -1022,12 +960,10 @@ public:
     AstArray<AstArgumentName> paramNames;
     bool vararg = false;
     Location varargLocation;
-    AstTypePack* retTypes;
+    AstTypeList retTypes;
-    // Clip with FFlagLuauStoreReturnTypesAsPackOnAst
-    AstTypeList retTypes_DEPRECATED;
 };
 
-struct AstDeclaredExternTypeProperty
+struct AstDeclaredClassProp
 {
     AstName name;
     Location nameLocation;
@@ -1053,16 +989,16 @@ struct AstTableIndexer
     std::optional<Location> accessLocation;
 };
 
-class AstStatDeclareExternType : public AstStat
+class AstStatDeclareClass : public AstStat
 {
 public:
-    LUAU_RTTI(AstStatDeclareExternType)
+    LUAU_RTTI(AstStatDeclareClass)
 
-    AstStatDeclareExternType(
+    AstStatDeclareClass(
         const Location& location,
         const AstName& name,
         std::optional<AstName> superName,
-        const AstArray<AstDeclaredExternTypeProperty>& props,
+        const AstArray<AstDeclaredClassProp>& props,
         AstTableIndexer* indexer = nullptr
     );
 
@@ -1071,7 +1007,7 @@ public:
     AstName name;
     std::optional<AstName> superName;
 
-    AstArray<AstDeclaredExternTypeProperty> props;
+    AstArray<AstDeclaredClassProp> props;
     AstTableIndexer* indexer;
 };
 
@@ -1148,26 +1084,6 @@ class AstTypeFunction : public AstType
 public:
     LUAU_RTTI(AstTypeFunction)
 
-    AstTypeFunction(
-        const Location& location,
-        const AstArray<AstGenericType*>& generics,
-        const AstArray<AstGenericTypePack*>& genericPacks,
-        const AstTypeList& argTypes,
-        const AstArray<std::optional<AstArgumentName>>& argNames,
-        AstTypePack* returnTypes
-    );
-
-    AstTypeFunction(
-        const Location& location,
-        const AstArray<AstAttr*>& attributes,
-        const AstArray<AstGenericType*>& generics,
-        const AstArray<AstGenericTypePack*>& genericPacks,
-        const AstTypeList& argTypes,
-        const AstArray<std::optional<AstArgumentName>>& argNames,
-        AstTypePack* returnTypes
-    );
-
-    // Clip with FFlagLuauStoreReturnTypesAsPackOnAst
     AstTypeFunction(
         const Location& location,
         const AstArray<AstGenericType*>& generics,
@@ -1177,7 +1093,6 @@ public:
         const AstTypeList& returnTypes
     );
 
-    // Clip with FFlagLuauStoreReturnTypesAsPackOnAst
     AstTypeFunction(
         const Location& location,
         const AstArray<AstAttr*>& attributes,
@@ -1191,16 +1106,13 @@ public:
     void visit(AstVisitor* visitor) override;
 
     bool isCheckedFunction() const;
-    bool hasAttribute(AstAttr::Type attributeType) const;
 
     AstArray<AstAttr*> attributes;
     AstArray<AstGenericType*> generics;
     AstArray<AstGenericTypePack*> genericPacks;
     AstTypeList argTypes;
     AstArray<std::optional<AstArgumentName>> argNames;
-    // Clip with FFlagLuauStoreReturnTypesAsPackOnAst
+    AstTypeList returnTypes;
-    AstTypeList returnTypes_DEPRECATED;
-    AstTypePack* returnTypes;
 };
 
 class AstTypeTypeof : public AstType
@@ -1547,10 +1459,6 @@ public:
     {
         return visit(static_cast<AstStat*>(node));
     }
-    virtual bool visit(class AstStatTypeFunction* node)
-    {
-        return visit(static_cast<AstStat*>(node));
-    }
     virtual bool visit(class AstStatDeclareFunction* node)
     {
         return visit(static_cast<AstStat*>(node));
@@ -1559,7 +1467,7 @@ public:
     {
         return visit(static_cast<AstStat*>(node));
     }
-    virtual bool visit(class AstStatDeclareExternType* node)
+    virtual bool visit(class AstStatDeclareClass* node)
     {
         return visit(static_cast<AstStat*>(node));
     }

Ast/include/Luau/Cst.h

@@ -112,12 +112,11 @@ public:
 
     CstExprFunction();
 
-    Position functionKeywordPosition{0, 0};
+    Position openGenericsPosition{0,0};
-    Position openGenericsPosition{0, 0};
     AstArray<Position> genericsCommaPositions;
-    Position closeGenericsPosition{0, 0};
+    Position closeGenericsPosition{0,0};
     AstArray<Position> argsCommaPositions;
-    Position returnSpecifierPosition{0, 0};
+    Position returnSpecifierPosition{0,0};
 };
 
 class CstExprTable : public CstNode
@@ -275,24 +274,13 @@ public:
     Position opPosition;
 };
 
-class CstStatFunction : public CstNode
-{
-public:
-    LUAU_CST_RTTI(CstStatFunction)
-
-    explicit CstStatFunction(Position functionKeywordPosition);
-
-    Position functionKeywordPosition;
-};
-
 class CstStatLocalFunction : public CstNode
 {
 public:
     LUAU_CST_RTTI(CstStatLocalFunction)
 
-    explicit CstStatLocalFunction(Position localKeywordPosition, Position functionKeywordPosition);
+    explicit CstStatLocalFunction(Position functionKeywordPosition);
 
-    Position localKeywordPosition;
     Position functionKeywordPosition;
 };
 
@@ -388,7 +376,6 @@ public:
         std::optional<Position> separatorPosition;
 
         CstExprConstantString* stringInfo = nullptr; // only if Kind == StringProperty
-        Position stringPosition{0, 0}; // only if Kind == StringProperty
     };
 
     CstTypeTable(AstArray<Item> items, bool isArray);
@@ -434,28 +421,6 @@ public:
     Position closePosition;
 };
 
-class CstTypeUnion : public CstNode
-{
-public:
-    LUAU_CST_RTTI(CstTypeUnion)
-
-    CstTypeUnion(std::optional<Position> leadingPosition, AstArray<Position> separatorPositions);
-
-    std::optional<Position> leadingPosition;
-    AstArray<Position> separatorPositions;
-};
-
-class CstTypeIntersection : public CstNode
-{
-public:
-    LUAU_CST_RTTI(CstTypeIntersection)
-
-    explicit CstTypeIntersection(std::optional<Position> leadingPosition, AstArray<Position> separatorPositions);
-
-    std::optional<Position> leadingPosition;
-    AstArray<Position> separatorPositions;
-};
-
 class CstTypeSingletonString : public CstNode
 {
 public:
@@ -473,10 +438,8 @@ class CstTypePackExplicit : public CstNode
 public:
     LUAU_CST_RTTI(CstTypePackExplicit)
 
-    explicit CstTypePackExplicit();
+    CstTypePackExplicit(Position openParenthesesPosition, Position closeParenthesesPosition, AstArray<Position> commaPositions);
-    explicit CstTypePackExplicit(Position openParenthesesPosition, Position closeParenthesesPosition, AstArray<Position> commaPositions);
 
-    bool hasParentheses;
     Position openParenthesesPosition;
     Position closeParenthesesPosition;
     AstArray<Position> commaPositions;

Ast/include/Luau/Parser.h

@@ -125,7 +125,7 @@ private:
     AstStat* parseFor();
 
     // funcname ::= Name {`.' Name} [`:' Name]
-    AstExpr* parseFunctionName(bool& hasself, AstName& debugname);
+    AstExpr* parseFunctionName(Location start_DEPRECATED, bool& hasself, AstName& debugname);
 
     // function funcname funcbody
     LUAU_FORCEINLINE AstStat* parseFunctionStat(const AstArray<AstAttr*>& attributes = {nullptr, 0});
@@ -157,9 +157,7 @@ private:
     // type function Name ... end
     AstStat* parseTypeFunction(const Location& start, bool exported, Position typeKeywordPosition);
 
-    AstDeclaredExternTypeProperty parseDeclaredExternTypeMethod(const AstArray<AstAttr*>& attributes);
+    AstDeclaredClassProp parseDeclaredClassMethod();
-    AstDeclaredExternTypeProperty parseDeclaredExternTypeMethod_DEPRECATED();
-
 
     // `declare global' Name: Type |
     // `declare function' Name`(' [parlist] `)' [`:` Type]
@@ -182,14 +180,6 @@ private:
         const Name* localName,
         const AstArray<AstAttr*>& attributes
     );
-    // Clip with FFlagLuauStoreReturnTypesAsPackOnAst
-    std::pair<AstExprFunction*, AstLocal*> parseFunctionBody_DEPRECATED(
-        bool hasself,
-        const Lexeme& matchFunction,
-        const AstName& debugname,
-        const Name* localName,
-        const AstArray<AstAttr*>& attributes
-    );
 
     // explist ::= {exp `,'} exp
     void parseExprList(TempVector<AstExpr*>& result, TempVector<Position>* commaPositions = nullptr);
@@ -227,12 +217,8 @@ private:
         TempVector<std::optional<Position>>* nameColonPositions = nullptr
     );
 
-    AstTypePack* parseOptionalReturnType(Position* returnSpecifierPosition = nullptr);
+    std::optional<AstTypeList> parseOptionalReturnType(Position* returnSpecifierPosition = nullptr);
-    AstTypePack* parseReturnType();
+    std::pair<Location, AstTypeList> parseReturnType();
-
-    // Clip with FFlagLuauStoreReturnTypesAsPackOnAst
-    std::optional<AstTypeList> parseOptionalReturnType_DEPRECATED(Position* returnSpecifierPosition = nullptr);
-    std::pair<Location, AstTypeList> parseReturnType_DEPRECATED();
 
     struct TableIndexerResult
     {
@@ -242,9 +228,9 @@ private:
         Position colonPosition;
     };
 
-    TableIndexerResult parseTableIndexer(AstTableAccess access, std::optional<Location> accessLocation, Lexeme begin);
+    TableIndexerResult parseTableIndexer(AstTableAccess access, std::optional<Location> accessLocation);
-    // Remove with FFlagLuauStoreCSTData2
+    // Remove with FFlagLuauStoreCSTData
-    AstTableIndexer* parseTableIndexer_DEPRECATED(AstTableAccess access, std::optional<Location> accessLocation, Lexeme begin);
+    AstTableIndexer* parseTableIndexer_DEPRECATED(AstTableAccess access, std::optional<Location> accessLocation);
 
     AstTypeOrPack parseFunctionType(bool allowPack, const AstArray<AstAttr*>& attributes);
     AstType* parseFunctionTypeTail(
@@ -503,7 +489,7 @@ private:
     std::vector<CstTypeTable::Item> scratchCstTableTypeProps;
     std::vector<AstType*> scratchType;
     std::vector<AstTypeOrPack> scratchTypeOrPack;
-    std::vector<AstDeclaredExternTypeProperty> scratchDeclaredClassProps;
+    std::vector<AstDeclaredClassProp> scratchDeclaredClassProps;
     std::vector<AstExprTable::Item> scratchItem;
     std::vector<CstExprTable::Item> scratchCstItem;
     std::vector<AstArgumentName> scratchArgName;

Ast/src/Ast.cpp

@@ -3,25 +3,9 @@
 
 #include "Luau/Common.h"
 
-LUAU_FASTFLAG(LuauDeprecatedAttribute);
-LUAU_FASTFLAG(LuauStoreReturnTypesAsPackOnAst)
-
 namespace Luau
 {
 
-static bool hasAttributeInArray(const AstArray<AstAttr*> attributes, AstAttr::Type attributeType)
-{
-    LUAU_ASSERT(FFlag::LuauDeprecatedAttribute);
-
-    for (const auto attribute : attributes)
-    {
-        if (attribute->type == attributeType)
-            return true;
-    }
-
-    return false;
-}
-
 static void visitTypeList(AstVisitor* visitor, const AstTypeList& list)
 {
     for (AstType* ty : list.types)
@@ -242,7 +226,7 @@ AstExprFunction::AstExprFunction(
     AstStatBlock* body,
     size_t functionDepth,
     const AstName& debugname,
-    AstTypePack* returnAnnotation,
+    const std::optional<AstTypeList>& returnAnnotation,
     AstTypePack* varargAnnotation,
     const std::optional<Location>& argLocation
 )
@@ -261,41 +245,6 @@ AstExprFunction::AstExprFunction(
     , debugname(debugname)
     , argLocation(argLocation)
 {
-    LUAU_ASSERT(FFlag::LuauStoreReturnTypesAsPackOnAst);
-}
-
-AstExprFunction::AstExprFunction(
-    const Location& location,
-    const AstArray<AstAttr*>& attributes,
-    const AstArray<AstGenericType*>& generics,
-    const AstArray<AstGenericTypePack*>& genericPacks,
-    AstLocal* self,
-    const AstArray<AstLocal*>& args,
-    bool vararg,
-    const Location& varargLocation,
-    AstStatBlock* body,
-    size_t functionDepth,
-    const AstName& debugname,
-    const std::optional<AstTypeList>& returnAnnotation,
-    AstTypePack* varargAnnotation,
-    const std::optional<Location>& argLocation
-)
-    : AstExpr(ClassIndex(), location)
-    , attributes(attributes)
-    , generics(generics)
-    , genericPacks(genericPacks)
-    , self(self)
-    , args(args)
-    , returnAnnotation_DEPRECATED(returnAnnotation)
-    , vararg(vararg)
-    , varargLocation(varargLocation)
-    , varargAnnotation(varargAnnotation)
-    , body(body)
-    , functionDepth(functionDepth)
-    , debugname(debugname)
-    , argLocation(argLocation)
-{
-    LUAU_ASSERT(!FFlag::LuauStoreReturnTypesAsPackOnAst);
 }
 
 void AstExprFunction::visit(AstVisitor* visitor)
@@ -311,16 +260,8 @@ void AstExprFunction::visit(AstVisitor* visitor)
         if (varargAnnotation)
             varargAnnotation->visit(visitor);
 
-        if (FFlag::LuauStoreReturnTypesAsPackOnAst)
-        {
         if (returnAnnotation)
-                returnAnnotation->visit(visitor);
+            visitTypeList(visitor, *returnAnnotation);
-        }
-        else
-        {
-            if (returnAnnotation_DEPRECATED)
-                visitTypeList(visitor, *returnAnnotation_DEPRECATED);
-        }
 
         body->visit(visitor);
     }
@@ -336,13 +277,6 @@ bool AstExprFunction::hasNativeAttribute() const
     return false;
 }
 
-bool AstExprFunction::hasAttribute(const AstAttr::Type attributeType) const
-{
-    LUAU_ASSERT(FFlag::LuauDeprecatedAttribute);
-
-    return hasAttributeInArray(attributes, attributeType);
-}
-
 AstExprTable::AstExprTable(const Location& location, const AstArray<Item>& items)
     : AstExpr(ClassIndex(), location)
     , items(items)
@@ -857,15 +791,13 @@ AstStatTypeFunction::AstStatTypeFunction(
     const AstName& name,
     const Location& nameLocation,
     AstExprFunction* body,
-    bool exported,
+    bool exported
-    bool hasErrors
 )
     : AstStat(ClassIndex(), location)
     , name(name)
     , nameLocation(nameLocation)
     , body(body)
     , exported(exported)
-    , hasErrors(hasErrors)
 {
 }
 
@@ -889,62 +821,6 @@ void AstStatDeclareGlobal::visit(AstVisitor* visitor)
         type->visit(visitor);
 }
 
-AstStatDeclareFunction::AstStatDeclareFunction(
-    const Location& location,
-    const AstName& name,
-    const Location& nameLocation,
-    const AstArray<AstGenericType*>& generics,
-    const AstArray<AstGenericTypePack*>& genericPacks,
-    const AstTypeList& params,
-    const AstArray<AstArgumentName>& paramNames,
-    bool vararg,
-    const Location& varargLocation,
-    AstTypePack* retTypes
-)
-    : AstStat(ClassIndex(), location)
-    , attributes()
-    , name(name)
-    , nameLocation(nameLocation)
-    , generics(generics)
-    , genericPacks(genericPacks)
-    , params(params)
-    , paramNames(paramNames)
-    , vararg(vararg)
-    , varargLocation(varargLocation)
-    , retTypes(retTypes)
-{
-    LUAU_ASSERT(FFlag::LuauStoreReturnTypesAsPackOnAst);
-}
-
-AstStatDeclareFunction::AstStatDeclareFunction(
-    const Location& location,
-    const AstArray<AstAttr*>& attributes,
-    const AstName& name,
-    const Location& nameLocation,
-    const AstArray<AstGenericType*>& generics,
-    const AstArray<AstGenericTypePack*>& genericPacks,
-    const AstTypeList& params,
-    const AstArray<AstArgumentName>& paramNames,
-    bool vararg,
-    const Location& varargLocation,
-    AstTypePack* retTypes
-)
-    : AstStat(ClassIndex(), location)
-    , attributes(attributes)
-    , name(name)
-    , nameLocation(nameLocation)
-    , generics(generics)
-    , genericPacks(genericPacks)
-    , params(params)
-    , paramNames(paramNames)
-    , vararg(vararg)
-    , varargLocation(varargLocation)
-    , retTypes(retTypes)
-{
-    LUAU_ASSERT(FFlag::LuauStoreReturnTypesAsPackOnAst);
-}
-
-// Clip with FFlagLuauStoreReturnTypesAsPackOnAst
 AstStatDeclareFunction::AstStatDeclareFunction(
     const Location& location,
     const AstName& name,
@@ -967,12 +843,10 @@ AstStatDeclareFunction::AstStatDeclareFunction(
     , paramNames(paramNames)
     , vararg(vararg)
     , varargLocation(varargLocation)
-    , retTypes_DEPRECATED(retTypes)
+    , retTypes(retTypes)
 {
-    LUAU_ASSERT(!FFlag::LuauStoreReturnTypesAsPackOnAst);
 }
 
-// Clip with FFlagLuauStoreReturnTypesAsPackOnAst
 AstStatDeclareFunction::AstStatDeclareFunction(
     const Location& location,
     const AstArray<AstAttr*>& attributes,
@@ -996,9 +870,8 @@ AstStatDeclareFunction::AstStatDeclareFunction(
     , paramNames(paramNames)
     , vararg(vararg)
     , varargLocation(varargLocation)
-    , retTypes_DEPRECATED(retTypes)
+    , retTypes(retTypes)
 {
-    LUAU_ASSERT(!FFlag::LuauStoreReturnTypesAsPackOnAst);
 }
 
 void AstStatDeclareFunction::visit(AstVisitor* visitor)
@@ -1006,10 +879,7 @@ void AstStatDeclareFunction::visit(AstVisitor* visitor)
     if (visitor->visit(this))
     {
         visitTypeList(visitor, params);
-        if (FFlag::LuauStoreReturnTypesAsPackOnAst)
+        visitTypeList(visitor, retTypes);
-            retTypes->visit(visitor);
-        else
-            visitTypeList(visitor, retTypes_DEPRECATED);
     }
 }
 
@@ -1024,18 +894,11 @@ bool AstStatDeclareFunction::isCheckedFunction() const
     return false;
 }
 
-bool AstStatDeclareFunction::hasAttribute(AstAttr::Type attributeType) const
+AstStatDeclareClass::AstStatDeclareClass(
-{
-    LUAU_ASSERT(FFlag::LuauDeprecatedAttribute);
-
-    return hasAttributeInArray(attributes, attributeType);
-}
-
-AstStatDeclareExternType::AstStatDeclareExternType(
     const Location& location,
     const AstName& name,
     std::optional<AstName> superName,
-    const AstArray<AstDeclaredExternTypeProperty>& props,
+    const AstArray<AstDeclaredClassProp>& props,
     AstTableIndexer* indexer
 )
     : AstStat(ClassIndex(), location)
@@ -1046,11 +909,11 @@ AstStatDeclareExternType::AstStatDeclareExternType(
 {
 }
 
-void AstStatDeclareExternType::visit(AstVisitor* visitor)
+void AstStatDeclareClass::visit(AstVisitor* visitor)
 {
     if (visitor->visit(this))
     {
-        for (const AstDeclaredExternTypeProperty& prop : props)
+        for (const AstDeclaredClassProp& prop : props)
             prop.ty->visit(visitor);
     }
 }
@@ -1135,48 +998,6 @@ void AstTypeTable::visit(AstVisitor* visitor)
     }
 }
 
-AstTypeFunction::AstTypeFunction(
-    const Location& location,
-    const AstArray<AstGenericType*>& generics,
-    const AstArray<AstGenericTypePack*>& genericPacks,
-    const AstTypeList& argTypes,
-    const AstArray<std::optional<AstArgumentName>>& argNames,
-    AstTypePack* returnTypes
-)
-    : AstType(ClassIndex(), location)
-    , attributes()
-    , generics(generics)
-    , genericPacks(genericPacks)
-    , argTypes(argTypes)
-    , argNames(argNames)
-    , returnTypes(returnTypes)
-{
-    LUAU_ASSERT(FFlag::LuauStoreReturnTypesAsPackOnAst);
-    LUAU_ASSERT(argNames.size == 0 || argNames.size == argTypes.types.size);
-}
-
-AstTypeFunction::AstTypeFunction(
-    const Location& location,
-    const AstArray<AstAttr*>& attributes,
-    const AstArray<AstGenericType*>& generics,
-    const AstArray<AstGenericTypePack*>& genericPacks,
-    const AstTypeList& argTypes,
-    const AstArray<std::optional<AstArgumentName>>& argNames,
-    AstTypePack* returnTypes
-)
-    : AstType(ClassIndex(), location)
-    , attributes(attributes)
-    , generics(generics)
-    , genericPacks(genericPacks)
-    , argTypes(argTypes)
-    , argNames(argNames)
-    , returnTypes(returnTypes)
-{
-    LUAU_ASSERT(FFlag::LuauStoreReturnTypesAsPackOnAst);
-    LUAU_ASSERT(argNames.size == 0 || argNames.size == argTypes.types.size);
-}
-
-// Clip with FFlagLuauStoreReturnTypesAsPackOnAst
 AstTypeFunction::AstTypeFunction(
     const Location& location,
     const AstArray<AstGenericType*>& generics,
@@ -1191,13 +1012,11 @@ AstTypeFunction::AstTypeFunction(
     , genericPacks(genericPacks)
     , argTypes(argTypes)
     , argNames(argNames)
-    , returnTypes_DEPRECATED(returnTypes)
+    , returnTypes(returnTypes)
 {
-    LUAU_ASSERT(!FFlag::LuauStoreReturnTypesAsPackOnAst);
     LUAU_ASSERT(argNames.size == 0 || argNames.size == argTypes.types.size);
 }
 
-// Clip with FFlagLuauStoreReturnTypesAsPackOnAst
 AstTypeFunction::AstTypeFunction(
     const Location& location,
     const AstArray<AstAttr*>& attributes,
@@ -1213,9 +1032,8 @@ AstTypeFunction::AstTypeFunction(
     , genericPacks(genericPacks)
     , argTypes(argTypes)
     , argNames(argNames)
-    , returnTypes_DEPRECATED(returnTypes)
+    , returnTypes(returnTypes)
 {
-    LUAU_ASSERT(!FFlag::LuauStoreReturnTypesAsPackOnAst);
     LUAU_ASSERT(argNames.size == 0 || argNames.size == argTypes.types.size);
 }
 
@@ -1224,10 +1042,7 @@ void AstTypeFunction::visit(AstVisitor* visitor)
     if (visitor->visit(this))
     {
         visitTypeList(visitor, argTypes);
-        if (FFlag::LuauStoreReturnTypesAsPackOnAst)
+        visitTypeList(visitor, returnTypes);
-            returnTypes->visit(visitor);
-        else
-            visitTypeList(visitor, returnTypes_DEPRECATED);
     }
 }
 
@@ -1242,13 +1057,6 @@ bool AstTypeFunction::isCheckedFunction() const
     return false;
 }
 
-bool AstTypeFunction::hasAttribute(AstAttr::Type attributeType) const
-{
-    LUAU_ASSERT(FFlag::LuauDeprecatedAttribute);
-
-    return hasAttributeInArray(attributes, attributeType);
-}
-
 AstTypeTypeof::AstTypeTypeof(const Location& location, AstExpr* expr)
     : AstType(ClassIndex(), location)
     , expr(expr)

Ast/src/Cst.cpp

@@ -38,8 +38,7 @@ CstExprIndexExpr::CstExprIndexExpr(Position openBracketPosition, Position closeB
 {
 }
 
-CstExprFunction::CstExprFunction()
+CstExprFunction::CstExprFunction() : CstNode(CstClassIndex())
-    : CstNode(CstClassIndex())
 {
 }
 
@@ -130,19 +129,12 @@ CstStatCompoundAssign::CstStatCompoundAssign(Position opPosition)
 {
 }
 
-CstStatFunction::CstStatFunction(Position functionKeywordPosition)
+CstStatLocalFunction::CstStatLocalFunction(Position functionKeywordPosition)
     : CstNode(CstClassIndex())
     , functionKeywordPosition(functionKeywordPosition)
 {
 }
 
-CstStatLocalFunction::CstStatLocalFunction(Position localKeywordPosition, Position functionKeywordPosition)
-    : CstNode(CstClassIndex())
-    , localKeywordPosition(localKeywordPosition)
-    , functionKeywordPosition(functionKeywordPosition)
-{
-}
-
 CstGenericType::CstGenericType(std::optional<Position> defaultEqualsPosition)
     : CstNode(CstClassIndex())
     , defaultEqualsPosition(defaultEqualsPosition)
@@ -229,20 +221,6 @@ CstTypeTypeof::CstTypeTypeof(Position openPosition, Position closePosition)
 {
 }
 
-CstTypeUnion::CstTypeUnion(std::optional<Position> leadingPosition, AstArray<Position> separatorPositions)
-    : CstNode(CstClassIndex())
-    , leadingPosition(leadingPosition)
-    , separatorPositions(separatorPositions)
-{
-}
-
-CstTypeIntersection::CstTypeIntersection(std::optional<Position> leadingPosition, AstArray<Position> separatorPositions)
-    : CstNode(CstClassIndex())
-    , leadingPosition(leadingPosition)
-    , separatorPositions(separatorPositions)
-{
-}
-
 CstTypeSingletonString::CstTypeSingletonString(AstArray<char> sourceString, CstExprConstantString::QuoteStyle quoteStyle, unsigned int blockDepth)
     : CstNode(CstClassIndex())
     , sourceString(sourceString)
@@ -252,18 +230,8 @@ CstTypeSingletonString::CstTypeSingletonString(AstArray<char> sourceString, CstE
     LUAU_ASSERT(quoteStyle != CstExprConstantString::QuotedInterp);
 }
 
-CstTypePackExplicit::CstTypePackExplicit()
-    : CstNode(CstClassIndex())
-    , hasParentheses(false)
-    , openParenthesesPosition(Position{0, 0})
-    , closeParenthesesPosition(Position{0, 0})
-    , commaPositions({})
-{
-}
-
 CstTypePackExplicit::CstTypePackExplicit(Position openParenthesesPosition, Position closeParenthesesPosition, AstArray<Position> commaPositions)
     : CstNode(CstClassIndex())
-    , hasParentheses(true)
     , openParenthesesPosition(openParenthesesPosition)
     , closeParenthesesPosition(closeParenthesesPosition)
     , commaPositions(commaPositions)