Sync to upstream/release/624 (#1245)

# What's changed?

* Optimize table.maxn.  This function is now 5-14x faster
* Reserve Luau stack space for error message.

## New Solver

* Globals can be type-stated, but only if they are already in scope
* Fix a stack overflow that could occur when normalizing certain kinds
of recursive unions of intersections (of unions of intersections...)
* Fix an assertion failure that would trigger when the __iter metamethod
has a bad signature

## Native Codegen

* Type propagation and temporary register type hints
* Direct vector property access should only happen for names of right
length
* BytecodeAnalysis will only predict that some of the vector value
fields are numbers

---

## Internal Contributors

Co-authored-by: Alexander McCord <amccord@roblox.com>
Co-authored-by: Andy Friesen <afriesen@roblox.com>
Co-authored-by: Aviral Goel <agoel@roblox.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>

Analysis/include/Luau/Normalize.h

@@ -395,6 +395,7 @@ public:
     TypeId negate(TypeId there);
     void subtractPrimitive(NormalizedType& here, TypeId ty);
     void subtractSingleton(NormalizedType& here, TypeId ty);
+    NormalizationResult intersectNormalWithNegationTy(TypeId toNegate, NormalizedType& intersect, bool useDeprecated = false);
 
     // ------- Normalizing intersections
     TypeId intersectionOfTops(TypeId here, TypeId there);

Analysis/src/ConstraintGenerator.cpp

@@ -1900,10 +1900,7 @@ Inference ConstraintGenerator::check(const ScopePtr& scope, AstExprGlobal* globa
         return Inference{*ty, refinementArena.proposition(key, builtinTypes->truthyType)};
     }
     else
-    {
-        reportError(global->location, UnknownSymbol{global->name.value, UnknownSymbol::Binding});
         return Inference{builtinTypes->errorRecoveryType()};
-    }
 }
 
 Inference ConstraintGenerator::checkIndexName(const ScopePtr& scope, const RefinementKey* key, AstExpr* indexee, const std::string& index, Location indexLocation)
@@ -2453,7 +2450,12 @@ ConstraintGenerator::LValueBounds ConstraintGenerator::checkLValue(const ScopePt
 {
     std::optional<TypeId> annotatedTy = scope->lookup(Symbol{global->name});
     if (annotatedTy)
-        return {annotatedTy, arena->addType(BlockedType{})};
+    {
+        DefId def = dfg->getDef(global);
+        TypeId assignedTy = arena->addType(BlockedType{});
+        rootScope->lvalueTypes[def] = assignedTy;
+        return {annotatedTy, assignedTy};
+    }
     else
         return {annotatedTy, std::nullopt};
 }

Analysis/src/ConstraintSolver.cpp

@@ -1619,9 +1619,7 @@ std::pair<bool, std::optional<TypeId>> ConstraintSolver::tryDispatchSetIndexer(
     {
         if (tt->indexer)
         {
-            if (isBlocked(tt->indexer->indexType))
+            if (isBlocked(tt->indexer->indexResultType))
-                return {block(tt->indexer->indexType, constraint), std::nullopt};
-            else if (isBlocked(tt->indexer->indexResultType))
                 return {block(tt->indexer->indexResultType, constraint), std::nullopt};
 
             unify(constraint, indexType, tt->indexer->indexType);
@@ -2014,10 +2012,14 @@ bool ConstraintSolver::tryDispatchIterableTable(TypeId iteratorTy, const Iterabl
                 if (std::optional<TypeId> instantiatedNextFn = instantiate(builtinTypes, arena, NotNull{&limits}, constraint->scope, nextFn))
                 {
                     const FunctionType* nextFn = get<FunctionType>(*instantiatedNextFn);
-                    LUAU_ASSERT(nextFn);
-                    const TypePackId nextRetPack = nextFn->retTypes;
 
-                    pushConstraint(constraint->scope, constraint->location, UnpackConstraint{c.variables, nextRetPack, /* resultIsLValue=*/true});
+                    // If nextFn is nullptr, then the iterator function has an improper signature.
+                    if (nextFn)
+                    {
+                        const TypePackId nextRetPack = nextFn->retTypes;
+                        pushConstraint(constraint->scope, constraint->location, UnpackConstraint{c.variables, nextRetPack, /* resultIsLValue=*/true});
+                    }
+
                     return true;
                 }
                 else

Analysis/src/Normalize.cpp

@@ -20,6 +20,7 @@ LUAU_FASTFLAGVARIABLE(LuauNormalizeAwayUninhabitableTables, false)
 LUAU_FASTFLAGVARIABLE(LuauFixNormalizeCaching, false);
 LUAU_FASTFLAGVARIABLE(LuauNormalizeNotUnknownIntersection, false);
 LUAU_FASTFLAGVARIABLE(LuauFixCyclicUnionsOfIntersections, false);
+LUAU_FASTFLAGVARIABLE(LuauFixReduceStackPressure, false);
 
 // This could theoretically be 2000 on amd64, but x86 requires this.
 LUAU_FASTINTVARIABLE(LuauNormalizeIterationLimit, 1200);
@@ -36,6 +37,11 @@ static bool fixCyclicUnionsOfIntersections()
     return FFlag::LuauFixCyclicUnionsOfIntersections || FFlag::DebugLuauDeferredConstraintResolution;
 }
 
+static bool fixReduceStackPressure()
+{
+    return FFlag::LuauFixReduceStackPressure || FFlag::DebugLuauDeferredConstraintResolution;
+}
+
 namespace Luau
 {
 
@@ -45,6 +51,14 @@ static bool normalizeAwayUninhabitableTables()
     return FFlag::LuauNormalizeAwayUninhabitableTables || FFlag::DebugLuauDeferredConstraintResolution;
 }
 
+static bool shouldEarlyExit(NormalizationResult res)
+{
+    // if res is hit limits, return control flow
+    if (res == NormalizationResult::HitLimits || res == NormalizationResult::False)
+        return true;
+    return false;
+}
+
 TypeIds::TypeIds(std::initializer_list<TypeId> tys)
 {
     for (TypeId ty : tys)
@@ -1729,6 +1743,27 @@ bool Normalizer::withinResourceLimits()
     return true;
 }
 
+NormalizationResult Normalizer::intersectNormalWithNegationTy(TypeId toNegate, NormalizedType& intersect, bool useDeprecated)
+{
+
+    std::optional<NormalizedType> negated;
+    if (useDeprecated)
+    {
+        const NormalizedType* normal = DEPRECATED_normalize(toNegate);
+        negated = negateNormal(*normal);
+    }
+    else
+    {
+        std::shared_ptr<const NormalizedType> normal = normalize(toNegate);
+        negated = negateNormal(*normal);
+    }
+
+    if (!negated)
+        return NormalizationResult::False;
+    intersectNormals(intersect, *negated);
+    return NormalizationResult::True;
+}
+
 // See above for an explaination of `ignoreSmallerTyvars`.
 NormalizationResult Normalizer::unionNormalWithTy(NormalizedType& here, TypeId there, Set<TypeId>& seenSetTypes, int ignoreSmallerTyvars)
 {
@@ -2541,8 +2576,8 @@ std::optional<TypeId> Normalizer::intersectionOfTables(TypeId here, TypeId there
         state = tttv->state;
 
     TypeLevel level = max(httv->level, tttv->level);
-    TableType result{state, level};
 
+    std::unique_ptr<TableType> result = nullptr;
     bool hereSubThere = true;
     bool thereSubHere = true;
 
@@ -2563,8 +2598,18 @@ std::optional<TypeId> Normalizer::intersectionOfTables(TypeId here, TypeId there
                     if (tprop.readTy.has_value())
                     {
                         // if the intersection of the read types of a property is uninhabited, the whole table is `never`.
-                        if (normalizeAwayUninhabitableTables() && NormalizationResult::False == isIntersectionInhabited(*hprop.readTy, *tprop.readTy))
+                        if (fixReduceStackPressure())
-                            return {builtinTypes->neverType};
+                        {
+                            if (normalizeAwayUninhabitableTables() &&
+                                NormalizationResult::True != isIntersectionInhabited(*hprop.readTy, *tprop.readTy))
+                                return {builtinTypes->neverType};
+                        }
+                        else
+                        {
+                            if (normalizeAwayUninhabitableTables() &&
+                                NormalizationResult::False == isIntersectionInhabited(*hprop.readTy, *tprop.readTy))
+                                return {builtinTypes->neverType};
+                        }
 
                         TypeId ty = simplifyIntersection(builtinTypes, NotNull{arena}, *hprop.readTy, *tprop.readTy).result;
                         prop.readTy = ty;
@@ -2614,14 +2659,21 @@ std::optional<TypeId> Normalizer::intersectionOfTables(TypeId here, TypeId there
         // TODO: string indexers
 
         if (prop.readTy || prop.writeTy)
-            result.props[name] = prop;
+        {
+            if (!result.get())
+                result = std::make_unique<TableType>(TableType{state, level});
+            result->props[name] = prop;
+        }
     }
 
     for (const auto& [name, tprop] : tttv->props)
     {
         if (httv->props.count(name) == 0)
         {
-            result.props[name] = tprop;
+            if (!result.get())
+                result = std::make_unique<TableType>(TableType{state, level});
+
+            result->props[name] = tprop;
             hereSubThere = false;
         }
     }
@@ -2631,18 +2683,24 @@ std::optional<TypeId> Normalizer::intersectionOfTables(TypeId here, TypeId there
         // TODO: What should intersection of indexes be?
         TypeId index = unionType(httv->indexer->indexType, tttv->indexer->indexType);
         TypeId indexResult = intersectionType(httv->indexer->indexResultType, tttv->indexer->indexResultType);
-        result.indexer = {index, indexResult};
+        if (!result.get())
+            result = std::make_unique<TableType>(TableType{state, level});
+        result->indexer = {index, indexResult};
         hereSubThere &= (httv->indexer->indexType == index) && (httv->indexer->indexResultType == indexResult);
         thereSubHere &= (tttv->indexer->indexType == index) && (tttv->indexer->indexResultType == indexResult);
     }
     else if (httv->indexer)
     {
-        result.indexer = httv->indexer;
+        if (!result.get())
+            result = std::make_unique<TableType>(TableType{state, level});
+        result->indexer = httv->indexer;
         thereSubHere = false;
     }
     else if (tttv->indexer)
     {
-        result.indexer = tttv->indexer;
+        if (!result.get())
+            result = std::make_unique<TableType>(TableType{state, level});
+        result->indexer = tttv->indexer;
         hereSubThere = false;
     }
 
@@ -2652,7 +2710,12 @@ std::optional<TypeId> Normalizer::intersectionOfTables(TypeId here, TypeId there
     else if (thereSubHere)
         table = ttable;
     else
-        table = arena->addType(std::move(result));
+    {
+        if (result.get())
+            table = arena->addType(std::move(*result));
+        else
+            table = arena->addType(TableType{state, level});
+    }
 
     if (tmtable && hmtable)
     {
@@ -3150,19 +3213,15 @@ NormalizationResult Normalizer::intersectNormalWithTy(NormalizedType& here, Type
         {
             if (fixNormalizeCaching())
             {
-                std::shared_ptr<const NormalizedType> normal = normalize(t);
+                NormalizationResult res = intersectNormalWithNegationTy(t, here);
-                std::optional<NormalizedType> negated = negateNormal(*normal);
+                if (shouldEarlyExit(res))
-                if (!negated)
+                    return res;
-                    return NormalizationResult::False;
-                intersectNormals(here, *negated);
             }
             else
             {
-                const NormalizedType* normal = DEPRECATED_normalize(t);
+                NormalizationResult res = intersectNormalWithNegationTy(t, here, /* useDeprecated */ true);
-                std::optional<NormalizedType> negated = negateNormal(*normal);
+                if (shouldEarlyExit(res))
-                if (!negated)
+                    return res;
-                    return NormalizationResult::False;
-                intersectNormals(here, *negated);
             }
         }
         else if (const UnionType* itv = get<UnionType>(t))
@@ -3171,11 +3230,9 @@ NormalizationResult Normalizer::intersectNormalWithTy(NormalizedType& here, Type
             {
                 for (TypeId part : itv->options)
                 {
-                    std::shared_ptr<const NormalizedType> normalPart = normalize(part);
+                    NormalizationResult res = intersectNormalWithNegationTy(part, here);
-                    std::optional<NormalizedType> negated = negateNormal(*normalPart);
+                    if (shouldEarlyExit(res))
-                    if (!negated)
+                        return res;
-                        return NormalizationResult::False;
-                    intersectNormals(here, *negated);
                 }
             }
             else
@@ -3184,22 +3241,18 @@ NormalizationResult Normalizer::intersectNormalWithTy(NormalizedType& here, Type
                 {
                     for (TypeId part : itv->options)
                     {
-                        std::shared_ptr<const NormalizedType> normalPart = normalize(part);
+                        NormalizationResult res = intersectNormalWithNegationTy(part, here);
-                        std::optional<NormalizedType> negated = negateNormal(*normalPart);
+                        if (shouldEarlyExit(res))
-                        if (!negated)
+                            return res;
-                            return NormalizationResult::False;
-                        intersectNormals(here, *negated);
                     }
                 }
                 else
                 {
                     for (TypeId part : itv->options)
                     {
-                        const NormalizedType* normalPart = DEPRECATED_normalize(part);
+                        NormalizationResult res = intersectNormalWithNegationTy(part, here, /* useDeprecated */ true);
-                        std::optional<NormalizedType> negated = negateNormal(*normalPart);
+                        if (shouldEarlyExit(res))
-                        if (!negated)
+                            return res;
-                            return NormalizationResult::False;
-                        intersectNormals(here, *negated);
                     }
                 }
             }

Analysis/src/TypeChecker2.cpp

@@ -1280,7 +1280,9 @@ struct TypeChecker2
 
     void visit(AstExprGlobal* expr)
     {
-        // TODO!
+        NotNull<Scope> scope = stack.back();
+        if (!scope->lookup(expr->name))
+            reportError(UnknownSymbol{expr->name.value, UnknownSymbol::Binding}, expr->location);
     }
 
     void visit(AstExprVarargs* expr)

CLI/Compile.cpp

@@ -317,6 +317,7 @@ static bool compileFile(const char* name, CompileFormat format, Luau::CodeGen::A
         {
             options.includeAssembly = format != CompileFormat::CodegenIr;
             options.includeIr = format != CompileFormat::CodegenAsm;
+            options.includeIrTypes = format != CompileFormat::CodegenAsm;
             options.includeOutlinedCode = format == CompileFormat::CodegenVerbose;
         }
 

CMakeLists.txt

@@ -229,6 +229,7 @@ if(LUAU_BUILD_TESTS)
     target_link_libraries(Luau.UnitTest PRIVATE Luau.Analysis Luau.Compiler Luau.CodeGen)
 
     target_compile_options(Luau.Conformance PRIVATE ${LUAU_OPTIONS})
+    target_compile_definitions(Luau.Conformance PRIVATE DOCTEST_CONFIG_DOUBLE_STRINGIFY)
     target_include_directories(Luau.Conformance PRIVATE extern)
     target_link_libraries(Luau.Conformance PRIVATE Luau.Analysis Luau.Compiler Luau.CodeGen Luau.VM)
     if(CMAKE_SYSTEM_NAME MATCHES "Android|iOS")

CodeGen/include/Luau/CodeGen.h

@@ -40,8 +40,12 @@ enum class CodeGenCompilationResult
     CodeGenAssemblerFinalizationFailure = 7,  // Failure during assembler finalization
     CodeGenLoweringFailure = 8,               // Lowering failed
     AllocationFailed = 9,                     // Native codegen failed due to an allocation error
+
+    Count = 10,
 };
 
+std::string toString(const CodeGenCompilationResult& result);
+
 struct ProtoCompilationFailure
 {
     CodeGenCompilationResult result = CodeGenCompilationResult::Success;

CodeGen/src/BytecodeAnalysis.cpp

@@ -6,6 +6,9 @@
 #include "Luau/IrUtils.h"
 
 #include "lobject.h"
+#include "lstate.h"
+
+#include <algorithm>
 
 #include <algorithm>
 
@@ -13,6 +16,7 @@ LUAU_FASTFLAG(LuauCodegenDirectUserdataFlow)
 LUAU_FASTFLAG(LuauLoadTypeInfo)                   // Because new VM typeinfo load changes the format used by Codegen, same flag is used
 LUAU_FASTFLAGVARIABLE(LuauCodegenTypeInfo, false) // New analysis is flagged separately
 LUAU_FASTFLAG(LuauTypeInfoLookupImprovement)
+LUAU_FASTFLAGVARIABLE(LuauCodegenVectorMispredictFix, false)
 
 namespace Luau
 {
@@ -771,10 +775,30 @@ void analyzeBytecodeTypes(IrFunction& function)
 
                 regTags[ra] = LBC_TYPE_ANY;
 
-                // Assuming that vector component is being indexed
+                if (FFlag::LuauCodegenVectorMispredictFix)
-                // TODO: check what key is used
+                {
-                if (bcType.a == LBC_TYPE_VECTOR)
+                    if (bcType.a == LBC_TYPE_VECTOR)
-                    regTags[ra] = LBC_TYPE_NUMBER;
+                    {
+                        TString* str = gco2ts(function.proto->k[kc].value.gc);
+                        const char* field = getstr(str);
+
+                        if (str->len == 1)
+                        {
+                            // Same handling as LOP_GETTABLEKS block in lvmexecute.cpp - case-insensitive comparison with "X" / "Y" / "Z"
+                            char ch = field[0] | ' ';
+
+                            if (ch == 'x' || ch == 'y' || ch == 'z')
+                                regTags[ra] = LBC_TYPE_NUMBER;
+                        }
+                    }
+                }
+                else
+                {
+                    // Assuming that vector component is being indexed
+                    // TODO: check what key is used
+                    if (bcType.a == LBC_TYPE_VECTOR)
+                        regTags[ra] = LBC_TYPE_NUMBER;
+                }
 
                 bcType.result = regTags[ra];
                 break;

CodeGen/src/CodeGen.cpp

@@ -65,6 +65,38 @@ namespace Luau
 namespace CodeGen
 {
 
+std::string toString(const CodeGenCompilationResult& result)
+{
+    switch (result)
+    {
+    case CodeGenCompilationResult::Success:
+        return "Success";
+    case CodeGenCompilationResult::NothingToCompile:
+        return "NothingToCompile";
+    case CodeGenCompilationResult::NotNativeModule:
+        return "NotNativeModule";
+    case CodeGenCompilationResult::CodeGenNotInitialized:
+        return "CodeGenNotInitialized";
+    case CodeGenCompilationResult::CodeGenOverflowInstructionLimit:
+        return "CodeGenOverflowInstructionLimit";
+    case CodeGenCompilationResult::CodeGenOverflowBlockLimit:
+        return "CodeGenOverflowBlockLimit";
+    case CodeGenCompilationResult::CodeGenOverflowBlockInstructionLimit:
+        return "CodeGenOverflowBlockInstructionLimit";
+    case CodeGenCompilationResult::CodeGenAssemblerFinalizationFailure:
+        return "CodeGenAssemblerFinalizationFailure";
+    case CodeGenCompilationResult::CodeGenLoweringFailure:
+        return "CodeGenLoweringFailure";
+    case CodeGenCompilationResult::AllocationFailed:
+        return "AllocationFailed";
+    case CodeGenCompilationResult::Count:
+        return "Count";
+    }
+
+    CODEGEN_ASSERT(false);
+    return "";
+}
+
 static const Instruction kCodeEntryInsn = LOP_NATIVECALL;
 
 void* gPerfLogContext = nullptr;

CodeGen/src/CodeGenAssembly.cpp

@@ -13,12 +13,55 @@
 #include "lapi.h"
 
 LUAU_FASTFLAG(LuauCodegenTypeInfo)
+LUAU_FASTFLAGVARIABLE(LuauCodegenIrTypeNames, false)
 
 namespace Luau
 {
 namespace CodeGen
 {
 
+static const LocVar* tryFindLocal(const Proto* proto, int reg, int pcpos)
+{
+    CODEGEN_ASSERT(FFlag::LuauCodegenIrTypeNames);
+
+    for (int i = 0; i < proto->sizelocvars; i++)
+    {
+        const LocVar& local = proto->locvars[i];
+
+        if (reg == local.reg && pcpos >= local.startpc && pcpos < local.endpc)
+            return &local;
+    }
+
+    return nullptr;
+}
+
+const char* tryFindLocalName(const Proto* proto, int reg, int pcpos)
+{
+    CODEGEN_ASSERT(FFlag::LuauCodegenIrTypeNames);
+
+    const LocVar* var = tryFindLocal(proto, reg, pcpos);
+
+    if (var && var->varname)
+        return getstr(var->varname);
+
+    return nullptr;
+}
+
+const char* tryFindUpvalueName(const Proto* proto, int upval)
+{
+    CODEGEN_ASSERT(FFlag::LuauCodegenIrTypeNames);
+
+    if (proto->upvalues)
+    {
+        CODEGEN_ASSERT(upval < proto->sizeupvalues);
+
+        if (proto->upvalues[upval])
+            return getstr(proto->upvalues[upval]);
+    }
+
+    return nullptr;
+}
+
 template<typename AssemblyBuilder>
 static void logFunctionHeader(AssemblyBuilder& build, Proto* proto)
 {
@@ -29,12 +72,22 @@ static void logFunctionHeader(AssemblyBuilder& build, Proto* proto)
 
     for (int i = 0; i < proto->numparams; i++)
     {
-        LocVar* var = proto->locvars ? &proto->locvars[proto->sizelocvars - proto->numparams + i] : nullptr;
+        if (FFlag::LuauCodegenIrTypeNames)
-
+        {
-        if (var && var->varname)
+            if (const char* name = tryFindLocalName(proto, i, 0))
-            build.logAppend("%s%s", i == 0 ? "" : ", ", getstr(var->varname));
+                build.logAppend("%s%s", i == 0 ? "" : ", ", name);
+            else
+                build.logAppend("%s$arg%d", i == 0 ? "" : ", ", i);
+        }
         else
-            build.logAppend("%s$arg%d", i == 0 ? "" : ", ", i);
+        {
+            LocVar* var = proto->locvars ? &proto->locvars[proto->sizelocvars - proto->numparams + i] : nullptr;
+
+            if (var && var->varname)
+                build.logAppend("%s%s", i == 0 ? "" : ", ", getstr(var->varname));
+            else
+                build.logAppend("%s$arg%d", i == 0 ? "" : ", ", i);
+        }
     }
 
     if (proto->numparams != 0 && proto->is_vararg)
@@ -59,21 +112,58 @@ static void logFunctionTypes(AssemblyBuilder& build, const IrFunction& function)
     {
         uint8_t ty = typeInfo.argumentTypes[i];
 
-        if (ty != LBC_TYPE_ANY)
+        if (FFlag::LuauCodegenIrTypeNames)
-            build.logAppend("; R%d: %s [argument]\n", int(i), getBytecodeTypeName(ty));
+        {
+            if (ty != LBC_TYPE_ANY)
+            {
+                if (const char* name = tryFindLocalName(function.proto, int(i), 0))
+                    build.logAppend("; R%d: %s [argument '%s']\n", int(i), getBytecodeTypeName(ty), name);
+                else
+                    build.logAppend("; R%d: %s [argument]\n", int(i), getBytecodeTypeName(ty));
+            }
+        }
+        else
+        {
+            if (ty != LBC_TYPE_ANY)
+                build.logAppend("; R%d: %s [argument]\n", int(i), getBytecodeTypeName(ty));
+        }
     }
 
     for (size_t i = 0; i < typeInfo.upvalueTypes.size(); i++)
     {
         uint8_t ty = typeInfo.upvalueTypes[i];
 
-        if (ty != LBC_TYPE_ANY)
+        if (FFlag::LuauCodegenIrTypeNames)
-            build.logAppend("; U%d: %s\n", int(i), getBytecodeTypeName(ty));
+        {
+            if (ty != LBC_TYPE_ANY)
+            {
+                if (const char* name = tryFindUpvalueName(function.proto, int(i)))
+                    build.logAppend("; U%d: %s ['%s']\n", int(i), getBytecodeTypeName(ty), name);
+                else
+                    build.logAppend("; U%d: %s\n", int(i), getBytecodeTypeName(ty));
+            }
+        }
+        else
+        {
+            if (ty != LBC_TYPE_ANY)
+                build.logAppend("; U%d: %s\n", int(i), getBytecodeTypeName(ty));
+        }
     }
 
     for (const BytecodeRegTypeInfo& el : typeInfo.regTypes)
     {
-        build.logAppend("; R%d: %s from %d to %d\n", el.reg, getBytecodeTypeName(el.type), el.startpc, el.endpc);
+        if (FFlag::LuauCodegenIrTypeNames)
+        {
+            // Using last active position as the PC because 'startpc' for type info is before local is initialized
+            if (const char* name = tryFindLocalName(function.proto, el.reg, el.endpc - 1))
+                build.logAppend("; R%d: %s from %d to %d [local '%s']\n", el.reg, getBytecodeTypeName(el.type), el.startpc, el.endpc, name);
+            else
+                build.logAppend("; R%d: %s from %d to %d\n", el.reg, getBytecodeTypeName(el.type), el.startpc, el.endpc);
+        }
+        else
+        {
+            build.logAppend("; R%d: %s from %d to %d\n", el.reg, getBytecodeTypeName(el.type), el.startpc, el.endpc);
+        }
     }
 }
 

CodeGen/src/IrTranslation.cpp

@@ -13,6 +13,7 @@
 #include "ltm.h"
 
 LUAU_FASTFLAGVARIABLE(LuauCodegenDirectUserdataFlow, false)
+LUAU_FASTFLAGVARIABLE(LuauCodegenFixVectorFields, false)
 
 namespace Luau
 {
@@ -1197,19 +1198,19 @@ void translateInstGetTableKS(IrBuilder& build, const Instruction* pc, int pcpos)
         TString* str = gco2ts(build.function.proto->k[aux].value.gc);
         const char* field = getstr(str);
 
-        if (*field == 'X' || *field == 'x')
+        if ((!FFlag::LuauCodegenFixVectorFields || str->len == 1) && (*field == 'X' || *field == 'x'))
         {
             IrOp value = build.inst(IrCmd::LOAD_FLOAT, build.vmReg(rb), build.constInt(0));
             build.inst(IrCmd::STORE_DOUBLE, build.vmReg(ra), value);
             build.inst(IrCmd::STORE_TAG, build.vmReg(ra), build.constTag(LUA_TNUMBER));
         }
-        else if (*field == 'Y' || *field == 'y')
+        else if ((!FFlag::LuauCodegenFixVectorFields || str->len == 1) && (*field == 'Y' || *field == 'y'))
         {
             IrOp value = build.inst(IrCmd::LOAD_FLOAT, build.vmReg(rb), build.constInt(4));
             build.inst(IrCmd::STORE_DOUBLE, build.vmReg(ra), value);
             build.inst(IrCmd::STORE_TAG, build.vmReg(ra), build.constTag(LUA_TNUMBER));
         }
-        else if (*field == 'Z' || *field == 'z')
+        else if ((!FFlag::LuauCodegenFixVectorFields || str->len == 1) && (*field == 'Z' || *field == 'z'))
         {
             IrOp value = build.inst(IrCmd::LOAD_FLOAT, build.vmReg(rb), build.constInt(8));
             build.inst(IrCmd::STORE_DOUBLE, build.vmReg(ra), value);

Compiler/src/Builtins.cpp

@@ -454,7 +454,7 @@ BuiltinInfo getBuiltinInfo(int bfid)
     case LBF_BUFFER_WRITEF32:
     case LBF_BUFFER_WRITEF64:
         return {3, 0, BuiltinInfo::Flag_NoneSafe};
-    };
+    }
 
     LUAU_UNREACHABLE();
 }

Compiler/src/Compiler.cpp

@@ -29,6 +29,7 @@ LUAU_FASTINTVARIABLE(LuauCompileInlineDepth, 5)
 LUAU_FASTFLAGVARIABLE(LuauCompileRepeatUntilSkippedLocals, false)
 LUAU_FASTFLAG(LuauCompileTypeInfo)
 LUAU_FASTFLAGVARIABLE(LuauTypeInfoLookupImprovement, false)
+LUAU_FASTFLAGVARIABLE(LuauCompileTempTypeInfo, false)
 
 namespace Luau
 {
@@ -108,6 +109,8 @@ struct Compiler
         , builtins(nullptr)
         , functionTypes(nullptr)
         , localTypes(nullptr)
+        , exprTypes(nullptr)
+        , builtinTypes(options.vectorType)
     {
         // preallocate some buffers that are very likely to grow anyway; this works around std::vector's inefficient growth policy for small arrays
         localStack.reserve(16);
@@ -916,6 +919,9 @@ struct Compiler
 
             bytecode.emitABC(LOP_NAMECALL, regs, selfreg, uint8_t(BytecodeBuilder::getStringHash(iname)));
             bytecode.emitAux(cid);
+
+            if (FFlag::LuauCompileTempTypeInfo)
+                hintTemporaryExprRegType(fi->expr, selfreg, LBC_TYPE_TABLE, /* instLength */ 2);
         }
         else if (bfid >= 0)
         {
@@ -1570,6 +1576,9 @@ struct Compiler
                 uint8_t rl = compileExprAuto(expr->left, rs);
 
                 bytecode.emitABC(getBinaryOpArith(expr->op, /* k= */ true), target, rl, uint8_t(rc));
+
+                if (FFlag::LuauCompileTempTypeInfo)
+                    hintTemporaryExprRegType(expr->left, rl, LBC_TYPE_NUMBER, /* instLength */ 1);
             }
             else
             {
@@ -1583,6 +1592,9 @@ struct Compiler
                         LuauOpcode op = (expr->op == AstExprBinary::Sub) ? LOP_SUBRK : LOP_DIVRK;
 
                         bytecode.emitABC(op, target, uint8_t(lc), uint8_t(rr));
+
+                        if (FFlag::LuauCompileTempTypeInfo)
+                            hintTemporaryExprRegType(expr->right, rr, LBC_TYPE_NUMBER, /* instLength */ 1);
                         return;
                     }
                 }
@@ -1591,6 +1603,12 @@ struct Compiler
                 uint8_t rr = compileExprAuto(expr->right, rs);
 
                 bytecode.emitABC(getBinaryOpArith(expr->op), target, rl, rr);
+
+                if (FFlag::LuauCompileTempTypeInfo)
+                {
+                    hintTemporaryExprRegType(expr->left, rl, LBC_TYPE_NUMBER, /* instLength */ 1);
+                    hintTemporaryExprRegType(expr->right, rr, LBC_TYPE_NUMBER, /* instLength */ 1);
+                }
             }
         }
         break;
@@ -2030,6 +2048,9 @@ struct Compiler
 
         bytecode.emitABC(LOP_GETTABLEKS, target, reg, uint8_t(BytecodeBuilder::getStringHash(iname)));
         bytecode.emitAux(cid);
+
+        if (FFlag::LuauCompileTempTypeInfo)
+            hintTemporaryExprRegType(expr->expr, reg, LBC_TYPE_TABLE, /* instLength */ 2);
     }
 
     void compileExprIndexExpr(AstExprIndexExpr* expr, uint8_t target)
@@ -3410,6 +3431,14 @@ struct Compiler
                 uint8_t rr = compileExprAuto(stat->value, rs);
 
                 bytecode.emitABC(getBinaryOpArith(stat->op), target, target, rr);
+
+                if (FFlag::LuauCompileTempTypeInfo)
+                {
+                    if (var.kind != LValue::Kind_Local)
+                        hintTemporaryRegType(stat->var, target, LBC_TYPE_NUMBER, /* instLength */ 1);
+
+                    hintTemporaryExprRegType(stat->value, rr, LBC_TYPE_NUMBER, /* instLength */ 1);
+                }
             }
         }
         break;
@@ -3794,6 +3823,27 @@ struct Compiler
         return !node->is<AstStatBlock>() && !node->is<AstStatTypeAlias>();
     }
 
+    void hintTemporaryRegType(AstExpr* expr, int reg, LuauBytecodeType expectedType, int instLength)
+    {
+        LUAU_ASSERT(FFlag::LuauCompileTempTypeInfo);
+
+        // If we know the type of a temporary and it's not the type that would be expected by codegen, provide a hint
+        if (LuauBytecodeType* ty = exprTypes.find(expr))
+        {
+            if (*ty != expectedType)
+                bytecode.pushLocalTypeInfo(*ty, reg, bytecode.getDebugPC() - instLength, bytecode.getDebugPC());
+        }
+    }
+
+    void hintTemporaryExprRegType(AstExpr* expr, int reg, LuauBytecodeType expectedType, int instLength)
+    {
+        LUAU_ASSERT(FFlag::LuauCompileTempTypeInfo);
+
+        // If we allocated a temporary register for the operation argument, try hinting its type
+        if (!getExprLocal(expr))
+            hintTemporaryRegType(expr, reg, expectedType, instLength);
+    }
+
     struct FenvVisitor : AstVisitor
     {
         bool& getfenvUsed;
@@ -4046,6 +4096,9 @@ struct Compiler
     DenseHashMap<AstExprCall*, int> builtins;
     DenseHashMap<AstExprFunction*, std::string> functionTypes;
     DenseHashMap<AstLocal*, LuauBytecodeType> localTypes;
+    DenseHashMap<AstExpr*, LuauBytecodeType> exprTypes;
+
+    BuiltinTypes builtinTypes;
 
     const DenseHashMap<AstExprCall*, int>* builtinsFold = nullptr;
     bool builtinsFoldMathK = false;
@@ -4141,12 +4194,14 @@ void compileOrThrow(BytecodeBuilder& bytecode, const ParseResult& parseResult, c
     if (FFlag::LuauCompileTypeInfo)
     {
         if (options.typeInfoLevel >= 1)
-            buildTypeMap(compiler.functionTypes, compiler.localTypes, root, options.vectorType);
+            buildTypeMap(compiler.functionTypes, compiler.localTypes, compiler.exprTypes, root, options.vectorType, compiler.builtinTypes,
+                compiler.builtins, compiler.globals);
     }
     else
     {
         if (functionVisitor.hasTypes)
-            buildTypeMap(compiler.functionTypes, compiler.localTypes, root, options.vectorType);
+            buildTypeMap(compiler.functionTypes, compiler.localTypes, compiler.exprTypes, root, options.vectorType, compiler.builtinTypes,
+                compiler.builtins, compiler.globals);
     }
 
     for (AstExprFunction* expr : functions)

Compiler/src/Types.cpp

@@ -4,6 +4,7 @@
 #include "Luau/BytecodeBuilder.h"
 
 LUAU_FASTFLAG(LuauCompileTypeInfo)
+LUAU_FASTFLAG(LuauCompileTempTypeInfo)
 
 namespace Luau
 {
@@ -37,10 +38,10 @@ static LuauBytecodeType getPrimitiveType(AstName name)
         return LBC_TYPE_INVALID;
 }
 
-static LuauBytecodeType getType(AstType* ty, const AstArray<AstGenericType>& generics, const DenseHashMap<AstName, AstStatTypeAlias*>& typeAliases,
+static LuauBytecodeType getType(const AstType* ty, const AstArray<AstGenericType>& generics,
-    bool resolveAliases, const char* vectorType)
+    const DenseHashMap<AstName, AstStatTypeAlias*>& typeAliases, bool resolveAliases, const char* vectorType)
 {
-    if (AstTypeReference* ref = ty->as<AstTypeReference>())
+    if (const AstTypeReference* ref = ty->as<AstTypeReference>())
     {
         if (ref->prefix)
             return LBC_TYPE_ANY;
@@ -66,15 +67,15 @@ static LuauBytecodeType getType(AstType* ty, const AstArray<AstGenericType>& gen
         // not primitive or alias or generic => host-provided, we assume userdata for now
         return LBC_TYPE_USERDATA;
     }
-    else if (AstTypeTable* table = ty->as<AstTypeTable>())
+    else if (const AstTypeTable* table = ty->as<AstTypeTable>())
     {
         return LBC_TYPE_TABLE;
     }
-    else if (AstTypeFunction* func = ty->as<AstTypeFunction>())
+    else if (const AstTypeFunction* func = ty->as<AstTypeFunction>())
     {
         return LBC_TYPE_FUNCTION;
     }
-    else if (AstTypeUnion* un = ty->as<AstTypeUnion>())
+    else if (const AstTypeUnion* un = ty->as<AstTypeUnion>())
     {
         bool optional = false;
         LuauBytecodeType type = LBC_TYPE_INVALID;
@@ -104,7 +105,7 @@ static LuauBytecodeType getType(AstType* ty, const AstArray<AstGenericType>& gen
 
         return LuauBytecodeType(type | (optional && (type != LBC_TYPE_ANY) ? LBC_TYPE_OPTIONAL_BIT : 0));
     }
-    else if (AstTypeIntersection* inter = ty->as<AstTypeIntersection>())
+    else if (const AstTypeIntersection* inter = ty->as<AstTypeIntersection>())
     {
         return LBC_TYPE_ANY;
     }
@@ -144,21 +145,44 @@ static std::string getFunctionType(const AstExprFunction* func, const DenseHashM
     return typeInfo;
 }
 
+static bool isMatchingGlobal(const DenseHashMap<AstName, Compile::Global>& globals, AstExpr* node, const char* name)
+{
+    LUAU_ASSERT(FFlag::LuauCompileTempTypeInfo);
+
+    if (AstExprGlobal* expr = node->as<AstExprGlobal>())
+        return Compile::getGlobalState(globals, expr->name) == Compile::Global::Default && expr->name == name;
+
+    return false;
+}
+
 struct TypeMapVisitor : AstVisitor
 {
     DenseHashMap<AstExprFunction*, std::string>& functionTypes;
     DenseHashMap<AstLocal*, LuauBytecodeType>& localTypes;
+    DenseHashMap<AstExpr*, LuauBytecodeType>& exprTypes;
     const char* vectorType;
+    const BuiltinTypes& builtinTypes;
+    const DenseHashMap<AstExprCall*, int>& builtinCalls;
+    const DenseHashMap<AstName, Compile::Global>& globals;
 
     DenseHashMap<AstName, AstStatTypeAlias*> typeAliases;
     std::vector<std::pair<AstName, AstStatTypeAlias*>> typeAliasStack;
+    DenseHashMap<AstLocal*, const AstType*> resolvedLocals;
+    DenseHashMap<AstExpr*, const AstType*> resolvedExprs;
 
-    TypeMapVisitor(
+    TypeMapVisitor(DenseHashMap<AstExprFunction*, std::string>& functionTypes, DenseHashMap<AstLocal*, LuauBytecodeType>& localTypes,
-        DenseHashMap<AstExprFunction*, std::string>& functionTypes, DenseHashMap<AstLocal*, LuauBytecodeType>& localTypes, const char* vectorType)
+        DenseHashMap<AstExpr*, LuauBytecodeType>& exprTypes, const char* vectorType, const BuiltinTypes& builtinTypes,
+        const DenseHashMap<AstExprCall*, int>& builtinCalls, const DenseHashMap<AstName, Compile::Global>& globals)
         : functionTypes(functionTypes)
         , localTypes(localTypes)
+        , exprTypes(exprTypes)
         , vectorType(vectorType)
+        , builtinTypes(builtinTypes)
+        , builtinCalls(builtinCalls)
+        , globals(globals)
         , typeAliases(AstName())
+        , resolvedLocals(nullptr)
+        , resolvedExprs(nullptr)
     {
     }
 
@@ -189,6 +213,64 @@ struct TypeMapVisitor : AstVisitor
         }
     }
 
+    const AstType* resolveAliases(const AstType* ty)
+    {
+        LUAU_ASSERT(FFlag::LuauCompileTempTypeInfo);
+
+        if (const AstTypeReference* ref = ty->as<AstTypeReference>())
+        {
+            if (ref->prefix)
+                return ty;
+
+            if (AstStatTypeAlias* const* alias = typeAliases.find(ref->name); alias && *alias)
+                return (*alias)->type;
+        }
+
+        return ty;
+    }
+
+    const AstTableIndexer* tryGetTableIndexer(AstExpr* expr)
+    {
+        LUAU_ASSERT(FFlag::LuauCompileTempTypeInfo);
+
+        if (const AstType** typePtr = resolvedExprs.find(expr))
+        {
+            if (const AstTypeTable* tableTy = (*typePtr)->as<AstTypeTable>())
+                return tableTy->indexer;
+        }
+
+        return nullptr;
+    }
+
+    LuauBytecodeType recordResolvedType(AstExpr* expr, const AstType* ty)
+    {
+        LUAU_ASSERT(FFlag::LuauCompileTempTypeInfo);
+
+        ty = resolveAliases(ty);
+
+        resolvedExprs[expr] = ty;
+
+        LuauBytecodeType bty = getType(ty, {}, typeAliases, /* resolveAliases= */ true, vectorType);
+        exprTypes[expr] = bty;
+        return bty;
+    }
+
+    LuauBytecodeType recordResolvedType(AstLocal* local, const AstType* ty)
+    {
+        LUAU_ASSERT(FFlag::LuauCompileTempTypeInfo);
+
+        ty = resolveAliases(ty);
+
+        resolvedLocals[local] = ty;
+
+        LuauBytecodeType bty = getType(ty, {}, typeAliases, /* resolveAliases= */ true, vectorType);
+
+        if (bty != LBC_TYPE_ANY)
+            localTypes[local] = bty;
+
+        return bty;
+    }
+
     bool visit(AstStatBlock* node) override
     {
         size_t aliasStackTop = pushTypeAliases(node);
@@ -216,6 +298,60 @@ struct TypeMapVisitor : AstVisitor
         return false;
     }
 
+    // for...in statement can contain type annotations on locals (we might even infer some for ipairs/pairs/generalized iteration)
+    bool visit(AstStatForIn* node) override
+    {
+        if (!FFlag::LuauCompileTempTypeInfo)
+            return true;
+
+        for (AstExpr* expr : node->values)
+            expr->visit(this);
+
+        // This is similar to how Compiler matches builtin iteration, but we also handle generalized iteration case
+        if (node->vars.size == 2 && node->values.size == 1)
+        {
+            if (AstExprCall* call = node->values.data[0]->as<AstExprCall>(); call && call->args.size == 1)
+            {
+                AstExpr* func = call->func;
+                AstExpr* arg = call->args.data[0];
+
+                if (isMatchingGlobal(globals, func, "ipairs"))
+                {
+                    if (const AstTableIndexer* indexer = tryGetTableIndexer(arg))
+                    {
+                        recordResolvedType(node->vars.data[0], &builtinTypes.numberType);
+                        recordResolvedType(node->vars.data[1], indexer->resultType);
+                    }
+                }
+                else if (isMatchingGlobal(globals, func, "pairs"))
+                {
+                    if (const AstTableIndexer* indexer = tryGetTableIndexer(arg))
+                    {
+                        recordResolvedType(node->vars.data[0], indexer->indexType);
+                        recordResolvedType(node->vars.data[1], indexer->resultType);
+                    }
+                }
+            }
+            else if (const AstTableIndexer* indexer = tryGetTableIndexer(node->values.data[0]))
+            {
+                recordResolvedType(node->vars.data[0], indexer->indexType);
+                recordResolvedType(node->vars.data[1], indexer->resultType);
+            }
+        }
+
+        for (size_t i = 0; i < node->vars.size; i++)
+        {
+            AstLocal* var = node->vars.data[i];
+
+            if (AstType* annotation = var->annotation)
+                recordResolvedType(var, annotation);
+        }
+
+        node->body->visit(this);
+
+        return false;
+    }
+
     bool visit(AstExprFunction* node) override
     {
         std::string type = getFunctionType(node, typeAliases, vectorType);
@@ -223,32 +359,405 @@ struct TypeMapVisitor : AstVisitor
         if (!type.empty())
             functionTypes[node] = std::move(type);
 
-        return true;
+        return true; // Let generic visitor step into all expressions
     }
 
     bool visit(AstExprLocal* node) override
     {
-        if (FFlag::LuauCompileTypeInfo)
+        if (FFlag::LuauCompileTempTypeInfo)
         {
-            AstLocal* local = node->local;
+            if (FFlag::LuauCompileTypeInfo)
-
-            if (AstType* annotation = local->annotation)
             {
-                LuauBytecodeType ty = getType(annotation, {}, typeAliases, /* resolveAliases= */ true, vectorType);
+                AstLocal* local = node->local;
 
-                if (ty != LBC_TYPE_ANY)
+                if (AstType* annotation = local->annotation)
-                    localTypes[local] = ty;
+                {
+                    LuauBytecodeType ty = recordResolvedType(node, annotation);
+
+                    if (ty != LBC_TYPE_ANY)
+                        localTypes[local] = ty;
+                }
+                else if (const AstType** typePtr = resolvedLocals.find(local))
+                {
+                    localTypes[local] = recordResolvedType(node, *typePtr);
+                }
+            }
+
+            return false;
+        }
+        else
+        {
+            if (FFlag::LuauCompileTypeInfo)
+            {
+                AstLocal* local = node->local;
+
+                if (AstType* annotation = local->annotation)
+                {
+                    LuauBytecodeType ty = getType(annotation, {}, typeAliases, /* resolveAliases= */ true, vectorType);
+
+                    if (ty != LBC_TYPE_ANY)
+                        localTypes[local] = ty;
+                }
+            }
+
+            return true;
+        }
+    }
+
+    bool visit(AstStatLocal* node) override
+    {
+        if (!FFlag::LuauCompileTempTypeInfo)
+            return true;
+
+        for (AstExpr* expr : node->values)
+            expr->visit(this);
+
+        for (size_t i = 0; i < node->vars.size; i++)
+        {
+            AstLocal* var = node->vars.data[i];
+
+            // Propagate from the value that's being assigned
+            // This simple propagation doesn't handle type packs in tail position
+            if (var->annotation == nullptr)
+            {
+                if (i < node->values.size)
+                {
+                    if (const AstType** typePtr = resolvedExprs.find(node->values.data[i]))
+                        resolvedLocals[var] = *typePtr;
+                }
             }
         }
 
-        return true;
+        return false;
     }
+
+    bool visit(AstExprIndexExpr* node) override
+    {
+        if (!FFlag::LuauCompileTempTypeInfo)
+            return true;
+
+        node->expr->visit(this);
+        node->index->visit(this);
+
+        if (const AstTableIndexer* indexer = tryGetTableIndexer(node->expr))
+            recordResolvedType(node, indexer->resultType);
+
+        return false;
+    }
+
+    bool visit(AstExprIndexName* node) override
+    {
+        if (!FFlag::LuauCompileTempTypeInfo)
+            return true;
+
+        node->expr->visit(this);
+
+        if (const AstType** typePtr = resolvedExprs.find(node->expr))
+        {
+            if (const AstTypeTable* tableTy = (*typePtr)->as<AstTypeTable>())
+            {
+                for (const AstTableProp& prop : tableTy->props)
+                {
+                    if (prop.name == node->index)
+                    {
+                        recordResolvedType(node, prop.type);
+                        return false;
+                    }
+                }
+            }
+        }
+
+        if (LuauBytecodeType* typeBcPtr = exprTypes.find(node->expr))
+        {
+            if (*typeBcPtr == LBC_TYPE_VECTOR)
+            {
+                if (node->index == "X" || node->index == "Y" || node->index == "Z")
+                    recordResolvedType(node, &builtinTypes.numberType);
+            }
+        }
+
+        return false;
+    }
+
+    bool visit(AstExprUnary* node) override
+    {
+        if (!FFlag::LuauCompileTempTypeInfo)
+            return true;
+
+        node->expr->visit(this);
+
+        switch (node->op)
+        {
+        case AstExprUnary::Not:
+            recordResolvedType(node, &builtinTypes.booleanType);
+            break;
+        case AstExprUnary::Minus:
+        {
+            const AstType** typePtr = resolvedExprs.find(node->expr);
+            LuauBytecodeType* bcTypePtr = exprTypes.find(node->expr);
+
+            if (!typePtr || !bcTypePtr)
+                return false;
+
+            if (*bcTypePtr == LBC_TYPE_VECTOR)
+                recordResolvedType(node, *typePtr);
+            else if (*bcTypePtr == LBC_TYPE_NUMBER)
+                recordResolvedType(node, *typePtr);
+
+            break;
+        }
+        case AstExprUnary::Len:
+            recordResolvedType(node, &builtinTypes.numberType);
+            break;
+        }
+
+        return false;
+    }
+
+    bool visit(AstExprBinary* node) override
+    {
+        if (!FFlag::LuauCompileTempTypeInfo)
+            return true;
+
+        node->left->visit(this);
+        node->right->visit(this);
+
+        // Comparisons result in a boolean
+        if (node->op == AstExprBinary::CompareNe || node->op == AstExprBinary::CompareEq || node->op == AstExprBinary::CompareLt ||
+            node->op == AstExprBinary::CompareLe || node->op == AstExprBinary::CompareGt || node->op == AstExprBinary::CompareGe)
+        {
+            recordResolvedType(node, &builtinTypes.booleanType);
+            return false;
+        }
+
+        if (node->op == AstExprBinary::Concat || node->op == AstExprBinary::And || node->op == AstExprBinary::Or)
+            return false;
+
+        const AstType** leftTypePtr = resolvedExprs.find(node->left);
+        LuauBytecodeType* leftBcTypePtr = exprTypes.find(node->left);
+
+        if (!leftTypePtr || !leftBcTypePtr)
+            return false;
+
+        const AstType** rightTypePtr = resolvedExprs.find(node->right);
+        LuauBytecodeType* rightBcTypePtr = exprTypes.find(node->right);
+
+        if (!rightTypePtr || !rightBcTypePtr)
+            return false;
+
+        if (*leftBcTypePtr == LBC_TYPE_VECTOR)
+            recordResolvedType(node, *leftTypePtr);
+        else if (*rightBcTypePtr == LBC_TYPE_VECTOR)
+            recordResolvedType(node, *rightTypePtr);
+        else if (*leftBcTypePtr == LBC_TYPE_NUMBER && *rightBcTypePtr == LBC_TYPE_NUMBER)
+            recordResolvedType(node, *leftTypePtr);
+
+        return false;
+    }
+
+    bool visit(AstExprGroup* node) override
+    {
+        if (!FFlag::LuauCompileTempTypeInfo)
+            return true;
+
+        node->expr->visit(this);
+
+        if (const AstType** typePtr = resolvedExprs.find(node->expr))
+            recordResolvedType(node, *typePtr);
+
+        return false;
+    }
+
+    bool visit(AstExprTypeAssertion* node) override
+    {
+        if (!FFlag::LuauCompileTempTypeInfo)
+            return true;
+
+        node->expr->visit(this);
+
+        recordResolvedType(node, node->annotation);
+
+        return false;
+    }
+
+    bool visit(AstExprConstantBool* node) override
+    {
+        if (!FFlag::LuauCompileTempTypeInfo)
+            return true;
+
+        recordResolvedType(node, &builtinTypes.booleanType);
+
+        return false;
+    }
+
+    bool visit(AstExprConstantNumber* node) override
+    {
+        if (!FFlag::LuauCompileTempTypeInfo)
+            return true;
+
+        recordResolvedType(node, &builtinTypes.numberType);
+
+        return false;
+    }
+
+    bool visit(AstExprConstantString* node) override
+    {
+        if (!FFlag::LuauCompileTempTypeInfo)
+            return true;
+
+        recordResolvedType(node, &builtinTypes.stringType);
+
+        return false;
+    }
+
+    bool visit(AstExprInterpString* node) override
+    {
+        if (!FFlag::LuauCompileTempTypeInfo)
+            return true;
+
+        recordResolvedType(node, &builtinTypes.stringType);
+
+        return false;
+    }
+
+    bool visit(AstExprIfElse* node) override
+    {
+        if (!FFlag::LuauCompileTempTypeInfo)
+            return true;
+
+        node->condition->visit(this);
+        node->trueExpr->visit(this);
+        node->falseExpr->visit(this);
+
+        const AstType** trueTypePtr = resolvedExprs.find(node->trueExpr);
+        LuauBytecodeType* trueBcTypePtr = exprTypes.find(node->trueExpr);
+        LuauBytecodeType* falseBcTypePtr = exprTypes.find(node->falseExpr);
+
+        // Optimistic check that both expressions are of the same kind, as AstType* cannot be compared
+        if (trueTypePtr && trueBcTypePtr && falseBcTypePtr && *trueBcTypePtr == *falseBcTypePtr)
+            recordResolvedType(node, *trueTypePtr);
+
+        return false;
+    }
+
+    bool visit(AstExprCall* node) override
+    {
+        if (!FFlag::LuauCompileTempTypeInfo)
+            return true;
+
+        if (const int* bfid = builtinCalls.find(node))
+        {
+            switch (LuauBuiltinFunction(*bfid))
+            {
+            case LBF_NONE:
+            case LBF_ASSERT:
+            case LBF_RAWSET:
+            case LBF_RAWGET:
+            case LBF_TABLE_INSERT:
+            case LBF_TABLE_UNPACK:
+            case LBF_SELECT_VARARG:
+            case LBF_GETMETATABLE:
+            case LBF_SETMETATABLE:
+            case LBF_BUFFER_WRITEU8:
+            case LBF_BUFFER_WRITEU16:
+            case LBF_BUFFER_WRITEU32:
+            case LBF_BUFFER_WRITEF32:
+            case LBF_BUFFER_WRITEF64:
+                break;
+            case LBF_MATH_ABS:
+            case LBF_MATH_ACOS:
+            case LBF_MATH_ASIN:
+            case LBF_MATH_ATAN2:
+            case LBF_MATH_ATAN:
+            case LBF_MATH_CEIL:
+            case LBF_MATH_COSH:
+            case LBF_MATH_COS:
+            case LBF_MATH_DEG:
+            case LBF_MATH_EXP:
+            case LBF_MATH_FLOOR:
+            case LBF_MATH_FMOD:
+            case LBF_MATH_FREXP:
+            case LBF_MATH_LDEXP:
+            case LBF_MATH_LOG10:
+            case LBF_MATH_LOG:
+            case LBF_MATH_MAX:
+            case LBF_MATH_MIN:
+            case LBF_MATH_MODF:
+            case LBF_MATH_POW:
+            case LBF_MATH_RAD:
+            case LBF_MATH_SINH:
+            case LBF_MATH_SIN:
+            case LBF_MATH_SQRT:
+            case LBF_MATH_TANH:
+            case LBF_MATH_TAN:
+            case LBF_BIT32_ARSHIFT:
+            case LBF_BIT32_BAND:
+            case LBF_BIT32_BNOT:
+            case LBF_BIT32_BOR:
+            case LBF_BIT32_BXOR:
+            case LBF_BIT32_BTEST:
+            case LBF_BIT32_EXTRACT:
+            case LBF_BIT32_LROTATE:
+            case LBF_BIT32_LSHIFT:
+            case LBF_BIT32_REPLACE:
+            case LBF_BIT32_RROTATE:
+            case LBF_BIT32_RSHIFT:
+            case LBF_STRING_BYTE:
+            case LBF_STRING_LEN:
+            case LBF_MATH_CLAMP:
+            case LBF_MATH_SIGN:
+            case LBF_MATH_ROUND:
+            case LBF_BIT32_COUNTLZ:
+            case LBF_BIT32_COUNTRZ:
+            case LBF_RAWLEN:
+            case LBF_BIT32_EXTRACTK:
+            case LBF_TONUMBER:
+            case LBF_BIT32_BYTESWAP:
+            case LBF_BUFFER_READI8:
+            case LBF_BUFFER_READU8:
+            case LBF_BUFFER_READI16:
+            case LBF_BUFFER_READU16:
+            case LBF_BUFFER_READI32:
+            case LBF_BUFFER_READU32:
+            case LBF_BUFFER_READF32:
+            case LBF_BUFFER_READF64:
+                recordResolvedType(node, &builtinTypes.numberType);
+                break;
+
+            case LBF_TYPE:
+            case LBF_STRING_CHAR:
+            case LBF_TYPEOF:
+            case LBF_STRING_SUB:
+            case LBF_TOSTRING:
+                recordResolvedType(node, &builtinTypes.stringType);
+                break;
+
+            case LBF_RAWEQUAL:
+                recordResolvedType(node, &builtinTypes.booleanType);
+                break;
+
+            case LBF_VECTOR:
+                recordResolvedType(node, &builtinTypes.vectorType);
+                break;
+            }
+        }
+
+        return true; // Let generic visitor step into all expressions
+    }
+
+    // AstExpr classes that are not covered:
+    // * AstExprConstantNil is not resolved to 'nil' because that doesn't help codegen operations and often used as an initializer before real value
+    // * AstExprGlobal is not supported as we don't have info on globals
+    // * AstExprVarargs cannot be resolved to a testable type
+    // * AstExprTable cannot be reconstructed into a specific AstTypeTable and table annotations don't really help codegen
+    // * AstExprCall is very complex (especially if builtins and registered globals are included), will be extended in the future
 };
 
-void buildTypeMap(DenseHashMap<AstExprFunction*, std::string>& functionTypes, DenseHashMap<AstLocal*, LuauBytecodeType>& localTypes, AstNode* root,
+void buildTypeMap(DenseHashMap<AstExprFunction*, std::string>& functionTypes, DenseHashMap<AstLocal*, LuauBytecodeType>& localTypes,
-    const char* vectorType)
+    DenseHashMap<AstExpr*, LuauBytecodeType>& exprTypes, AstNode* root, const char* vectorType, const BuiltinTypes& builtinTypes,
+    const DenseHashMap<AstExprCall*, int>& builtinCalls, const DenseHashMap<AstName, Compile::Global>& globals)
 {
-    TypeMapVisitor visitor(functionTypes, localTypes, vectorType);
+    TypeMapVisitor visitor(functionTypes, localTypes, exprTypes, vectorType, builtinTypes, builtinCalls, globals);
     root->visit(&visitor);
 }
 

Compiler/src/Types.h

@@ -4,13 +4,29 @@
 #include "Luau/Ast.h"
 #include "Luau/Bytecode.h"
 #include "Luau/DenseHash.h"
+#include "ValueTracking.h"
 
 #include <string>
 
 namespace Luau
 {
 
-void buildTypeMap(DenseHashMap<AstExprFunction*, std::string>& functionTypes, DenseHashMap<AstLocal*, LuauBytecodeType>& localTypes, AstNode* root,
+struct BuiltinTypes
-    const char* vectorType);
+{
+    BuiltinTypes(const char* vectorType)
+        : vectorType{{}, std::nullopt, AstName{vectorType}, std::nullopt, {}}
+    {
+    }
+
+    // AstName use here will not match the AstNameTable, but the was we use them here always force a full string compare
+    AstTypeReference booleanType{{}, std::nullopt, AstName{"boolean"}, std::nullopt, {}};
+    AstTypeReference numberType{{}, std::nullopt, AstName{"number"}, std::nullopt, {}};
+    AstTypeReference stringType{{}, std::nullopt, AstName{"string"}, std::nullopt, {}};
+    AstTypeReference vectorType;
+};
+
+void buildTypeMap(DenseHashMap<AstExprFunction*, std::string>& functionTypes, DenseHashMap<AstLocal*, LuauBytecodeType>& localTypes,
+    DenseHashMap<AstExpr*, LuauBytecodeType>& exprTypes, AstNode* root, const char* vectorType, const BuiltinTypes& builtinTypes,
+    const DenseHashMap<AstExprCall*, int>& builtinCalls, const DenseHashMap<AstName, Compile::Global>& globals);
 
 } // namespace Luau

VM/src/ldebug.cpp

@@ -12,6 +12,8 @@
 #include <string.h>
 #include <stdio.h>
 
+LUAU_FASTFLAGVARIABLE(LuauPushErrorStackCheck, false)
+
 static const char* getfuncname(Closure* f);
 
 static int currentpc(lua_State* L, CallInfo* ci)
@@ -330,12 +332,18 @@ l_noret luaG_runerrorL(lua_State* L, const char* fmt, ...)
     vsnprintf(result, sizeof(result), fmt, argp);
     va_end(argp);
 
+    if (FFlag::LuauPushErrorStackCheck)
+        lua_rawcheckstack(L, 1);
+
     pusherror(L, result);
     luaD_throw(L, LUA_ERRRUN);
 }
 
 void luaG_pusherror(lua_State* L, const char* error)
 {
+    if (FFlag::LuauPushErrorStackCheck)
+        lua_rawcheckstack(L, 1);
+
     pusherror(L, error);
 }
 

VM/src/lmem.cpp

@@ -53,6 +53,10 @@
  * for each block size there's a page free list that contains pages that have at least one free block
  * (global_State::freegcopages). This free list is used to make sure object allocation is O(1).
  *
+ * When LUAU_ASSERTENABLED is enabled, all non-GCO pages are also linked in a list (global_State::allpages).
+ * Because this list is not strictly required for runtime operations, it is only tracked for the purposes of
+ * debugging. While overhead of linking those pages together is very small, unnecessary operations are avoided.
+ *
  * Compared to GCOs, regular allocations have two important differences: they can be freed in isolation,
  * and they don't start with a GC header. Because of this, each allocation is prefixed with block metadata,
  * which contains the pointer to the page for allocated blocks, and the pointer to the next free block
@@ -190,6 +194,12 @@ const SizeClassConfig kSizeClassConfig;
 #define metadata(block) (*(void**)(block))
 #define freegcolink(block) (*(void**)((char*)block + kGCOLinkOffset))
 
+#if defined(LUAU_ASSERTENABLED)
+#define debugpageset(x) (x)
+#else
+#define debugpageset(x) NULL
+#endif
+
 struct lua_Page
 {
     // list of pages with free blocks
@@ -336,7 +346,7 @@ static void* newblock(lua_State* L, int sizeClass)
 
     // slow path: no page in the freelist, allocate a new one
     if (!page)
-        page = newclasspage(L, g->freepages, NULL, sizeClass, true);
+        page = newclasspage(L, g->freepages, debugpageset(&g->allpages), sizeClass, true);
 
     LUAU_ASSERT(!page->prev);
     LUAU_ASSERT(page->freeList || page->freeNext >= 0);
@@ -457,7 +467,7 @@ static void freeblock(lua_State* L, int sizeClass, void* block)
 
     // if it's the last block in the page, we don't need the page
     if (page->busyBlocks == 0)
-        freeclasspage(L, g->freepages, NULL, page, sizeClass);
+        freeclasspage(L, g->freepages, debugpageset(&g->allpages), page, sizeClass);
 }
 
 static void freegcoblock(lua_State* L, int sizeClass, void* block, lua_Page* page)

VM/src/lstate.cpp

@@ -204,6 +204,7 @@ lua_State* lua_newstate(lua_Alloc f, void* ud)
         g->freepages[i] = NULL;
         g->freegcopages[i] = NULL;
     }
+    g->allpages = NULL;
     g->allgcopages = NULL;
     g->sweepgcopage = NULL;
     for (i = 0; i < LUA_T_COUNT; i++)

VM/src/lstate.h

@@ -188,7 +188,8 @@ typedef struct global_State
 
     struct lua_Page* freepages[LUA_SIZECLASSES]; // free page linked list for each size class for non-collectable objects
     struct lua_Page* freegcopages[LUA_SIZECLASSES]; // free page linked list for each size class for collectable objects
-    struct lua_Page* allgcopages; // page linked list with all pages for all classes
+    struct lua_Page* allpages; // page linked list with all pages for all non-collectable object classes (available with LUAU_ASSERTENABLED)
+    struct lua_Page* allgcopages; // page linked list with all pages for all collectable object classes
     struct lua_Page* sweepgcopage; // position of the sweep in `allgcopages'
 
     size_t memcatbytes[LUA_MEMORY_CATEGORIES]; // total amount of memory used by each memory category

VM/src/ltablib.cpp

@@ -12,6 +12,7 @@
 #include "lvm.h"
 
 LUAU_DYNAMIC_FASTFLAGVARIABLE(LuauFastCrossTableMove, false)
+LUAU_DYNAMIC_FASTFLAGVARIABLE(LuauFastTableMaxn, false)
 LUAU_DYNAMIC_FASTFLAGVARIABLE(LuauFasterConcat, false)
 
 static int foreachi(lua_State* L)
@@ -55,17 +56,45 @@ static int maxn(lua_State* L)
 {
     double max = 0;
     luaL_checktype(L, 1, LUA_TTABLE);
-    lua_pushnil(L); // first key
+
-    while (lua_next(L, 1))
+    if (DFFlag::LuauFastTableMaxn)
     {
-        lua_pop(L, 1); // remove value
+        Table* t = hvalue(L->base);
-        if (lua_type(L, -1) == LUA_TNUMBER)
+
+        for (int i = 0; i < t->sizearray; i++)
         {
-            double v = lua_tonumber(L, -1);
+            if (!ttisnil(&t->array[i]))
-            if (v > max)
+                max = i + 1;
-                max = v;
+        }
+
+        for (int i = 0; i < sizenode(t); i++)
+        {
+            LuaNode* n = gnode(t, i);
+
+            if (!ttisnil(gval(n)) && ttisnumber(gkey(n)))
+            {
+                double v = nvalue(gkey(n));
+
+                if (v > max)
+                    max = v;
+            }
         }
     }
+    else
+    {
+        lua_pushnil(L); // first key
+        while (lua_next(L, 1))
+        {
+            lua_pop(L, 1); // remove value
+            if (lua_type(L, -1) == LUA_TNUMBER)
+            {
+                double v = lua_tonumber(L, -1);
+                if (v > max)
+                    max = v;
+            }
+        }
+    }
+
     lua_pushnumber(L, max);
     return 1;
 }

tests/IrLowering.test.cpp

@@ -18,8 +18,12 @@ LUAU_FASTFLAG(LuauCompileTypeInfo)
 LUAU_FASTFLAG(LuauLoadTypeInfo)
 LUAU_FASTFLAG(LuauCodegenTypeInfo)
 LUAU_FASTFLAG(LuauTypeInfoLookupImprovement)
+LUAU_FASTFLAG(LuauCodegenIrTypeNames)
+LUAU_FASTFLAG(LuauCompileTempTypeInfo)
+LUAU_FASTFLAG(LuauCodegenFixVectorFields)
+LUAU_FASTFLAG(LuauCodegenVectorMispredictFix)
 
-static std::string getCodegenAssembly(const char* source, bool includeIrTypes = false)
+static std::string getCodegenAssembly(const char* source, bool includeIrTypes = false, int debugLevel = 1)
 {
     Luau::CodeGen::AssemblyOptions options;
 
@@ -47,7 +51,7 @@ static std::string getCodegenAssembly(const char* source, bool includeIrTypes =
     Luau::CompileOptions copts = {};
 
     copts.optimizationLevel = 2;
-    copts.debugLevel = 1;
+    copts.debugLevel = debugLevel;
     copts.typeInfoLevel = 1;
     copts.vectorCtor = "vector";
     copts.vectorType = "vector";
@@ -66,6 +70,20 @@ static std::string getCodegenAssembly(const char* source, bool includeIrTypes =
     return "";
 }
 
+static std::string getCodegenHeader(const char* source)
+{
+    std::string assembly = getCodegenAssembly(source, /* includeIrTypes */ true, /* debugLevel */ 2);
+
+    auto bytecodeStart = assembly.find("bb_bytecode_0:");
+
+    if (bytecodeStart == std::string::npos)
+        bytecodeStart = assembly.find("bb_0:");
+
+    REQUIRE(bytecodeStart != std::string::npos);
+
+    return assembly.substr(0, bytecodeStart);
+}
+
 TEST_SUITE_BEGIN("IrLowering");
 
 TEST_CASE("VectorReciprocal")
@@ -451,6 +469,50 @@ bb_bytecode_1:
 )");
 }
 
+TEST_CASE("VectorRandomProp")
+{
+    ScopedFastFlag luauCodegenRemoveDeadStores{FFlag::LuauCodegenRemoveDeadStores5, true};
+    ScopedFastFlag luauCodegenFixVectorFields{FFlag::LuauCodegenFixVectorFields, true};
+    ScopedFastFlag luauCodegenVectorMispredictFix{FFlag::LuauCodegenVectorMispredictFix, true};
+
+    CHECK_EQ("\n" + getCodegenAssembly(R"(
+local function foo(a: vector)
+    return a.XX + a.YY + a.ZZ
+end
+)"),
+        R"(
+; function foo($arg0) line 2
+bb_0:
+  CHECK_TAG R0, tvector, exit(entry)
+  JUMP bb_2
+bb_2:
+  JUMP bb_bytecode_1
+bb_bytecode_1:
+  FALLBACK_GETTABLEKS 0u, R3, R0, K0
+  FALLBACK_GETTABLEKS 2u, R4, R0, K1
+  CHECK_TAG R3, tnumber, bb_fallback_3
+  CHECK_TAG R4, tnumber, bb_fallback_3
+  %14 = LOAD_DOUBLE R3
+  %16 = ADD_NUM %14, R4
+  STORE_DOUBLE R2, %16
+  STORE_TAG R2, tnumber
+  JUMP bb_4
+bb_4:
+  CHECK_TAG R0, tvector, exit(5)
+  FALLBACK_GETTABLEKS 5u, R3, R0, K2
+  CHECK_TAG R2, tnumber, bb_fallback_5
+  CHECK_TAG R3, tnumber, bb_fallback_5
+  %30 = LOAD_DOUBLE R2
+  %32 = ADD_NUM %30, R3
+  STORE_DOUBLE R1, %32
+  STORE_TAG R1, tnumber
+  JUMP bb_6
+bb_6:
+  INTERRUPT 8u
+  RETURN R1, 1i
+)");
+}
+
 TEST_CASE("UserDataGetIndex")
 {
     ScopedFastFlag luauCodegenDirectUserdataFlow{FFlag::LuauCodegenDirectUserdataFlow, true};
@@ -860,4 +922,422 @@ bb_bytecode_0:
 )");
 }
 
+TEST_CASE("ResolveTablePathTypes")
+{
+    ScopedFastFlag sffs[]{{FFlag::LuauLoadTypeInfo, true}, {FFlag::LuauCompileTypeInfo, true}, {FFlag::LuauCodegenTypeInfo, true},
+        {FFlag::LuauCodegenRemoveDeadStores5, true}, {FFlag::LuauTypeInfoLookupImprovement, true}, {FFlag::LuauCodegenIrTypeNames, true},
+        {FFlag::LuauCompileTempTypeInfo, true}};
+
+    CHECK_EQ("\n" + getCodegenAssembly(R"(
+type Vertex = {pos: vector, normal: vector}
+
+local function foo(arr: {Vertex}, i)
+    local v = arr[i]
+
+    return v.pos.Y
+end
+)",
+                        /* includeIrTypes */ true, /* debugLevel */ 2),
+        R"(
+; function foo(arr, i) line 4
+; R0: table [argument 'arr']
+; R2: table from 0 to 6 [local 'v']
+; R4: vector from 3 to 5
+bb_0:
+  CHECK_TAG R0, ttable, exit(entry)
+  JUMP bb_2
+bb_2:
+  JUMP bb_bytecode_1
+bb_bytecode_1:
+  CHECK_TAG R1, tnumber, bb_fallback_3
+  %8 = LOAD_POINTER R0
+  %9 = LOAD_DOUBLE R1
+  %10 = TRY_NUM_TO_INDEX %9, bb_fallback_3
+  %11 = SUB_INT %10, 1i
+  CHECK_ARRAY_SIZE %8, %11, bb_fallback_3
+  CHECK_NO_METATABLE %8, bb_fallback_3
+  %14 = GET_ARR_ADDR %8, %11
+  %15 = LOAD_TVALUE %14
+  STORE_TVALUE R2, %15
+  JUMP bb_4
+bb_4:
+  CHECK_TAG R2, ttable, exit(1)
+  %23 = LOAD_POINTER R2
+  %24 = GET_SLOT_NODE_ADDR %23, 1u, K0
+  CHECK_SLOT_MATCH %24, K0, bb_fallback_5
+  %26 = LOAD_TVALUE %24, 0i
+  STORE_TVALUE R4, %26
+  JUMP bb_6
+bb_6:
+  CHECK_TAG R4, tvector, exit(3)
+  %33 = LOAD_FLOAT R4, 4i
+  STORE_DOUBLE R3, %33
+  STORE_TAG R3, tnumber
+  INTERRUPT 5u
+  RETURN R3, 1i
+)");
+}
+
+TEST_CASE("ResolvableSimpleMath")
+{
+    ScopedFastFlag sffs[]{{FFlag::LuauLoadTypeInfo, true}, {FFlag::LuauCompileTypeInfo, true}, {FFlag::LuauCodegenTypeInfo, true},
+        {FFlag::LuauCodegenRemoveDeadStores5, true}, {FFlag::LuauTypeInfoLookupImprovement, true}, {FFlag::LuauCodegenIrTypeNames, true},
+        {FFlag::LuauCompileTempTypeInfo, true}};
+
+    CHECK_EQ("\n" + getCodegenHeader(R"(
+type Vertex = { p: vector, uv: vector, n: vector, t: vector, b: vector, h: number }
+local mesh: { vertices: {Vertex}, indices: {number} } = ...
+
+local function compute()
+    for i = 1,#mesh.indices,3 do
+        local a = mesh.vertices[mesh.indices[i]]
+        local b = mesh.vertices[mesh.indices[i + 1]]
+        local c = mesh.vertices[mesh.indices[i + 2]]
+
+        local vba = b.p - a.p
+        local vca = c.p - a.p
+
+        local uvba = b.uv - a.uv
+        local uvca = c.uv - a.uv
+
+        local r = 1.0 / (uvba.X * uvca.Y - uvca.X * uvba.Y);
+
+        local sdir = (uvca.Y * vba - uvba.Y * vca) * r
+
+        a.t += sdir
+    end
+end
+)"),
+        R"(
+; function compute() line 5
+; U0: table ['mesh']
+; R2: number from 0 to 78 [local 'i']
+; R3: table from 7 to 78 [local 'a']
+; R4: table from 15 to 78 [local 'b']
+; R5: table from 24 to 78 [local 'c']
+; R6: vector from 33 to 78 [local 'vba']
+; R7: vector from 37 to 38
+; R7: vector from 38 to 78 [local 'vca']
+; R8: vector from 37 to 38
+; R8: vector from 42 to 43
+; R8: vector from 43 to 78 [local 'uvba']
+; R9: vector from 42 to 43
+; R9: vector from 47 to 48
+; R9: vector from 48 to 78 [local 'uvca']
+; R10: vector from 47 to 48
+; R10: vector from 52 to 53
+; R10: number from 53 to 78 [local 'r']
+; R11: vector from 52 to 53
+; R11: vector from 65 to 78 [local 'sdir']
+; R12: vector from 72 to 73
+; R12: vector from 75 to 76
+; R13: vector from 71 to 72
+; R14: vector from 71 to 72
+)");
+}
+
+TEST_CASE("ResolveVectorNamecalls")
+{
+    ScopedFastFlag sffs[]{{FFlag::LuauLoadTypeInfo, true}, {FFlag::LuauCompileTypeInfo, true}, {FFlag::LuauCodegenTypeInfo, true},
+        {FFlag::LuauCodegenRemoveDeadStores5, true}, {FFlag::LuauTypeInfoLookupImprovement, true}, {FFlag::LuauCodegenIrTypeNames, true},
+        {FFlag::LuauCompileTempTypeInfo, true}, {FFlag::LuauCodegenDirectUserdataFlow, true}};
+
+    CHECK_EQ("\n" + getCodegenAssembly(R"(
+type Vertex = {pos: vector, normal: vector}
+
+local function foo(arr: {Vertex}, i)
+    return arr[i].normal:Dot(vector(0.707, 0, 0.707))
+end
+)",
+                        /* includeIrTypes */ true),
+        R"(
+; function foo($arg0, $arg1) line 4
+; R0: table [argument]
+; R2: vector from 4 to 6
+bb_0:
+  CHECK_TAG R0, ttable, exit(entry)
+  JUMP bb_2
+bb_2:
+  JUMP bb_bytecode_1
+bb_bytecode_1:
+  CHECK_TAG R1, tnumber, bb_fallback_3
+  %8 = LOAD_POINTER R0
+  %9 = LOAD_DOUBLE R1
+  %10 = TRY_NUM_TO_INDEX %9, bb_fallback_3
+  %11 = SUB_INT %10, 1i
+  CHECK_ARRAY_SIZE %8, %11, bb_fallback_3
+  CHECK_NO_METATABLE %8, bb_fallback_3
+  %14 = GET_ARR_ADDR %8, %11
+  %15 = LOAD_TVALUE %14
+  STORE_TVALUE R3, %15
+  JUMP bb_4
+bb_4:
+  CHECK_TAG R3, ttable, bb_fallback_5
+  %23 = LOAD_POINTER R3
+  %24 = GET_SLOT_NODE_ADDR %23, 1u, K0
+  CHECK_SLOT_MATCH %24, K0, bb_fallback_5
+  %26 = LOAD_TVALUE %24, 0i
+  STORE_TVALUE R2, %26
+  JUMP bb_6
+bb_6:
+  %31 = LOAD_TVALUE K1, 0i, tvector
+  STORE_TVALUE R4, %31
+  CHECK_TAG R2, tvector, exit(4)
+  FALLBACK_NAMECALL 4u, R2, R2, K2
+  INTERRUPT 6u
+  SET_SAVEDPC 7u
+  CALL R2, 2i, -1i
+  INTERRUPT 7u
+  RETURN R2, -1i
+)");
+}
+
+TEST_CASE("ImmediateTypeAnnotationHelp")
+{
+    ScopedFastFlag sffs[]{{FFlag::LuauLoadTypeInfo, true}, {FFlag::LuauCompileTypeInfo, true}, {FFlag::LuauCodegenTypeInfo, true},
+        {FFlag::LuauCodegenRemoveDeadStores5, true}, {FFlag::LuauTypeInfoLookupImprovement, true}, {FFlag::LuauCodegenIrTypeNames, true},
+        {FFlag::LuauCompileTempTypeInfo, true}};
+
+    CHECK_EQ("\n" + getCodegenAssembly(R"(
+local function foo(arr, i)
+    return (arr[i] :: vector) / 5
+end
+)",
+                        /* includeIrTypes */ true),
+        R"(
+; function foo($arg0, $arg1) line 2
+; R3: vector from 1 to 2
+bb_bytecode_0:
+  CHECK_TAG R0, ttable, bb_fallback_1
+  CHECK_TAG R1, tnumber, bb_fallback_1
+  %4 = LOAD_POINTER R0
+  %5 = LOAD_DOUBLE R1
+  %6 = TRY_NUM_TO_INDEX %5, bb_fallback_1
+  %7 = SUB_INT %6, 1i
+  CHECK_ARRAY_SIZE %4, %7, bb_fallback_1
+  CHECK_NO_METATABLE %4, bb_fallback_1
+  %10 = GET_ARR_ADDR %4, %7
+  %11 = LOAD_TVALUE %10
+  STORE_TVALUE R3, %11
+  JUMP bb_2
+bb_2:
+  CHECK_TAG R3, tvector, exit(1)
+  %19 = LOAD_TVALUE R3
+  %20 = NUM_TO_VEC 5
+  %21 = DIV_VEC %19, %20
+  %22 = TAG_VECTOR %21
+  STORE_TVALUE R2, %22
+  INTERRUPT 2u
+  RETURN R2, 1i
+)");
+}
+
+TEST_CASE("UnaryTypeResolve")
+{
+    ScopedFastFlag sffs[]{{FFlag::LuauLoadTypeInfo, true}, {FFlag::LuauCompileTypeInfo, true}, {FFlag::LuauCodegenTypeInfo, true},
+        {FFlag::LuauCodegenRemoveDeadStores5, true}, {FFlag::LuauTypeInfoLookupImprovement, true}, {FFlag::LuauCodegenIrTypeNames, true},
+        {FFlag::LuauCompileTempTypeInfo, true}};
+
+    CHECK_EQ("\n" + getCodegenHeader(R"(
+local function foo(a, b: vector, c)
+    local d = not a
+    local e = -b
+    local f = #c
+    return (if d then e else vector(f, 2, 3)).X
+end
+)"),
+        R"(
+; function foo(a, b, c) line 2
+; R1: vector [argument 'b']
+; R3: boolean from 0 to 16 [local 'd']
+; R4: vector from 1 to 16 [local 'e']
+; R5: number from 2 to 16 [local 'f']
+; R7: vector from 13 to 15
+)");
+}
+
+TEST_CASE("ForInManualAnnotation")
+{
+    ScopedFastFlag sffs[]{{FFlag::LuauLoadTypeInfo, true}, {FFlag::LuauCompileTypeInfo, true}, {FFlag::LuauCodegenTypeInfo, true},
+        {FFlag::LuauCodegenRemoveDeadStores5, true}, {FFlag::LuauTypeInfoLookupImprovement, true}, {FFlag::LuauCodegenIrTypeNames, true},
+        {FFlag::LuauCompileTempTypeInfo, true}};
+
+    CHECK_EQ("\n" + getCodegenAssembly(R"(
+type Vertex = {pos: vector, normal: vector}
+
+local function foo(a: {Vertex})
+    local sum = 0
+    for k, v: Vertex in ipairs(a) do
+        sum += v.pos.X
+    end
+    return sum
+end
+)",
+                        /* includeIrTypes */ true, /* debugLevel */ 2),
+        R"(
+; function foo(a) line 4
+; R0: table [argument 'a']
+; R1: number from 0 to 14 [local 'sum']
+; R5: number from 5 to 11 [local 'k']
+; R6: table from 5 to 11 [local 'v']
+; R8: vector from 8 to 10
+bb_0:
+  CHECK_TAG R0, ttable, exit(entry)
+  JUMP bb_4
+bb_4:
+  JUMP bb_bytecode_1
+bb_bytecode_1:
+  STORE_DOUBLE R1, 0
+  STORE_TAG R1, tnumber
+  CHECK_SAFE_ENV exit(1)
+  JUMP_EQ_TAG K1, tnil, bb_fallback_6, bb_5
+bb_5:
+  %9 = LOAD_TVALUE K1
+  STORE_TVALUE R2, %9
+  JUMP bb_7
+bb_7:
+  %15 = LOAD_TVALUE R0
+  STORE_TVALUE R3, %15
+  INTERRUPT 4u
+  SET_SAVEDPC 5u
+  CALL R2, 1i, 3i
+  CHECK_SAFE_ENV exit(5)
+  CHECK_TAG R3, ttable, bb_fallback_8
+  CHECK_TAG R4, tnumber, bb_fallback_8
+  JUMP_CMP_NUM R4, 0, not_eq, bb_fallback_8, bb_9
+bb_9:
+  STORE_TAG R2, tnil
+  STORE_POINTER R4, 0i
+  STORE_EXTRA R4, 128i
+  STORE_TAG R4, tlightuserdata
+  JUMP bb_bytecode_3
+bb_bytecode_2:
+  CHECK_TAG R6, ttable, exit(6)
+  %35 = LOAD_POINTER R6
+  %36 = GET_SLOT_NODE_ADDR %35, 6u, K2
+  CHECK_SLOT_MATCH %36, K2, bb_fallback_10
+  %38 = LOAD_TVALUE %36, 0i
+  STORE_TVALUE R8, %38
+  JUMP bb_11
+bb_11:
+  CHECK_TAG R8, tvector, exit(8)
+  %45 = LOAD_FLOAT R8, 0i
+  STORE_DOUBLE R7, %45
+  STORE_TAG R7, tnumber
+  CHECK_TAG R1, tnumber, exit(10)
+  %52 = LOAD_DOUBLE R1
+  %54 = ADD_NUM %52, %45
+  STORE_DOUBLE R1, %54
+  JUMP bb_bytecode_3
+bb_bytecode_3:
+  INTERRUPT 11u
+  CHECK_TAG R2, tnil, bb_fallback_13
+  %60 = LOAD_POINTER R3
+  %61 = LOAD_INT R4
+  %62 = GET_ARR_ADDR %60, %61
+  CHECK_ARRAY_SIZE %60, %61, bb_12
+  %64 = LOAD_TAG %62
+  JUMP_EQ_TAG %64, tnil, bb_12, bb_14
+bb_14:
+  %66 = ADD_INT %61, 1i
+  STORE_INT R4, %66
+  %68 = INT_TO_NUM %66
+  STORE_DOUBLE R5, %68
+  STORE_TAG R5, tnumber
+  %71 = LOAD_TVALUE %62
+  STORE_TVALUE R6, %71
+  JUMP bb_bytecode_2
+bb_12:
+  INTERRUPT 13u
+  RETURN R1, 1i
+)");
+}
+
+TEST_CASE("ForInAutoAnnotationIpairs")
+{
+    ScopedFastFlag sffs[]{{FFlag::LuauLoadTypeInfo, true}, {FFlag::LuauCompileTypeInfo, true}, {FFlag::LuauCodegenTypeInfo, true},
+        {FFlag::LuauCodegenRemoveDeadStores5, true}, {FFlag::LuauTypeInfoLookupImprovement, true}, {FFlag::LuauCodegenIrTypeNames, true},
+        {FFlag::LuauCompileTempTypeInfo, true}};
+
+    CHECK_EQ("\n" + getCodegenHeader(R"(
+type Vertex = {pos: vector, normal: vector}
+
+local function foo(a: {Vertex})
+    local sum = 0
+    for k, v in ipairs(a) do
+        local n = v.pos.X
+        sum += n
+    end
+    return sum
+end
+)"),
+        R"(
+; function foo(a) line 4
+; R0: table [argument 'a']
+; R1: number from 0 to 14 [local 'sum']
+; R5: number from 5 to 11 [local 'k']
+; R6: table from 5 to 11 [local 'v']
+; R7: number from 6 to 11 [local 'n']
+; R8: vector from 8 to 10
+)");
+}
+
+TEST_CASE("ForInAutoAnnotationPairs")
+{
+    ScopedFastFlag sffs[]{{FFlag::LuauLoadTypeInfo, true}, {FFlag::LuauCompileTypeInfo, true}, {FFlag::LuauCodegenTypeInfo, true},
+        {FFlag::LuauCodegenRemoveDeadStores5, true}, {FFlag::LuauTypeInfoLookupImprovement, true}, {FFlag::LuauCodegenIrTypeNames, true},
+        {FFlag::LuauCompileTempTypeInfo, true}};
+
+    CHECK_EQ("\n" + getCodegenHeader(R"(
+type Vertex = {pos: vector, normal: vector}
+
+local function foo(a: {[string]: Vertex})
+    local sum = 0
+    for k, v in pairs(a) do
+        local n = v.pos.X
+        sum += n
+    end
+    return sum
+end
+)"),
+        R"(
+; function foo(a) line 4
+; R0: table [argument 'a']
+; R1: number from 0 to 14 [local 'sum']
+; R5: string from 5 to 11 [local 'k']
+; R6: table from 5 to 11 [local 'v']
+; R7: number from 6 to 11 [local 'n']
+; R8: vector from 8 to 10
+)");
+}
+
+TEST_CASE("ForInAutoAnnotationGeneric")
+{
+    ScopedFastFlag sffs[]{{FFlag::LuauLoadTypeInfo, true}, {FFlag::LuauCompileTypeInfo, true}, {FFlag::LuauCodegenTypeInfo, true},
+        {FFlag::LuauCodegenRemoveDeadStores5, true}, {FFlag::LuauTypeInfoLookupImprovement, true}, {FFlag::LuauCodegenIrTypeNames, true},
+        {FFlag::LuauCompileTempTypeInfo, true}};
+
+    CHECK_EQ("\n" + getCodegenHeader(R"(
+type Vertex = {pos: vector, normal: vector}
+
+local function foo(a: {Vertex})
+    local sum = 0
+    for k, v in a do
+        local n = v.pos.X
+        sum += n
+    end
+    return sum
+end
+)"),
+        R"(
+; function foo(a) line 4
+; R0: table [argument 'a']
+; R1: number from 0 to 13 [local 'sum']
+; R5: number from 4 to 10 [local 'k']
+; R6: table from 4 to 10 [local 'v']
+; R7: number from 5 to 10 [local 'n']
+; R8: vector from 7 to 9
+)");
+}
+
 TEST_SUITE_END();

tests/Normalize.test.cpp

@@ -14,7 +14,7 @@ LUAU_FASTFLAG(DebugLuauDeferredConstraintResolution)
 LUAU_FASTFLAG(LuauFixNormalizeCaching)
 LUAU_FASTFLAG(LuauNormalizeNotUnknownIntersection)
 LUAU_FASTFLAG(LuauFixCyclicUnionsOfIntersections);
-
+LUAU_FASTINT(LuauTypeInferRecursionLimit)
 using namespace Luau;
 
 namespace
@@ -962,4 +962,32 @@ TEST_CASE_FIXTURE(NormalizeFixture, "intersect_with_not_unknown")
     CHECK("never" == toString(normalizer.typeFromNormal(*normalized.get())));
 }
 
+TEST_CASE_FIXTURE(NormalizeFixture, "cyclic_stack_overflow_1")
+{
+    ScopedFastInt sfi{FInt::LuauTypeInferRecursionLimit, 165};
+    this->unifierState.counters.recursionLimit = FInt::LuauTypeInferRecursionLimit;
+    TypeId t1 = arena.addType(TableType{});
+    TypeId t2 = arena.addType(TableType{});
+    TypeId t3 = arena.addType(IntersectionType{{t1, t2}});
+    asMutable(t1)->ty.get_if<TableType>()->props = {{"foo", Property::readonly(t2)}};
+    asMutable(t2)->ty.get_if<TableType>()->props = {{"foo", Property::readonly(t1)}};
+
+    std::shared_ptr<const NormalizedType> normalized = normalizer.normalize(t3);
+    CHECK(normalized);
+}
+
+TEST_CASE_FIXTURE(NormalizeFixture, "cyclic_stack_overflow_2")
+{
+    ScopedFastInt sfi{FInt::LuauTypeInferRecursionLimit, 165};
+    this->unifierState.counters.recursionLimit = FInt::LuauTypeInferRecursionLimit;
+    TypeId t1 = arena.addType(TableType{});
+    TypeId t2 = arena.addType(TableType{});
+    TypeId t3 = arena.addType(IntersectionType{{t1, t2}});
+    asMutable(t1)->ty.get_if<TableType>()->props = {{"foo", Property::readonly(t3)}};
+    asMutable(t2)->ty.get_if<TableType>()->props = {{"foo", Property::readonly(t1)}};
+
+    std::shared_ptr<const NormalizedType> normalized = normalizer.normalize(t3);
+    CHECK(normalized);
+}
+
 TEST_SUITE_END();

tests/TypeInfer.classes.test.cpp

@@ -17,6 +17,39 @@ LUAU_FASTFLAG(LuauAlwaysCommitInferencesOfFunctionCalls);
 
 TEST_SUITE_BEGIN("TypeInferClasses");
 
+TEST_CASE_FIXTURE(ClassFixture, "Luau.Analyze.CLI_crashes_on_this_test")
+{
+    CheckResult result = check(R"(
+        local CircularQueue = {}
+CircularQueue.__index = CircularQueue
+
+function CircularQueue:new()
+	local newCircularQueue = {
+		head = nil,
+	}
+	setmetatable(newCircularQueue, CircularQueue)
+
+	return newCircularQueue
+end
+
+function CircularQueue:push()
+	local newListNode
+
+	if self.head then
+		newListNode = {
+			prevNode = self.head.prevNode,
+			nextNode = self.head,
+		}
+		newListNode.prevNode.nextNode = newListNode
+		newListNode.nextNode.prevNode = newListNode
+	end
+end
+
+return CircularQueue
+
+    )");
+}
+
 TEST_CASE_FIXTURE(ClassFixture, "call_method_of_a_class")
 {
     CheckResult result = check(R"(

tests/TypeInfer.tables.test.cpp

@@ -4423,4 +4423,20 @@ TEST_CASE_FIXTURE(Fixture, "setindexer_multiple_tables_intersection")
     CHECK("({ [string]: number } & { [thread]: boolean }, boolean | number) -> ()" == toString(requireType("f")));
 }
 
+TEST_CASE_FIXTURE(Fixture, "insert_a_and_f_of_a_into_table_res_in_a_loop")
+{
+    CheckResult result = check(R"(
+        local function f(t)
+            local res = {}
+
+            for k, a in t do
+                res[k] = f(a)
+                res[k] = a
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+}
+
 TEST_SUITE_END();

tests/TypeInfer.test.cpp

@@ -782,7 +782,10 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "no_heap_use_after_free_error")
         end
     )");
 
-    LUAU_REQUIRE_ERRORS(result);
+    if (FFlag::DebugLuauDeferredConstraintResolution)
+        LUAU_REQUIRE_NO_ERRORS(result);
+    else
+        LUAU_REQUIRE_ERRORS(result);
 }
 
 TEST_CASE_FIXTURE(Fixture, "infer_type_assertion_value_type")
@@ -1540,19 +1543,33 @@ TEST_CASE_FIXTURE(Fixture, "typeof_cannot_refine_builtin_alias")
     )");
 }
 
-/*
+TEST_CASE_FIXTURE(BuiltinsFixture, "bad_iter_metamethod")
- * We had an issue where we tripped the canMutate() check when binding one
- * blocked type to another.
- */
-TEST_CASE_FIXTURE(Fixture, "delay_setIndexer_constraint_if_the_indexers_type_is_blocked")
 {
-    (void) check(R"(
+    CheckResult result = check(R"(
-        local SG = GetService(true)
+        function iter(): unknown
-        local lines: { [string]: typeof(SG.ScreenGui) } = {}
+            return nil
-        lines[deadline] = nil -- This line
+        end
+
+        local a = {__iter = iter}
+        setmetatable(a, a)
+
+        for i in a do
+        end
     )");
 
-    // As long as type inference doesn't trip an assert or crash, we're good!
+    if (FFlag::DebugLuauDeferredConstraintResolution)
+    {
+        LUAU_REQUIRE_ERROR_COUNT(1, result);
+
+        CannotCallNonFunction* ccnf = get<CannotCallNonFunction>(result.errors[0]);
+        REQUIRE(ccnf);
+
+        CHECK("unknown" == toString(ccnf->ty));
+    }
+    else
+    {
+        LUAU_REQUIRE_NO_ERRORS(result);
+    }
 }
 
 TEST_SUITE_END();

tests/TypeInfer.typestates.test.cpp

@@ -490,5 +490,34 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "typestates_do_not_apply_to_the_initial_local
     CHECK("number" == toString(requireTypeAtPosition({5, 14}), {true}));
 }
 
+TEST_CASE_FIXTURE(Fixture, "typestate_globals")
+{
+    ScopedFastFlag sff{FFlag::DebugLuauDeferredConstraintResolution, true};
+
+    loadDefinition(R"(
+        declare foo: string | number
+        declare function f(x: string): ()
+    )");
+
+    CheckResult result = check(R"(
+        foo = "a"
+        f(foo)
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+}
+
+TEST_CASE_FIXTURE(Fixture, "typestate_unknown_global")
+{
+    ScopedFastFlag sff{FFlag::DebugLuauDeferredConstraintResolution, true};
+
+    CheckResult result = check(R"(
+        x = 5
+    )");
+
+    LUAU_REQUIRE_ERROR_COUNT(1, result);
+
+    CHECK(get<UnknownSymbol>(result.errors[0]));
+}
 
 TEST_SUITE_END();

tests/conformance/tables.lua

@@ -306,10 +306,14 @@ end
 
 
 assert(table.maxn{} == 0)
+assert(table.maxn{[-100] = 1} == 0)
 assert(table.maxn{["1000"] = true} == 0)
 assert(table.maxn{["1000"] = true, [24.5] = 3} == 24.5)
 assert(table.maxn{[1000] = true} == 1000)
 assert(table.maxn{[10] = true, [100*math.pi] = print} == 100*math.pi)
+a = {[10] = 1, [20] = 2}
+a[20] = nil
+assert(table.maxn(a) == 10)
 
 
 -- int overflow

tools/faillist.txt

@@ -37,7 +37,6 @@ Differ.metatable_metamissing_left
 Differ.metatable_metamissing_right
 Differ.metatable_metanormal
 Differ.negation
-FrontendTest.accumulate_cached_errors_in_consistent_order
 FrontendTest.environments
 FrontendTest.imported_table_modification_2
 FrontendTest.it_should_be_safe_to_stringify_errors_when_full_type_graph_is_discarded
@@ -182,6 +181,7 @@ TableTests.infer_array
 TableTests.infer_indexer_from_array_like_table
 TableTests.infer_indexer_from_its_variable_type_and_unifiable
 TableTests.inferred_return_type_of_free_table
+TableTests.insert_a_and_f_of_a_into_table_res_in_a_loop
 TableTests.invariant_table_properties_means_instantiating_tables_in_assignment_is_unsound
 TableTests.invariant_table_properties_means_instantiating_tables_in_call_is_unsound
 TableTests.length_operator_union
@@ -269,7 +269,6 @@ TypeInfer.dont_report_type_errors_within_an_AstExprError
 TypeInfer.dont_report_type_errors_within_an_AstStatError
 TypeInfer.globals
 TypeInfer.globals2
-TypeInfer.globals_are_banned_in_strict_mode
 TypeInfer.infer_through_group_expr
 TypeInfer.no_stack_overflow_from_isoptional
 TypeInfer.recursive_function_that_invokes_itself_with_a_refinement_of_its_parameter
@@ -366,7 +365,6 @@ TypeInferLoops.properly_infer_iteratee_is_a_free_table
 TypeInferLoops.repeat_loop
 TypeInferLoops.varlist_declared_by_for_in_loop_should_be_free
 TypeInferLoops.while_loop
-TypeInferModules.custom_require_global
 TypeInferModules.do_not_modify_imported_types_5
 TypeInferModules.require
 TypeInferOOP.dont_suggest_using_colon_rather_than_dot_if_it_wont_help_2

tools/stackdbg.py

@@ -0,0 +1,94 @@
+#!usr/bin/python3
+"""
+To use this command, simply run the command:
+`command script import /path/to/your/game-engine/Client/Luau/tools/stackdbg.py`
+in the `lldb` interpreter. You can also add it to your .lldbinit file to have it be
+automatically imported.
+
+If using vscode, you can add the above command to your launch.json under `preRunCommands` for the appropriate target. For example:
+{
+    "name": "Luau.UnitTest",
+    "type": "lldb",
+    "request": "launch",
+    "program": "${workspaceFolder}/build/ninja/common-tests/noopt/Luau/Luau.UnitTest",
+    "preRunCommands": [
+        "command script import ${workspaceFolder}/Client/Luau/tools/stackdbg.py"
+    ],
+}
+
+Once this is loaded,
+`(lldb) help stack`
+or
+`(lldb) stack -h
+or
+`(lldb) stack --help
+
+can get you started
+"""
+
+import lldb
+import functools
+import argparse
+import shlex
+
+# Dumps the collected frame data
+def dump(collected):
+    for (frame_name, size_in_kb, live_size_kb, variables) in collected:
+        print(f'{frame_name}, locals: {size_in_kb}kb, fp-sp:  {live_size_kb}kb')
+        for (var_name, var_size, variable_obj) in variables:
+            print(f'    {var_name}, {var_size} bytes')
+
+def dbg_stack_pressure(frame, frames_to_show = 5, sort_frames = False, vars_to_show = 5, sort_vars = True):
+    totalKb = 0
+    collect = []
+    for f in frame.thread:
+        frame_name = f.GetFunctionName()
+        variables = [ (v.GetName(), v.GetByteSize(), v) for v in f.get_locals() ]
+        if sort_vars:
+            variables.sort(key = lambda x: x[1], reverse = True)
+        size_in_kb = functools.reduce(lambda x,y : x + y[1], variables, 0) / 1024
+
+        fp = f.GetFP()
+        sp = f.GetSP()
+        live_size_kb = round((fp - sp) / 1024, 2)
+
+        size_in_kb = round(size_in_kb, 2)
+        totalKb += size_in_kb
+        collect.append((frame_name, size_in_kb, live_size_kb, variables[:vars_to_show]))
+    if sort_frames:
+        collect.sort(key = lambda x: x[1], reverse = True)
+
+    print("******************** Report Stack Usage ********************")
+    totalMb = round(totalKb / 1024, 2)
+    print(f'{len(frame.thread)} stack frames used {totalMb}MB')
+    dump(collect[:frames_to_show])
+
+def stack(debugger, command, result, internal_dict):
+    """
+    usage: [-h] [-f FRAMES] [-fd] [-v VARS] [-vd]
+
+    optional arguments:
+    -h, --help            show this help message and exit
+    -f FRAMES, --frames FRAMES
+                        How many stack frames to display
+    -fd, --sort_frames    Sort frames
+    -v VARS, --vars VARS  How many variables per frame to display
+    -vd, --sort_vars      Sort frames
+    """
+
+    frame = debugger.GetSelectedTarget().GetProcess().GetSelectedThread().GetSelectedFrame()
+    args = shlex.split(command)
+    argparser = argparse.ArgumentParser(allow_abbrev = True)
+    argparser.add_argument("-f", "--frames", required=False, help="How many stack frames to display", default=5, type=int)
+    argparser.add_argument("-fd", "--sort_frames", required=False, help="Sort frames in descending order of stack usage", action="store_true", default=False)
+    argparser.add_argument("-v", "--vars", required=False, help="How many variables per frame to display", default=5, type=int)
+    argparser.add_argument("-vd", "--sort_vars", required=False, help="Sort locals in descending order of stack usage ", action="store_true", default=False)
+
+    args = argparser.parse_args(args)
+    dbg_stack_pressure(frame, frames_to_show=args.frames, sort_frames=args.sort_frames, vars_to_show=args.vars, sort_vars=args.sort_vars)
+
+# Initialization code to add commands
+def __lldb_init_module(debugger, internal_dict):
+    debugger.HandleCommand('command script add -f stackdbg.stack stack')
+    print("The 'stack' python command has been installed and is ready for use.")
+