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193 lines
7.8 KiB
C++
193 lines
7.8 KiB
C++
// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
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#pragma once
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#include "Luau/Error.h"
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#include "Luau/Location.h"
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#include "Luau/ParseOptions.h"
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#include "Luau/Scope.h"
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#include "Luau/Substitution.h"
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#include "Luau/TxnLog.h"
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#include "Luau/TypeArena.h"
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#include "Luau/UnifierSharedState.h"
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#include "Normalize.h"
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#include <unordered_set>
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namespace Luau
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{
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enum Variance
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{
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Covariant,
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Invariant
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};
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// A substitution which replaces singleton types by their wider types
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struct Widen : Substitution
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{
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Widen(TypeArena* arena, NotNull<BuiltinTypes> builtinTypes)
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: Substitution(TxnLog::empty(), arena)
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, builtinTypes(builtinTypes)
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{
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}
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NotNull<BuiltinTypes> builtinTypes;
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bool isDirty(TypeId ty) override;
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bool isDirty(TypePackId ty) override;
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TypeId clean(TypeId ty) override;
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TypePackId clean(TypePackId ty) override;
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bool ignoreChildren(TypeId ty) override;
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TypeId operator()(TypeId ty);
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TypePackId operator()(TypePackId ty);
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};
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/**
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* Normally, when we unify table properties, we must do so invariantly, but we
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* can introduce a special exception: If the table property in the subtype
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* position arises from a literal expression, it is safe to instead perform a
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* covariant check.
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*
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* This is very useful for typechecking cases where table literals (and trees of
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* table literals) are passed directly to functions.
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*
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* In this case, we know that the property has no other name referring to it and
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* so it is perfectly safe for the function to mutate the table any way it
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* wishes.
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*/
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using LiteralProperties = DenseHashSet<Name>;
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// TODO: Use this more widely.
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struct UnifierOptions
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{
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bool isFunctionCall = false;
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};
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struct Unifier
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{
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TypeArena* const types;
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NotNull<BuiltinTypes> builtinTypes;
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NotNull<Normalizer> normalizer;
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NotNull<Scope> scope; // const Scope maybe
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TxnLog log;
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bool failure = false;
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ErrorVec errors;
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Location location;
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Variance variance = Covariant;
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bool normalize = true; // Normalize unions and intersections if necessary
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bool checkInhabited = true; // Normalize types to check if they are inhabited
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CountMismatch::Context ctx = CountMismatch::Arg;
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// If true, generics act as free types when unifying.
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bool hideousFixMeGenericsAreActuallyFree = false;
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UnifierSharedState& sharedState;
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// When the Unifier is forced to unify two blocked types (or packs), they
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// get added to these vectors. The ConstraintSolver can use this to know
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// when it is safe to reattempt dispatching a constraint.
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std::vector<TypeId> blockedTypes;
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std::vector<TypePackId> blockedTypePacks;
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Unifier(NotNull<Normalizer> normalizer, NotNull<Scope> scope, const Location& location, Variance variance, TxnLog* parentLog = nullptr);
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// Configure the Unifier to test for scope subsumption via embedded Scope
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// pointers rather than TypeLevels.
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void enableNewSolver();
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// Test whether the two type vars unify. Never commits the result.
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ErrorVec canUnify(TypeId subTy, TypeId superTy);
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ErrorVec canUnify(TypePackId subTy, TypePackId superTy, bool isFunctionCall = false);
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/** Attempt to unify.
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* Populate the vector errors with any type errors that may arise.
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* Populate the transaction log with the set of TypeIds that need to be reset to undo the unification attempt.
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*/
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void tryUnify(
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TypeId subTy, TypeId superTy, bool isFunctionCall = false, bool isIntersection = false, const LiteralProperties* aliasableMap = nullptr);
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private:
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void tryUnify_(
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TypeId subTy, TypeId superTy, bool isFunctionCall = false, bool isIntersection = false, const LiteralProperties* aliasableMap = nullptr);
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void tryUnifyUnionWithType(TypeId subTy, const UnionType* uv, TypeId superTy);
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// Traverse the two types provided and block on any BlockedTypes we find.
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// Returns true if any types were blocked on.
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bool DEPRECATED_blockOnBlockedTypes(TypeId subTy, TypeId superTy);
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void tryUnifyTypeWithUnion(TypeId subTy, TypeId superTy, const UnionType* uv, bool cacheEnabled, bool isFunctionCall);
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void tryUnifyTypeWithIntersection(TypeId subTy, TypeId superTy, const IntersectionType* uv);
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void tryUnifyIntersectionWithType(TypeId subTy, const IntersectionType* uv, TypeId superTy, bool cacheEnabled, bool isFunctionCall);
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void tryUnifyNormalizedTypes(TypeId subTy, TypeId superTy, const NormalizedType& subNorm, const NormalizedType& superNorm, std::string reason,
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std::optional<TypeError> error = std::nullopt);
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void tryUnifyPrimitives(TypeId subTy, TypeId superTy);
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void tryUnifySingletons(TypeId subTy, TypeId superTy);
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void tryUnifyFunctions(TypeId subTy, TypeId superTy, bool isFunctionCall = false);
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void tryUnifyTables(TypeId subTy, TypeId superTy, bool isIntersection = false, const LiteralProperties* aliasableMap = nullptr);
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void tryUnifyScalarShape(TypeId subTy, TypeId superTy, bool reversed);
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void tryUnifyWithMetatable(TypeId subTy, TypeId superTy, bool reversed);
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void tryUnifyWithClass(TypeId subTy, TypeId superTy, bool reversed);
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void tryUnifyNegations(TypeId subTy, TypeId superTy);
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TypePackId tryApplyOverloadedFunction(TypeId function, const NormalizedFunctionType& overloads, TypePackId args);
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TypeId widen(TypeId ty);
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TypePackId widen(TypePackId tp);
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TypeId deeplyOptional(TypeId ty, std::unordered_map<TypeId, TypeId> seen = {});
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bool canCacheResult(TypeId subTy, TypeId superTy);
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void cacheResult(TypeId subTy, TypeId superTy, size_t prevErrorCount);
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public:
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void tryUnify(TypePackId subTy, TypePackId superTy, bool isFunctionCall = false);
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private:
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void tryUnify_(TypePackId subTy, TypePackId superTy, bool isFunctionCall = false);
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void tryUnifyVariadics(TypePackId subTy, TypePackId superTy, bool reversed, int subOffset = 0);
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void tryUnifyWithAny(TypeId subTy, TypeId anyTy);
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void tryUnifyWithAny(TypePackId subTy, TypePackId anyTp);
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std::optional<TypeId> findTablePropertyRespectingMeta(TypeId lhsType, Name name);
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TxnLog combineLogsIntoIntersection(std::vector<TxnLog> logs);
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TxnLog combineLogsIntoUnion(std::vector<TxnLog> logs);
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public:
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// Returns true if the type "needle" already occurs within "haystack" and reports an "infinite type error"
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bool occursCheck(TypeId needle, TypeId haystack, bool reversed);
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bool occursCheck(DenseHashSet<TypeId>& seen, TypeId needle, TypeId haystack);
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bool occursCheck(TypePackId needle, TypePackId haystack, bool reversed);
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bool occursCheck(DenseHashSet<TypePackId>& seen, TypePackId needle, TypePackId haystack);
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Unifier makeChildUnifier();
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void reportError(TypeError err);
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LUAU_NOINLINE void reportError(Location location, TypeErrorData data);
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private:
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TypeMismatch::Context mismatchContext();
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void checkChildUnifierTypeMismatch(const ErrorVec& innerErrors, TypeId wantedType, TypeId givenType);
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void checkChildUnifierTypeMismatch(const ErrorVec& innerErrors, const std::string& prop, TypeId wantedType, TypeId givenType);
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[[noreturn]] void ice(const std::string& message, const Location& location);
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[[noreturn]] void ice(const std::string& message);
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// Available after regular type pack unification errors
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std::optional<int> firstPackErrorPos;
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// If true, we do a bunch of small things differently to work better with
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// the new type inference engine. Most notably, we use the Scope hierarchy
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// directly rather than using TypeLevels.
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bool useNewSolver = false;
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};
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void promoteTypeLevels(TxnLog& log, const TypeArena* arena, TypeLevel minLevel, Scope* outerScope, bool useScope, TypePackId tp);
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std::optional<TypeError> hasUnificationTooComplex(const ErrorVec& errors);
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std::optional<TypeError> hasCountMismatch(const ErrorVec& errors);
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} // namespace Luau
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