Sync to upstream/release/619 (#1218)

# What's Changed ## New Type Solver - Many fixes to crashes, assertions, and hangs - Binary type family aliases now have a default parameter - Added a debug check for unsolved types escaping the constraint solver - Overloaded functions are no longer inferred - Unification creates additional subtyping constraints for blocked types - Attempt to guess the result type for type families that are too large to resolve timely ## Native Code Generation - Fixed `IrCmd::CHECK_TRUTHY` lowering in a specific case - Detailed compilation errors are now supported - More work on the new allocator --- # Internal Contributors Co-authored-by: Aaron Weiss <aaronweiss@roblox.com> Co-authored-by: Alexander McCord <amccord@roblox.com> Co-authored-by: Andy Friesen <afriesen@roblox.com> Co-authored-by: James McNellis <jmcnellis@roblox.com> Co-authored-by: Lily Brown <lbrown@roblox.com> Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com> Co-authored-by: Vighnesh Vijay <vvijay@roblox.com>
luau-lang · Mar 30, 2024 · 47ad768 · 47ad768
1 parent bac8511
commit 47ad768
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Showing 59 changed files with 1,846 additions and 619 deletions.
diff --git a/Analysis/include/Luau/Constraint.h b/Analysis/include/Luau/Constraint.h
@@ -224,7 +224,6 @@ struct HasIndexerConstraint
 // If the table is a free or unsealed table, we augment it with a new indexer.
 struct SetIndexerConstraint
 {
-    TypeId resultType;
     TypeId subjectType;
     TypeId indexType;
     TypeId propType;
@@ -256,6 +255,20 @@ struct UnpackConstraint
     bool resultIsLValue = false;
 };
 
+// resultType ~ unpack sourceType
+//
+// The same as UnpackConstraint, but specialized for a pair of types as opposed to packs.
+struct Unpack1Constraint
+{
+    TypeId resultType;
+    TypeId sourceType;
+
+    // UnpackConstraint is sometimes used to resolve the types of assignments.
+    // When this is the case, any LocalTypes in resultPack can have their
+    // domains extended by the corresponding type from sourcePack.
+    bool resultIsLValue = false;
+};
+
 // resultType ~ T0 op T1 op ... op TN
 //
 // op is either union or intersection.  If any of the input types are blocked,
@@ -290,8 +303,8 @@ struct ReducePackConstraint
 
 using ConstraintV = Variant<SubtypeConstraint, PackSubtypeConstraint, GeneralizationConstraint, InstantiationConstraint, IterableConstraint,
     NameConstraint, TypeAliasExpansionConstraint, FunctionCallConstraint, FunctionCheckConstraint, PrimitiveTypeConstraint, HasPropConstraint,
-    SetPropConstraint, HasIndexerConstraint, SetIndexerConstraint, SingletonOrTopTypeConstraint, UnpackConstraint, SetOpConstraint, ReduceConstraint, ReducePackConstraint,
-    EqualityConstraint>;
+    SetPropConstraint, HasIndexerConstraint, SetIndexerConstraint, SingletonOrTopTypeConstraint, UnpackConstraint, Unpack1Constraint,
+    SetOpConstraint, ReduceConstraint, ReducePackConstraint, EqualityConstraint>;
 
 struct Constraint
 {

diff --git a/Analysis/include/Luau/ConstraintGenerator.h b/Analysis/include/Luau/ConstraintGenerator.h
@@ -95,6 +95,10 @@ struct ConstraintGenerator
     // will enqueue them during solving.
     std::vector<ConstraintPtr> unqueuedConstraints;
 
+    // Type family instances created by the generator. This is used to ensure
+    // that these instances are reduced fully by the solver.
+    std::vector<TypeId> familyInstances;
+
     // The private scope of type aliases for which the type parameters belong to.
     DenseHashMap<const AstStatTypeAlias*, ScopePtr> astTypeAliasDefiningScopes{nullptr};
 
@@ -254,16 +258,18 @@ struct ConstraintGenerator
     Inference check(const ScopePtr& scope, AstExprTable* expr, std::optional<TypeId> expectedType);
     std::tuple<TypeId, TypeId, RefinementId> checkBinary(const ScopePtr& scope, AstExprBinary* binary, std::optional<TypeId> expectedType);
 
-    /**
-     * Generate constraints to assign assignedTy to the expression expr
-     * @returns the type of the expression.  This may or may not be assignedTy itself.
-     */
-    std::optional<TypeId> checkLValue(const ScopePtr& scope, AstExpr* expr, TypeId assignedTy, bool transform);
-    std::optional<TypeId> checkLValue(const ScopePtr& scope, AstExprLocal* local, TypeId assignedTy, bool transform);
-    std::optional<TypeId> checkLValue(const ScopePtr& scope, AstExprGlobal* global, TypeId assignedTy);
-    std::optional<TypeId> checkLValue(const ScopePtr& scope, AstExprIndexName* indexName, TypeId assignedTy);
-    std::optional<TypeId> checkLValue(const ScopePtr& scope, AstExprIndexExpr* indexExpr, TypeId assignedTy);
-    TypeId updateProperty(const ScopePtr& scope, AstExpr* expr, TypeId assignedTy);
+    struct LValueBounds
+    {
+        std::optional<TypeId> annotationTy;
+        std::optional<TypeId> assignedTy;
+    };
+
+    LValueBounds checkLValue(const ScopePtr& scope, AstExpr* expr, bool transform);
+    LValueBounds checkLValue(const ScopePtr& scope, AstExprLocal* local, bool transform);
+    LValueBounds checkLValue(const ScopePtr& scope, AstExprGlobal* global);
+    LValueBounds checkLValue(const ScopePtr& scope, AstExprIndexName* indexName);
+    LValueBounds checkLValue(const ScopePtr& scope, AstExprIndexExpr* indexExpr);
+    LValueBounds updateProperty(const ScopePtr& scope, AstExpr* expr);
 
     struct FunctionSignature
     {
@@ -370,6 +376,8 @@ struct ConstraintGenerator
      *  yields a vector of size 1, with value: [number | string]
      */
     std::vector<std::optional<TypeId>> getExpectedCallTypesForFunctionOverloads(const TypeId fnType);
+
+    TypeId createFamilyInstance(TypeFamilyInstanceType instance, const ScopePtr& scope, Location location);
 };
 
 /** Borrow a vector of pointers from a vector of owning pointers to constraints.

diff --git a/Analysis/include/Luau/ConstraintSolver.h b/Analysis/include/Luau/ConstraintSolver.h
@@ -25,6 +25,8 @@ enum class ValueContext;
 
 struct DcrLogger;
 
+class AstExpr;
+
 // TypeId, TypePackId, or Constraint*. It is impossible to know which, but we
 // never dereference this pointer.
 using BlockedConstraintId = Variant<TypeId, TypePackId, const Constraint*>;
@@ -73,6 +75,9 @@ struct ConstraintSolver
     // A constraint can be both blocked and unsolved, for instance.
     std::vector<NotNull<const Constraint>> unsolvedConstraints;
 
+    // This is a set of type families that need to be reduced after all constraints have been dispatched.
+    DenseHashSet<TypeId> familyInstances{nullptr};
+
     // A mapping of constraint pointer to how many things the constraint is
     // blocked on. Can be empty or 0 for constraints that are not blocked on
     // anything.
@@ -130,14 +135,23 @@ struct ConstraintSolver
     bool tryDispatch(const FunctionCheckConstraint& c, NotNull<const Constraint> constraint);
     bool tryDispatch(const PrimitiveTypeConstraint& c, NotNull<const Constraint> constraint);
     bool tryDispatch(const HasPropConstraint& c, NotNull<const Constraint> constraint);
-    bool tryDispatch(const SetPropConstraint& c, NotNull<const Constraint> constraint, bool force);
+    bool tryDispatch(const SetPropConstraint& c, NotNull<const Constraint> constraint);
 
     bool tryDispatchHasIndexer(int& recursionDepth, NotNull<const Constraint> constraint, TypeId subjectType, TypeId indexType, TypeId resultType);
     bool tryDispatch(const HasIndexerConstraint& c, NotNull<const Constraint> constraint);
 
+    /// (dispatched, found) where
+    /// - dispatched: this constraint can be considered having dispatched.
+    /// - found: true if adding an indexer for a particular type was allowed.
+    std::pair<bool, bool> tryDispatchSetIndexer(NotNull<const Constraint> constraint, TypeId subjectType, TypeId indexType, TypeId propType, bool expandFreeTypeBounds);
     bool tryDispatch(const SetIndexerConstraint& c, NotNull<const Constraint> constraint, bool force);
+
     bool tryDispatch(const SingletonOrTopTypeConstraint& c, NotNull<const Constraint> constraint);
+
+    bool tryDispatchUnpack1(NotNull<const Constraint> constraint, TypeId resultType, TypeId sourceType, bool resultIsLValue);
     bool tryDispatch(const UnpackConstraint& c, NotNull<const Constraint> constraint);
+    bool tryDispatch(const Unpack1Constraint& c, NotNull<const Constraint> constraint);
+
     bool tryDispatch(const SetOpConstraint& c, NotNull<const Constraint> constraint, bool force);
     bool tryDispatch(const ReduceConstraint& c, NotNull<const Constraint> constraint, bool force);
     bool tryDispatch(const ReducePackConstraint& c, NotNull<const Constraint> constraint, bool force);
@@ -151,10 +165,10 @@ struct ConstraintSolver
     bool tryDispatchIterableFunction(
         TypeId nextTy, TypeId tableTy, TypeId firstIndexTy, const IterableConstraint& c, NotNull<const Constraint> constraint, bool force);
 
-    std::pair<std::vector<TypeId>, std::optional<TypeId>> lookupTableProp(
-        TypeId subjectType, const std::string& propName, ValueContext context, bool inConditional = false, bool suppressSimplification = false);
-    std::pair<std::vector<TypeId>, std::optional<TypeId>> lookupTableProp(
-        TypeId subjectType, const std::string& propName, ValueContext context, bool inConditional, bool suppressSimplification, DenseHashSet<TypeId>& seen);
+    std::pair<std::vector<TypeId>, std::optional<TypeId>> lookupTableProp(NotNull<const Constraint> constraint, TypeId subjectType,
+        const std::string& propName, ValueContext context, bool inConditional = false, bool suppressSimplification = false);
+    std::pair<std::vector<TypeId>, std::optional<TypeId>> lookupTableProp(NotNull<const Constraint> constraint, TypeId subjectType,
+        const std::string& propName, ValueContext context, bool inConditional, bool suppressSimplification, DenseHashSet<TypeId>& seen);
 
     void block(NotNull<const Constraint> target, NotNull<const Constraint> constraint);
     /**
@@ -242,17 +256,6 @@ struct ConstraintSolver
      */
     bool hasUnresolvedConstraints(TypeId ty);
 
-    /**
-     * Creates a new Unifier and performs a single unification operation.
-     *
-     * @param subType the sub-type to unify.
-     * @param superType the super-type to unify.
-     * @returns true if the unification succeeded.  False if the unification was
-     * too complex.
-     */
-    template <typename TID>
-    bool unify(NotNull<Scope> scope, Location location, TID subType, TID superType);
-
     /** Attempts to unify subTy with superTy.  If doing so would require unifying
      * BlockedTypes, fail and block the constraint on those BlockedTypes.
      *

diff --git a/Analysis/include/Luau/Type.h b/Analysis/include/Luau/Type.h
@@ -299,6 +299,7 @@ using MagicFunction = std::function<std::optional<WithPredicate<TypePackId>>(
 struct MagicFunctionCallContext
 {
     NotNull<struct ConstraintSolver> solver;
+    NotNull<const Constraint> constraint;
     const class AstExprCall* callSite;
     TypePackId arguments;
     TypePackId result;

diff --git a/Analysis/include/Luau/TypeFamilyReductionGuesser.h b/Analysis/include/Luau/TypeFamilyReductionGuesser.h
@@ -13,6 +13,7 @@
 #include "Luau/TypeFwd.h"
 #include "Luau/VisitType.h"
 #include "Luau/NotNull.h"
+#include "TypeArena.h"
 
 namespace Luau
 {
@@ -42,11 +43,14 @@ struct TypeFamilyReductionGuesser
     DenseHashSet<TypeId> cyclicInstances{nullptr};
 
     // Utilities
+    NotNull<TypeArena> arena;
     NotNull<BuiltinTypes> builtins;
     NotNull<Normalizer> normalizer;
 
-    TypeFamilyReductionGuesser(NotNull<BuiltinTypes> builtins, NotNull<Normalizer> normalizer);
+    TypeFamilyReductionGuesser(NotNull<TypeArena> arena, NotNull<BuiltinTypes> builtins, NotNull<Normalizer> normalizer);
 
+    std::optional<TypeId> guess(TypeId typ);
+    std::optional<TypePackId> guess(TypePackId typ);
     TypeFamilyReductionGuessResult guessTypeFamilyReductionForFunction(const AstExprFunction& expr, const FunctionType* ftv, TypeId retTy);
 
 private:

diff --git a/Analysis/include/Luau/Unifier2.h b/Analysis/include/Luau/Unifier2.h
@@ -2,11 +2,12 @@
 
 #pragma once
 
+#include "Luau/Constraint.h"
 #include "Luau/DenseHash.h"
 #include "Luau/NotNull.h"
-#include "Luau/TypePairHash.h"
 #include "Luau/TypeCheckLimits.h"
 #include "Luau/TypeFwd.h"
+#include "Luau/TypePairHash.h"
 
 #include <optional>
 #include <vector>
@@ -46,6 +47,8 @@ struct Unifier2
     int recursionCount = 0;
     int recursionLimit = 0;
 
+    std::vector<ConstraintV> incompleteSubtypes;
+
     Unifier2(NotNull<TypeArena> arena, NotNull<BuiltinTypes> builtinTypes, NotNull<Scope> scope, NotNull<InternalErrorReporter> ice);
 
     /** Attempt to commit the subtype relation subTy <: superTy to the type
@@ -61,6 +64,7 @@ struct Unifier2
      * free TypePack to another and encounter an occurs check violation.
      */
     bool unify(TypeId subTy, TypeId superTy);
+    bool unifyFreeWithType(TypeId subTy, TypeId superTy);
     bool unify(const LocalType* subTy, TypeId superFn);
     bool unify(TypeId subTy, const FunctionType* superFn);
     bool unify(const UnionType* subUnion, TypeId superTy);

diff --git a/Analysis/include/Luau/VisitType.h b/Analysis/include/Luau/VisitType.h
@@ -64,6 +64,9 @@ inline void unsee(DenseHashSet<void*>& seen, const void* tv)
 
 } // namespace visit_detail
 
+// recursion counter is equivalent here, but we'd like a better name to express the intent.
+using TypeFamilyDepthCounter = RecursionCounter;
+
 template<typename S>
 struct GenericTypeVisitor
 {
@@ -72,6 +75,7 @@ struct GenericTypeVisitor
     Set seen;
     bool skipBoundTypes = false;
     int recursionCounter = 0;
+    int typeFamilyDepth = 0;
 
     GenericTypeVisitor() = default;
 
@@ -400,6 +404,8 @@ struct GenericTypeVisitor
         }
         else if (auto tfit = get<TypeFamilyInstanceType>(ty))
         {
+            TypeFamilyDepthCounter tfdc{&typeFamilyDepth};
+
             if (visit(ty, *tfit))
             {
                 for (TypeId p : tfit->typeArguments)
@@ -460,6 +466,8 @@ struct GenericTypeVisitor
             visit(tp, *btp);
         else if (auto tfitp = get<TypeFamilyInstanceTypePack>(tp))
         {
+            TypeFamilyDepthCounter tfdc{&typeFamilyDepth};
+
             if (visit(tp, *tfitp))
             {
                 for (TypeId t : tfitp->typeArguments)

diff --git a/Analysis/src/BuiltinDefinitions.cpp b/Analysis/src/BuiltinDefinitions.cpp
@@ -431,7 +431,7 @@ static bool dcrMagicFunctionFormat(MagicFunctionCallContext context)
     // unify the prefix one argument at a time
     for (size_t i = 0; i < expected.size() && i + paramOffset < params.size(); ++i)
     {
-        context.solver->unify(context.solver->rootScope, context.callSite->location, params[i + paramOffset], expected[i]);
+        context.solver->unify(context.constraint, params[i + paramOffset], expected[i]);
     }
 
     // if we know the argument count or if we have too many arguments for sure, we can issue an error
@@ -561,7 +561,7 @@ static bool dcrMagicFunctionGmatch(MagicFunctionCallContext context)
     if (returnTypes.empty())
         return false;
 
-    context.solver->unify(context.solver->rootScope, context.callSite->location, params[0], context.solver->builtinTypes->stringType);
+    context.solver->unify(context.constraint, params[0], context.solver->builtinTypes->stringType);
 
     const TypePackId emptyPack = arena->addTypePack({});
     const TypePackId returnList = arena->addTypePack(returnTypes);
@@ -630,13 +630,13 @@ static bool dcrMagicFunctionMatch(MagicFunctionCallContext context)
     if (returnTypes.empty())
         return false;
 
-    context.solver->unify(context.solver->rootScope, context.callSite->location, params[0], context.solver->builtinTypes->stringType);
+    context.solver->unify(context.constraint, params[0], context.solver->builtinTypes->stringType);
 
     const TypeId optionalNumber = arena->addType(UnionType{{context.solver->builtinTypes->nilType, context.solver->builtinTypes->numberType}});
 
     size_t initIndex = context.callSite->self ? 1 : 2;
     if (params.size() == 3 && context.callSite->args.size > initIndex)
-        context.solver->unify(context.solver->rootScope, context.callSite->location, params[2], optionalNumber);
+        context.solver->unify(context.constraint, params[2], optionalNumber);
 
     const TypePackId returnList = arena->addTypePack(returnTypes);
     asMutable(context.result)->ty.emplace<BoundTypePack>(returnList);
@@ -733,17 +733,17 @@ static bool dcrMagicFunctionFind(MagicFunctionCallContext context)
             return false;
     }
 
-    context.solver->unify(context.solver->rootScope, context.callSite->location, params[0], builtinTypes->stringType);
+    context.solver->unify(context.constraint, params[0], builtinTypes->stringType);
 
     const TypeId optionalNumber = arena->addType(UnionType{{builtinTypes->nilType, builtinTypes->numberType}});
     const TypeId optionalBoolean = arena->addType(UnionType{{builtinTypes->nilType, builtinTypes->booleanType}});
 
     size_t initIndex = context.callSite->self ? 1 : 2;
     if (params.size() >= 3 && context.callSite->args.size > initIndex)
-        context.solver->unify(context.solver->rootScope, context.callSite->location, params[2], optionalNumber);
+        context.solver->unify(context.constraint, params[2], optionalNumber);
 
     if (params.size() == 4 && context.callSite->args.size > plainIndex)
-        context.solver->unify(context.solver->rootScope, context.callSite->location, params[3], optionalBoolean);
+        context.solver->unify(context.constraint, params[3], optionalBoolean);
 
     returnTypes.insert(returnTypes.begin(), {optionalNumber, optionalNumber});