Sync to upstream/release/516

Analysis/include/Luau/Module.h

@@ -13,8 +13,6 @@
 #include <unordered_map>
 #include <optional>
 
-LUAU_FASTFLAG(LuauPrepopulateUnionOptionsBeforeAllocation)
-
 namespace Luau
 {
 
@@ -60,11 +58,8 @@ struct TypeArena
     template<typename T>
     TypeId addType(T tv)
     {
-        if (FFlag::LuauPrepopulateUnionOptionsBeforeAllocation)
+        if constexpr (std::is_same_v<T, UnionTypeVar>)
-        {
+            LUAU_ASSERT(tv.options.size() >= 2);
-            if constexpr (std::is_same_v<T, UnionTypeVar>)
-                LUAU_ASSERT(tv.options.size() >= 2);
-        }
 
         return addTV(TypeVar(std::move(tv)));
     }

Analysis/include/Luau/TypeInfer.h

@@ -31,6 +31,7 @@ bool doesCallError(const AstExprCall* call);
 bool hasBreak(AstStat* node);
 const AstStat* getFallthrough(const AstStat* node);
 
+struct UnifierOptions;
 struct Unifier;
 
 // A substitution which replaces generic types in a given set by free types.
@@ -245,6 +246,7 @@ struct TypeChecker
      * Treat any failures as type errors in the final typecheck report.
      */
     bool unify(TypeId subTy, TypeId superTy, const Location& location);
+    bool unify(TypeId subTy, TypeId superTy, const Location& location, const UnifierOptions& options);
     bool unify(TypePackId subTy, TypePackId superTy, const Location& location, CountMismatch::Context ctx = CountMismatch::Context::Arg);
 
     /** Attempt to unify the types.

Analysis/include/Luau/TypeUtils.h

@@ -13,7 +13,7 @@ namespace Luau
 
 using ScopePtr = std::shared_ptr<struct Scope>;
 
-std::optional<TypeId> findMetatableEntry(ErrorVec& errors, const ScopePtr& globalScope, TypeId type, std::string entry, Location location);
+std::optional<TypeId> findMetatableEntry(ErrorVec& errors, TypeId type, std::string entry, Location location);
-std::optional<TypeId> findTablePropertyRespectingMeta(ErrorVec& errors, const ScopePtr& globalScope, TypeId ty, Name name, Location location);
+std::optional<TypeId> findTablePropertyRespectingMeta(ErrorVec& errors, TypeId ty, Name name, Location location);
 
 } // namespace Luau

Analysis/include/Luau/Unifier.h

@@ -19,11 +19,31 @@ enum Variance
     Invariant
 };
 
+// A substitution which replaces singleton types by their wider types
+struct Widen : Substitution
+{
+    Widen(TypeArena* arena)
+        : Substitution(TxnLog::empty(), arena)
+    {
+    }
+
+    bool isDirty(TypeId ty) override;
+    bool isDirty(TypePackId ty) override;
+    TypeId clean(TypeId ty) override;
+    TypePackId clean(TypePackId ty) override;
+    bool ignoreChildren(TypeId ty) override;
+};
+
+// TODO: Use this more widely.
+struct UnifierOptions
+{
+    bool isFunctionCall = false;
+};
+
 struct Unifier
 {
     TypeArena* const types;
     Mode mode;
-    ScopePtr globalScope; // sigh.  Needed solely to get at string's metatable.
 
     DEPRECATED_TxnLog DEPRECATED_log;
     TxnLog log;
@@ -34,9 +54,9 @@ struct Unifier
 
     UnifierSharedState& sharedState;
 
-    Unifier(TypeArena* types, Mode mode, ScopePtr globalScope, const Location& location, Variance variance, UnifierSharedState& sharedState,
+    Unifier(TypeArena* types, Mode mode, const Location& location, Variance variance, UnifierSharedState& sharedState,
         TxnLog* parentLog = nullptr);
-    Unifier(TypeArena* types, Mode mode, ScopePtr globalScope, std::vector<std::pair<TypeId, TypeId>>* sharedSeen, const Location& location,
+    Unifier(TypeArena* types, Mode mode, std::vector<std::pair<TypeId, TypeId>>* sharedSeen, const Location& location,
         Variance variance, UnifierSharedState& sharedState, TxnLog* parentLog = nullptr);
 
     // Test whether the two type vars unify.  Never commits the result.
@@ -65,7 +85,10 @@ private:
     void tryUnifyWithMetatable(TypeId subTy, TypeId superTy, bool reversed);
     void tryUnifyWithClass(TypeId subTy, TypeId superTy, bool reversed);
     void tryUnifyIndexer(const TableIndexer& subIndexer, const TableIndexer& superIndexer);
+
+    TypeId widen(TypeId ty);
     TypeId deeplyOptional(TypeId ty, std::unordered_map<TypeId, TypeId> seen = {});
+
     void cacheResult(TypeId subTy, TypeId superTy);
 
 public:

Analysis/src/Autocomplete.cpp

@@ -236,10 +236,10 @@ static TypeCorrectKind checkTypeCorrectKind(const Module& module, TypeArena* typ
 {
     ty = follow(ty);
 
-    auto canUnify = [&typeArena, &module](TypeId subTy, TypeId superTy) {
+    auto canUnify = [&typeArena](TypeId subTy, TypeId superTy) {
         InternalErrorReporter iceReporter;
         UnifierSharedState unifierState(&iceReporter);
-        Unifier unifier(typeArena, Mode::Strict, module.getModuleScope(), Location(), Variance::Covariant, unifierState);
+        Unifier unifier(typeArena, Mode::Strict, Location(), Variance::Covariant, unifierState);
 
         if (FFlag::LuauAutocompleteAvoidMutation && !FFlag::LuauUseCommittingTxnLog)
         {

Analysis/src/Linter.cpp

@@ -201,6 +201,7 @@ static bool similar(AstExpr* lhs, AstExpr* rhs)
 
         return true;
     }
+    CASE(AstExprIfElse) return similar(le->condition, re->condition) && similar(le->trueExpr, re->trueExpr) && similar(le->falseExpr, re->falseExpr);
     else
     {
         LUAU_ASSERT(!"Unknown expression type");

Analysis/src/Module.cpp

@@ -16,7 +16,6 @@ LUAU_FASTFLAGVARIABLE(DebugLuauTrackOwningArena, false) // Remove with FFlagLuau
 LUAU_FASTINTVARIABLE(LuauTypeCloneRecursionLimit, 300)
 LUAU_FASTFLAG(LuauTypeAliasDefaults)
 LUAU_FASTFLAG(LuauImmutableTypes)
-LUAU_FASTFLAGVARIABLE(LuauPrepopulateUnionOptionsBeforeAllocation, false)
 
 namespace Luau
 {
@@ -379,28 +378,14 @@ void TypeCloner::operator()(const AnyTypeVar& t)
 
 void TypeCloner::operator()(const UnionTypeVar& t)
 {
-    if (FFlag::LuauPrepopulateUnionOptionsBeforeAllocation)
+    std::vector<TypeId> options;
-    {
+    options.reserve(t.options.size());
-        std::vector<TypeId> options;
-        options.reserve(t.options.size());
 
-        for (TypeId ty : t.options)
+    for (TypeId ty : t.options)
-            options.push_back(clone(ty, dest, seenTypes, seenTypePacks, cloneState));
+        options.push_back(clone(ty, dest, seenTypes, seenTypePacks, cloneState));
 
-        TypeId result = dest.addType(UnionTypeVar{std::move(options)});
+    TypeId result = dest.addType(UnionTypeVar{std::move(options)});
-        seenTypes[typeId] = result;
+    seenTypes[typeId] = result;
-    }
-    else
-    {
-        TypeId result = dest.addType(UnionTypeVar{});
-        seenTypes[typeId] = result;
-
-        UnionTypeVar* option = getMutable<UnionTypeVar>(result);
-        LUAU_ASSERT(option != nullptr);
-
-        for (TypeId ty : t.options)
-            option->options.push_back(clone(ty, dest, seenTypes, seenTypePacks, cloneState));
-    }
 }
 
 void TypeCloner::operator()(const IntersectionTypeVar& t)

Analysis/src/Transpiler.cpp

@@ -1153,6 +1153,14 @@ struct Printer
                     writer.symbol(")");
             }
         }
+        else if (const auto& a = typeAnnotation.as<AstTypeSingletonBool>())
+        {
+            writer.keyword(a->value ? "true" : "false");
+        }
+        else if (const auto& a = typeAnnotation.as<AstTypeSingletonString>())
+        {
+            writer.string(std::string_view(a->value.data, a->value.size));
+        }
         else if (typeAnnotation.is<AstTypeError>())
         {
             writer.symbol("%error-type%");

Analysis/src/TypeInfer.cpp

@@ -29,7 +29,6 @@ LUAU_FASTFLAGVARIABLE(DebugLuauFreezeDuringUnification, false)
 LUAU_FASTFLAGVARIABLE(LuauRecursiveTypeParameterRestriction, false)
 LUAU_FASTFLAGVARIABLE(LuauGenericFunctionsDontCacheTypeParams, false)
 LUAU_FASTFLAGVARIABLE(LuauImmutableTypes, false)
-LUAU_FASTFLAGVARIABLE(LuauNoSealedTypeMod, false)
 LUAU_FASTFLAGVARIABLE(LuauQuantifyInPlace2, false)
 LUAU_FASTFLAGVARIABLE(LuauSealExports, false)
 LUAU_FASTFLAGVARIABLE(LuauSingletonTypes, false)
@@ -38,14 +37,14 @@ LUAU_FASTFLAGVARIABLE(LuauTypeAliasDefaults, false)
 LUAU_FASTFLAGVARIABLE(LuauExpectedTypesOfProperties, false)
 LUAU_FASTFLAGVARIABLE(LuauErrorRecoveryType, false)
 LUAU_FASTFLAGVARIABLE(LuauPropertiesGetExpectedType, false)
-LUAU_FASTFLAGVARIABLE(LuauProperTypeLevels, false)
 LUAU_FASTFLAGVARIABLE(LuauAscribeCorrectLevelToInferredProperitesOfFreeTables, false)
-LUAU_FASTFLAG(LuauUnionTagMatchFix)
 LUAU_FASTFLAGVARIABLE(LuauUnsealedTableLiteral, false)
 LUAU_FASTFLAGVARIABLE(LuauTwoPassAliasDefinitionFix, false)
 LUAU_FASTFLAGVARIABLE(LuauAssertStripsFalsyTypes, false)
 LUAU_FASTFLAGVARIABLE(LuauReturnAnyInsteadOfICE, false) // Eventually removed as false.
 LUAU_FASTFLAGVARIABLE(LuauAnotherTypeLevelFix, false)
+LUAU_FASTFLAG(LuauWidenIfSupertypeIsFree)
+LUAU_FASTFLAGVARIABLE(LuauDoNotTryToReduce, false)
 
 namespace Luau
 {
@@ -1125,7 +1124,7 @@ void TypeChecker::check(const ScopePtr& scope, TypeId ty, const ScopePtr& funSco
 
         ty = follow(ty);
 
-        if (tableSelf && (FFlag::LuauNoSealedTypeMod ? tableSelf->state != TableState::Sealed : !selfTy->persistent))
+        if (tableSelf && tableSelf->state != TableState::Sealed)
             tableSelf->props[indexName->index.value] = {ty, /* deprecated */ false, {}, indexName->indexLocation};
 
         const FunctionTypeVar* funTy = get<FunctionTypeVar>(ty);
@@ -1138,7 +1137,7 @@ void TypeChecker::check(const ScopePtr& scope, TypeId ty, const ScopePtr& funSco
 
         checkFunctionBody(funScope, ty, *function.func);
 
-        if (tableSelf && (FFlag::LuauNoSealedTypeMod ? tableSelf->state != TableState::Sealed : !selfTy->persistent))
+        if (tableSelf && tableSelf->state != TableState::Sealed)
             tableSelf->props[indexName->index.value] = {
                 follow(quantify(funScope, ty, indexName->indexLocation)), /* deprecated */ false, {}, indexName->indexLocation};
     }
@@ -1210,8 +1209,7 @@ void TypeChecker::check(const ScopePtr& scope, const AstStatTypeAlias& typealias
         {
             ScopePtr aliasScope = childScope(scope, typealias.location);
             aliasScope->level = scope->level.incr();
-            if (FFlag::LuauProperTypeLevels)
+            aliasScope->level.subLevel = subLevel;
-                aliasScope->level.subLevel = subLevel;
 
             auto [generics, genericPacks] =
                 createGenericTypes(aliasScope, scope->level, typealias, typealias.generics, typealias.genericPacks, /* useCache = */ true);
@@ -1624,7 +1622,7 @@ ExprResult<TypeId> TypeChecker::checkExpr(const ScopePtr& scope, const AstExprIn
 std::optional<TypeId> TypeChecker::findTablePropertyRespectingMeta(TypeId lhsType, Name name, const Location& location)
 {
     ErrorVec errors;
-    auto result = Luau::findTablePropertyRespectingMeta(errors, globalScope, lhsType, name, location);
+    auto result = Luau::findTablePropertyRespectingMeta(errors, lhsType, name, location);
     reportErrors(errors);
     return result;
 }
@@ -1632,7 +1630,7 @@ std::optional<TypeId> TypeChecker::findTablePropertyRespectingMeta(TypeId lhsTyp
 std::optional<TypeId> TypeChecker::findMetatableEntry(TypeId type, std::string entry, const Location& location)
 {
     ErrorVec errors;
-    auto result = Luau::findMetatableEntry(errors, globalScope, type, entry, location);
+    auto result = Luau::findMetatableEntry(errors, type, entry, location);
     reportErrors(errors);
     return result;
 }
@@ -1751,13 +1749,23 @@ std::optional<TypeId> TypeChecker::getIndexTypeFromType(
             return std::nullopt;
         }
 
-        // TODO(amccord): Write some logic to correctly handle intersections. CLI-34659
+        if (FFlag::LuauDoNotTryToReduce)
-        std::vector<TypeId> result = reduceUnion(parts);
+        {
+            if (parts.size() == 1)
+                return parts[0];
 
-        if (result.size() == 1)
+            return addType(IntersectionTypeVar{std::move(parts)}); // Not at all correct.
-            return result[0];
+        }
+        else
+        {
+            // TODO(amccord): Write some logic to correctly handle intersections. CLI-34659
+            std::vector<TypeId> result = reduceUnion(parts);
 
-        return addType(IntersectionTypeVar{result});
+            if (result.size() == 1)
+                return result[0];
+
+            return addType(IntersectionTypeVar{result});
+        }
     }
 
     if (addErrors)
@@ -2823,10 +2831,7 @@ TypeId TypeChecker::checkLValueBinding(const ScopePtr& scope, const AstExprIndex
 TypeId TypeChecker::checkFunctionName(const ScopePtr& scope, AstExpr& funName, TypeLevel level)
 {
     auto freshTy = [&]() {
-        if (FFlag::LuauProperTypeLevels)
+        return freshType(level);
-            return freshType(level);
-        else
-            return freshType(scope);
     };
 
     if (auto globalName = funName.as<AstExprGlobal>())
@@ -3790,7 +3795,14 @@ std::optional<ExprResult<TypePackId>> TypeChecker::checkCallOverload(const Scope
         // has been instantiated, so is a monotype. We can therefore
         // unify it with a monomorphic function.
         TypeId r = addType(FunctionTypeVar(scope->level, argPack, retPack));
-        unify(fn, r, expr.location);
+        if (FFlag::LuauWidenIfSupertypeIsFree)
+        {
+            UnifierOptions options;
+            options.isFunctionCall = true;
+            unify(r, fn, expr.location, options);
+        }
+        else
+            unify(fn, r, expr.location);
         return {{retPack}};
     }
 
@@ -4243,9 +4255,15 @@ TypeId TypeChecker::anyIfNonstrict(TypeId ty) const
 }
 
 bool TypeChecker::unify(TypeId subTy, TypeId superTy, const Location& location)
+{
+    UnifierOptions options;
+    return unify(subTy, superTy, location, options);
+}
+
+bool TypeChecker::unify(TypeId subTy, TypeId superTy, const Location& location, const UnifierOptions& options)
 {
     Unifier state = mkUnifier(location);
-    state.tryUnify(subTy, superTy);
+    state.tryUnify(subTy, superTy, options.isFunctionCall);
 
     if (FFlag::LuauUseCommittingTxnLog)
         state.log.commit();
@@ -4654,7 +4672,7 @@ void TypeChecker::diagnoseMissingTableKey(UnknownProperty* utk, TypeErrorData& d
         }
     };
 
-    if (auto ttv = getTableType(FFlag::LuauUnionTagMatchFix ? utk->table : follow(utk->table)))
+    if (auto ttv = getTableType(utk->table))
         accumulate(ttv->props);
     else if (auto ctv = get<ClassTypeVar>(follow(utk->table)))
     {
@@ -4691,8 +4709,7 @@ ScopePtr TypeChecker::childFunctionScope(const ScopePtr& parent, const Location&
 ScopePtr TypeChecker::childScope(const ScopePtr& parent, const Location& location)
 {
     ScopePtr scope = std::make_shared<Scope>(parent);
-    if (FFlag::LuauProperTypeLevels)
+    scope->level = parent->level;
-        scope->level = parent->level;
     scope->varargPack = parent->varargPack;
 
     currentModule->scopes.push_back(std::make_pair(location, scope));
@@ -4724,7 +4741,7 @@ void TypeChecker::merge(RefinementMap& l, const RefinementMap& r)
 
 Unifier TypeChecker::mkUnifier(const Location& location)
 {
-    return Unifier{&currentModule->internalTypes, currentModule->mode, globalScope, location, Variance::Covariant, unifierState};
+    return Unifier{&currentModule->internalTypes, currentModule->mode, location, Variance::Covariant, unifierState};
 }
 
 TypeId TypeChecker::freshType(const ScopePtr& scope)
@@ -5444,7 +5461,7 @@ GenericTypeDefinitions TypeChecker::createGenericTypes(const ScopePtr& scope, st
 
 void TypeChecker::refineLValue(const LValue& lvalue, RefinementMap& refis, const ScopePtr& scope, TypeIdPredicate predicate)
 {
-    LUAU_ASSERT(FFlag::LuauDiscriminableUnions2);
+    LUAU_ASSERT(FFlag::LuauDiscriminableUnions2 || FFlag::LuauAssertStripsFalsyTypes);
 
     const LValue* target = &lvalue;
     std::optional<LValue> key; // If set, we know we took the base of the lvalue path and should be walking down each option of the base's type.

Analysis/src/TypeUtils.cpp

@@ -10,7 +10,7 @@ LUAU_FASTFLAGVARIABLE(LuauTerminateCyclicMetatableIndexLookup, false)
 namespace Luau
 {
 
-std::optional<TypeId> findMetatableEntry(ErrorVec& errors, const ScopePtr& globalScope, TypeId type, std::string entry, Location location)
+std::optional<TypeId> findMetatableEntry(ErrorVec& errors, TypeId type, std::string entry, Location location)
 {
     type = follow(type);
 
@@ -37,7 +37,7 @@ std::optional<TypeId> findMetatableEntry(ErrorVec& errors, const ScopePtr& globa
         return std::nullopt;
 }
 
-std::optional<TypeId> findTablePropertyRespectingMeta(ErrorVec& errors, const ScopePtr& globalScope, TypeId ty, Name name, Location location)
+std::optional<TypeId> findTablePropertyRespectingMeta(ErrorVec& errors, TypeId ty, Name name, Location location)
 {
     if (get<AnyTypeVar>(ty))
         return ty;
@@ -49,7 +49,7 @@ std::optional<TypeId> findTablePropertyRespectingMeta(ErrorVec& errors, const Sc
             return it->second.type;
     }
 
-    std::optional<TypeId> mtIndex = findMetatableEntry(errors, globalScope, ty, "__index", location);
+    std::optional<TypeId> mtIndex = findMetatableEntry(errors, ty, "__index", location);
     int count = 0;
     while (mtIndex)
     {
@@ -82,7 +82,7 @@ std::optional<TypeId> findTablePropertyRespectingMeta(ErrorVec& errors, const Sc
         else
             errors.push_back(TypeError{location, GenericError{"__index should either be a function or table. Got " + toString(index)}});
 
-        mtIndex = findMetatableEntry(errors, globalScope, *mtIndex, "__index", location);
+        mtIndex = findMetatableEntry(errors, *mtIndex, "__index", location);
     }
 
     return std::nullopt;

Analysis/src/TypeVar.cpp

@@ -23,9 +23,7 @@ LUAU_FASTFLAG(DebugLuauFreezeArena)
 LUAU_FASTINTVARIABLE(LuauTypeMaximumStringifierLength, 500)
 LUAU_FASTINTVARIABLE(LuauTableTypeMaximumStringifierLength, 0)
 LUAU_FASTINT(LuauTypeInferRecursionLimit)
-LUAU_FASTFLAGVARIABLE(LuauRefactorTypeVarQuestions, false)
 LUAU_FASTFLAG(LuauErrorRecoveryType)
-LUAU_FASTFLAG(LuauUnionTagMatchFix)
 LUAU_FASTFLAG(LuauDiscriminableUnions2)
 
 namespace Luau
@@ -145,20 +143,13 @@ bool isNil(TypeId ty)
 
 bool isBoolean(TypeId ty)
 {
-    if (FFlag::LuauRefactorTypeVarQuestions)
+    if (isPrim(ty, PrimitiveTypeVar::Boolean) || get<BooleanSingleton>(get<SingletonTypeVar>(follow(ty))))
-    {
+        return true;
-        if (isPrim(ty, PrimitiveTypeVar::Boolean) || get<BooleanSingleton>(get<SingletonTypeVar>(follow(ty))))
-            return true;
 
-        if (auto utv = get<UnionTypeVar>(follow(ty)))
+    if (auto utv = get<UnionTypeVar>(follow(ty)))
-            return std::all_of(begin(utv), end(utv), isBoolean);
+        return std::all_of(begin(utv), end(utv), isBoolean);
 
-        return false;
+    return false;
-    }
-    else
-    {
-        return isPrim(ty, PrimitiveTypeVar::Boolean);
-    }
 }
 
 bool isNumber(TypeId ty)
@@ -168,20 +159,13 @@ bool isNumber(TypeId ty)
 
 bool isString(TypeId ty)
 {
-    if (FFlag::LuauRefactorTypeVarQuestions)
+    if (isPrim(ty, PrimitiveTypeVar::String) || get<StringSingleton>(get<SingletonTypeVar>(follow(ty))))
-    {
+        return true;
-        if (isPrim(ty, PrimitiveTypeVar::String) || get<StringSingleton>(get<SingletonTypeVar>(follow(ty))))
-            return true;
 
-        if (auto utv = get<UnionTypeVar>(follow(ty)))
+    if (auto utv = get<UnionTypeVar>(follow(ty)))
-            return std::all_of(begin(utv), end(utv), isString);
+        return std::all_of(begin(utv), end(utv), isString);
 
-        return false;
+    return false;
-    }
-    else
-    {
-        return isPrim(ty, PrimitiveTypeVar::String);
-    }
 }
 
 bool isThread(TypeId ty)
@@ -194,45 +178,11 @@ bool isOptional(TypeId ty)
     if (isNil(ty))
         return true;
 
-    if (FFlag::LuauRefactorTypeVarQuestions)
+    auto utv = get<UnionTypeVar>(follow(ty));
-    {
+    if (!utv)
-        auto utv = get<UnionTypeVar>(follow(ty));
-        if (!utv)
-            return false;
-
-        return std::any_of(begin(utv), end(utv), isNil);
-    }
-    else
-    {
-        std::unordered_set<TypeId> seen;
-        std::deque<TypeId> queue{ty};
-        while (!queue.empty())
-        {
-            TypeId current = follow(queue.front());
-            queue.pop_front();
-
-            if (seen.count(current))
-                continue;
-
-            seen.insert(current);
-
-            if (isNil(current))
-                return true;
-
-            if (auto u = get<UnionTypeVar>(current))
-            {
-                for (TypeId option : u->options)
-                {
-                    if (isNil(option))
-                        return true;
-
-                    queue.push_back(option);
-                }
-            }
-        }
-
         return false;
-    }
+
+    return std::any_of(begin(utv), end(utv), isNil);
 }
 
 bool isTableIntersection(TypeId ty)
@@ -263,38 +213,24 @@ std::optional<TypeId> getMetatable(TypeId type)
         return mtType->metatable;
     else if (const ClassTypeVar* classType = get<ClassTypeVar>(type))
         return classType->metatable;
-    else if (FFlag::LuauRefactorTypeVarQuestions)
+    else if (isString(type))
     {
-        if (isString(type))
+        auto ptv = get<PrimitiveTypeVar>(getSingletonTypes().stringType);
-        {
+        LUAU_ASSERT(ptv && ptv->metatable);
-            auto ptv = get<PrimitiveTypeVar>(getSingletonTypes().stringType);
+        return ptv->metatable;
-            LUAU_ASSERT(ptv && ptv->metatable);
-            return ptv->metatable;
-        }
-        else
-            return std::nullopt;
-    }
-    else
-    {
-        if (const PrimitiveTypeVar* primitiveType = get<PrimitiveTypeVar>(type); primitiveType && primitiveType->metatable)
-        {
-            LUAU_ASSERT(primitiveType->type == PrimitiveTypeVar::String);
-            return primitiveType->metatable;
-        }
-        else
-            return std::nullopt;
     }
+
+    return std::nullopt;
 }
 
 const TableTypeVar* getTableType(TypeId type)
 {
-    if (FFlag::LuauUnionTagMatchFix)
+    type = follow(type);
-        type = follow(type);
 
     if (const TableTypeVar* ttv = get<TableTypeVar>(type))
         return ttv;
     else if (const MetatableTypeVar* mtv = get<MetatableTypeVar>(type))
-        return get<TableTypeVar>(FFlag::LuauUnionTagMatchFix ? follow(mtv->table) : mtv->table);
+        return get<TableTypeVar>(follow(mtv->table));
     else
         return nullptr;
 }
@@ -311,7 +247,7 @@ const std::string* getName(TypeId type)
     {
         if (mtv->syntheticName)
             return &*mtv->syntheticName;
-        type = FFlag::LuauUnionTagMatchFix ? follow(mtv->table) : mtv->table;
+        type = follow(mtv->table);
     }
 
     if (auto ttv = get<TableTypeVar>(type))

Analysis/src/Unifier.cpp

@@ -21,9 +21,8 @@ LUAU_FASTFLAGVARIABLE(LuauTableSubtypingVariance2, false);
 LUAU_FASTFLAGVARIABLE(LuauTableUnificationEarlyTest, false)
 LUAU_FASTFLAG(LuauSingletonTypes)
 LUAU_FASTFLAG(LuauErrorRecoveryType);
-LUAU_FASTFLAG(LuauProperTypeLevels);
-LUAU_FASTFLAGVARIABLE(LuauUnionTagMatchFix, false)
 LUAU_FASTFLAGVARIABLE(LuauFollowWithCommittingTxnLogInAnyUnification, false)
+LUAU_FASTFLAGVARIABLE(LuauWidenIfSupertypeIsFree, false)
 
 namespace Luau
 {
@@ -122,7 +121,7 @@ struct PromoteTypeLevels
     }
 };
 
-void promoteTypeLevels(DEPRECATED_TxnLog& DEPRECATED_log, TxnLog& log, const TypeArena* typeArena, TypeLevel minLevel, TypeId ty)
+static void promoteTypeLevels(DEPRECATED_TxnLog& DEPRECATED_log, TxnLog& log, const TypeArena* typeArena, TypeLevel minLevel, TypeId ty)
 {
     // Type levels of types from other modules are already global, so we don't need to promote anything inside
     if (FFlag::LuauImmutableTypes && ty->owningArena != typeArena)
@@ -133,6 +132,7 @@ void promoteTypeLevels(DEPRECATED_TxnLog& DEPRECATED_log, TxnLog& log, const Typ
     visitTypeVarOnce(ty, ptl, seen);
 }
 
+// TODO: use this and make it static.
 void promoteTypeLevels(DEPRECATED_TxnLog& DEPRECATED_log, TxnLog& log, const TypeArena* typeArena, TypeLevel minLevel, TypePackId tp)
 {
     // Type levels of types from other modules are already global, so we don't need to promote anything inside
@@ -247,6 +247,48 @@ struct SkipCacheForType
     bool result = false;
 };
 
+bool Widen::isDirty(TypeId ty)
+{
+    return FFlag::LuauUseCommittingTxnLog ? log->is<SingletonTypeVar>(ty) : bool(get<SingletonTypeVar>(ty));
+}
+
+bool Widen::isDirty(TypePackId)
+{
+    return false;
+}
+
+TypeId Widen::clean(TypeId ty)
+{
+    LUAU_ASSERT(isDirty(ty));
+    auto stv = FFlag::LuauUseCommittingTxnLog ? log->getMutable<SingletonTypeVar>(ty) : getMutable<SingletonTypeVar>(ty);
+    LUAU_ASSERT(stv);
+
+    if (get<StringSingleton>(stv))
+        return getSingletonTypes().stringType;
+    else
+    {
+        // If this assert trips, it's likely we now have number singletons.
+        LUAU_ASSERT(get<BooleanSingleton>(stv));
+        return getSingletonTypes().booleanType;
+    }
+}
+
+TypePackId Widen::clean(TypePackId)
+{
+    throw std::runtime_error("Widen attempted to clean a dirty type pack?");
+}
+
+bool Widen::ignoreChildren(TypeId ty)
+{
+    // Sometimes we unify ("hi") -> free1 with (free2) -> free3, so don't ignore functions.
+    // TODO: should we be doing this? we would need to rework how checkCallOverload does the unification.
+    if (FFlag::LuauUseCommittingTxnLog ? log->is<FunctionTypeVar>(ty) : bool(get<FunctionTypeVar>(ty)))
+        return false;
+
+    // We only care about unions.
+    return !(FFlag::LuauUseCommittingTxnLog ? log->is<UnionTypeVar>(ty) : bool(get<UnionTypeVar>(ty)));
+}
+
 static std::optional<TypeError> hasUnificationTooComplex(const ErrorVec& errors)
 {
     auto isUnificationTooComplex = [](const TypeError& te) {
@@ -263,43 +305,22 @@ static std::optional<TypeError> hasUnificationTooComplex(const ErrorVec& errors)
 // Used for tagged union matching heuristic, returns first singleton type field
 static std::optional<std::pair<Luau::Name, const SingletonTypeVar*>> getTableMatchTag(TypeId type)
 {
-    if (FFlag::LuauUnionTagMatchFix)
+    if (auto ttv = getTableType(type))
     {
-        if (auto ttv = getTableType(type))
+        for (auto&& [name, prop] : ttv->props)
         {
-            for (auto&& [name, prop] : ttv->props)
+            if (auto sing = get<SingletonTypeVar>(follow(prop.type)))
-            {
+                return {{name, sing}};
-                if (auto sing = get<SingletonTypeVar>(follow(prop.type)))
-                    return {{name, sing}};
-            }
-        }
-    }
-    else
-    {
-        type = follow(type);
-
-        if (auto ttv = get<TableTypeVar>(type))
-        {
-            for (auto&& [name, prop] : ttv->props)
-            {
-                if (auto sing = get<SingletonTypeVar>(follow(prop.type)))
-                    return {{name, sing}};
-            }
-        }
-        else if (auto mttv = get<MetatableTypeVar>(type))
-        {
-            return getTableMatchTag(mttv->table);
         }
     }
 
     return std::nullopt;
 }
 
-Unifier::Unifier(TypeArena* types, Mode mode, ScopePtr globalScope, const Location& location, Variance variance, UnifierSharedState& sharedState,
+Unifier::Unifier(TypeArena* types, Mode mode, const Location& location, Variance variance, UnifierSharedState& sharedState,
     TxnLog* parentLog)
     : types(types)
     , mode(mode)
-    , globalScope(std::move(globalScope))
     , log(parentLog)
     , location(location)
     , variance(variance)
@@ -308,11 +329,10 @@ Unifier::Unifier(TypeArena* types, Mode mode, ScopePtr globalScope, const Locati
     LUAU_ASSERT(sharedState.iceHandler);
 }
 
-Unifier::Unifier(TypeArena* types, Mode mode, ScopePtr globalScope, std::vector<std::pair<TypeId, TypeId>>* sharedSeen, const Location& location,
+Unifier::Unifier(TypeArena* types, Mode mode, std::vector<std::pair<TypeId, TypeId>>* sharedSeen, const Location& location,
     Variance variance, UnifierSharedState& sharedState, TxnLog* parentLog)
     : types(types)
     , mode(mode)
-    , globalScope(std::move(globalScope))
     , DEPRECATED_log(sharedSeen)
     , log(parentLog, sharedSeen)
     , location(location)
@@ -435,6 +455,8 @@ void Unifier::tryUnify_(TypeId subTy, TypeId superTy, bool isFunctionCall, bool
     }
     else if (superFree)
     {
+        TypeLevel superLevel = superFree->level;
+
         occursCheck(superTy, subTy);
         bool occursFailed = false;
         if (FFlag::LuauUseCommittingTxnLog)
@@ -442,8 +464,6 @@ void Unifier::tryUnify_(TypeId subTy, TypeId superTy, bool isFunctionCall, bool
         else
             occursFailed = bool(get<ErrorTypeVar>(superTy));
 
-        TypeLevel superLevel = superFree->level;
-
         // Unification can't change the level of a generic.
         auto subGeneric = FFlag::LuauUseCommittingTxnLog ? log.getMutable<GenericTypeVar>(subTy) : get<GenericTypeVar>(subTy);
         if (subGeneric && !subGeneric->level.subsumes(superLevel))
@@ -459,20 +479,14 @@ void Unifier::tryUnify_(TypeId subTy, TypeId superTy, bool isFunctionCall, bool
             if (FFlag::LuauUseCommittingTxnLog)
             {
                 promoteTypeLevels(DEPRECATED_log, log, types, superLevel, subTy);
-                log.replace(superTy, BoundTypeVar(subTy));
+                log.replace(superTy, BoundTypeVar(widen(subTy)));
             }
             else
             {
-                if (FFlag::LuauProperTypeLevels)
+                promoteTypeLevels(DEPRECATED_log, log, types, superLevel, subTy);
-                    promoteTypeLevels(DEPRECATED_log, log, types, superLevel, subTy);
-                else if (auto subLevel = getMutableLevel(subTy))
-                {
-                    if (!subLevel->subsumes(superFree->level))
-                        *subLevel = superFree->level;
-                }
 
                 DEPRECATED_log(superTy);
-                *asMutable(superTy) = BoundTypeVar(subTy);
+                *asMutable(superTy) = BoundTypeVar(widen(subTy));
             }
         }
 
@@ -507,16 +521,7 @@ void Unifier::tryUnify_(TypeId subTy, TypeId superTy, bool isFunctionCall, bool
             }
             else
             {
-                if (FFlag::LuauProperTypeLevels)
+                promoteTypeLevels(DEPRECATED_log, log, types, subLevel, superTy);
-                    promoteTypeLevels(DEPRECATED_log, log, types, subLevel, superTy);
-                else if (auto superLevel = getMutableLevel(superTy))
-                {
-                    if (!superLevel->subsumes(subFree->level))
-                    {
-                        DEPRECATED_log(superTy);
-                        *superLevel = subFree->level;
-                    }
-                }
 
                 DEPRECATED_log(subTy);
                 *asMutable(subTy) = BoundTypeVar(superTy);
@@ -2064,6 +2069,17 @@ void Unifier::tryUnifyTables(TypeId subTy, TypeId superTy, bool isIntersection)
     }
 }
 
+TypeId Unifier::widen(TypeId ty)
+{
+    if (!FFlag::LuauWidenIfSupertypeIsFree)
+        return ty;
+
+    Widen widen{types};
+    std::optional<TypeId> result = widen.substitute(ty);
+    // TODO: what does it mean for substitution to fail to widen?
+    return result.value_or(ty);
+}
+
 TypeId Unifier::deeplyOptional(TypeId ty, std::unordered_map<TypeId, TypeId> seen)
 {
     ty = follow(ty);
@@ -2915,7 +2931,7 @@ void Unifier::tryUnifyWithAny(TypePackId subTy, TypePackId anyTp)
 
 std::optional<TypeId> Unifier::findTablePropertyRespectingMeta(TypeId lhsType, Name name)
 {
-    return Luau::findTablePropertyRespectingMeta(errors, globalScope, lhsType, name, location);
+    return Luau::findTablePropertyRespectingMeta(errors, lhsType, name, location);
 }
 
 void Unifier::occursCheck(TypeId needle, TypeId haystack)
@@ -3096,9 +3112,9 @@ void Unifier::occursCheck(DenseHashSet<TypePackId>& seen, TypePackId needle, Typ
 Unifier Unifier::makeChildUnifier()
 {
     if (FFlag::LuauUseCommittingTxnLog)
-        return Unifier{types, mode, globalScope, log.sharedSeen, location, variance, sharedState, &log};
+        return Unifier{types, mode, log.sharedSeen, location, variance, sharedState, &log};
     else
-        return Unifier{types, mode, globalScope, DEPRECATED_log.sharedSeen, location, variance, sharedState, &log};
+        return Unifier{types, mode, DEPRECATED_log.sharedSeen, location, variance, sharedState, &log};
 }
 
 bool Unifier::isNonstrictMode() const

Ast/src/Parser.cpp

@@ -12,7 +12,6 @@ LUAU_FASTINTVARIABLE(LuauRecursionLimit, 1000)
 LUAU_FASTINTVARIABLE(LuauParseErrorLimit, 100)
 LUAU_FASTFLAGVARIABLE(LuauParseSingletonTypes, false)
 LUAU_FASTFLAGVARIABLE(LuauParseTypeAliasDefaults, false)
-LUAU_FASTFLAGVARIABLE(LuauParseRecoverTypePackEllipsis, false)
 LUAU_FASTFLAGVARIABLE(LuauParseAllHotComments, false)
 LUAU_FASTFLAGVARIABLE(LuauTableFieldFunctionDebugname, false)
 
@@ -2372,11 +2371,11 @@ std::pair<AstArray<AstGenericType>, AstArray<AstGenericTypePack>> Parser::parseG
         {
             Location nameLocation = lexer.current().location;
             AstName name = parseName().name;
-            if (lexer.current().type == Lexeme::Dot3 || (FFlag::LuauParseRecoverTypePackEllipsis && seenPack))
+            if (lexer.current().type == Lexeme::Dot3 || seenPack)
             {
                 seenPack = true;
 
-                if (FFlag::LuauParseRecoverTypePackEllipsis && lexer.current().type != Lexeme::Dot3)
+                if (lexer.current().type != Lexeme::Dot3)
                     report(lexer.current().location, "Generic types come before generic type packs");
                 else
                     nextLexeme();
@@ -2414,9 +2413,6 @@ std::pair<AstArray<AstGenericType>, AstArray<AstGenericTypePack>> Parser::parseG
             }
             else
             {
-                if (!FFlag::LuauParseRecoverTypePackEllipsis && seenPack)
-                    report(lexer.current().location, "Generic types come before generic type packs");
-
                 if (withDefaultValues && lexer.current().type == '=')
                 {
                     seenDefault = true;

VM/include/lua.h

@@ -44,7 +44,7 @@ typedef int (*lua_Continuation)(lua_State* L, int status);
 ** prototype for memory-allocation functions
 */
 
-typedef void* (*lua_Alloc)(lua_State* L, void* ud, void* ptr, size_t osize, size_t nsize);
+typedef void* (*lua_Alloc)(void* ud, void* ptr, size_t osize, size_t nsize);
 
 /* non-return type */
 #define l_noret void LUA_NORETURN
@@ -178,11 +178,11 @@ LUA_API int lua_pushthread(lua_State* L);
 /*
 ** get functions (Lua -> stack)
 */
-LUA_API void lua_gettable(lua_State* L, int idx);
+LUA_API int lua_gettable(lua_State* L, int idx);
-LUA_API void lua_getfield(lua_State* L, int idx, const char* k);
+LUA_API int lua_getfield(lua_State* L, int idx, const char* k);
-LUA_API void lua_rawgetfield(lua_State* L, int idx, const char* k);
+LUA_API int lua_rawgetfield(lua_State* L, int idx, const char* k);
-LUA_API void lua_rawget(lua_State* L, int idx);
+LUA_API int lua_rawget(lua_State* L, int idx);
-LUA_API void lua_rawgeti(lua_State* L, int idx, int n);
+LUA_API int lua_rawgeti(lua_State* L, int idx, int n);
 LUA_API void lua_createtable(lua_State* L, int narr, int nrec);
 
 LUA_API void lua_setreadonly(lua_State* L, int idx, int enabled);

VM/src/lapi.cpp

@@ -659,16 +659,16 @@ int lua_pushthread(lua_State* L)
 ** get functions (Lua -> stack)
 */
 
-void lua_gettable(lua_State* L, int idx)
+int lua_gettable(lua_State* L, int idx)
 {
     luaC_checkthreadsleep(L);
     StkId t = index2addr(L, idx);
     api_checkvalidindex(L, t);
     luaV_gettable(L, t, L->top - 1, L->top - 1);
-    return;
+    return ttype(L->top - 1);
 }
 
-void lua_getfield(lua_State* L, int idx, const char* k)
+int lua_getfield(lua_State* L, int idx, const char* k)
 {
     luaC_checkthreadsleep(L);
     StkId t = index2addr(L, idx);
@@ -677,10 +677,10 @@ void lua_getfield(lua_State* L, int idx, const char* k)
     setsvalue(L, &key, luaS_new(L, k));
     luaV_gettable(L, t, &key, L->top);
     api_incr_top(L);
-    return;
+    return ttype(L->top - 1);
 }
 
-void lua_rawgetfield(lua_State* L, int idx, const char* k)
+int lua_rawgetfield(lua_State* L, int idx, const char* k)
 {
     luaC_checkthreadsleep(L);
     StkId t = index2addr(L, idx);
@@ -689,26 +689,26 @@ void lua_rawgetfield(lua_State* L, int idx, const char* k)
     setsvalue(L, &key, luaS_new(L, k));
     setobj2s(L, L->top, luaH_getstr(hvalue(t), tsvalue(&key)));
     api_incr_top(L);
-    return;
+    return ttype(L->top - 1);
 }
 
-void lua_rawget(lua_State* L, int idx)
+int lua_rawget(lua_State* L, int idx)
 {
     luaC_checkthreadsleep(L);
     StkId t = index2addr(L, idx);
     api_check(L, ttistable(t));
     setobj2s(L, L->top - 1, luaH_get(hvalue(t), L->top - 1));
-    return;
+    return ttype(L->top - 1);
 }
 
-void lua_rawgeti(lua_State* L, int idx, int n)
+int lua_rawgeti(lua_State* L, int idx, int n)
 {
     luaC_checkthreadsleep(L);
     StkId t = index2addr(L, idx);
     api_check(L, ttistable(t));
     setobj2s(L, L->top, luaH_getnum(hvalue(t), n));
     api_incr_top(L);
-    return;
+    return ttype(L->top - 1);
 }
 
 void lua_createtable(lua_State* L, int narray, int nrec)

VM/src/ldo.cpp

@@ -151,8 +151,7 @@ l_noret luaD_throw(lua_State* L, int errcode)
 static void correctstack(lua_State* L, TValue* oldstack)
 {
     L->top = (L->top - oldstack) + L->stack;
-    // TODO (FFlagLuauGcPagedSweep): 'next' type will change after removal of the flag and the cast will not be required
+    for (UpVal* up = L->openupval; up != NULL; up = up->u.l.threadnext)
-    for (UpVal* up = L->openupval; up != NULL; up = (UpVal*)up->next)
         up->v = (up->v - oldstack) + L->stack;
     for (CallInfo* ci = L->base_ci; ci <= L->ci; ci++)
     {

VM/src/lfunc.cpp

@@ -6,13 +6,10 @@
 #include "lmem.h"
 #include "lgc.h"
 
-LUAU_FASTFLAGVARIABLE(LuauNoDirectUpvalRemoval, false)
-LUAU_FASTFLAG(LuauGcPagedSweep)
-
 Proto* luaF_newproto(lua_State* L)
 {
     Proto* f = luaM_newgco(L, Proto, sizeof(Proto), L->activememcat);
-    luaC_link(L, f, LUA_TPROTO);
+    luaC_init(L, f, LUA_TPROTO);
     f->k = NULL;
     f->sizek = 0;
     f->p = NULL;
@@ -40,7 +37,7 @@ Proto* luaF_newproto(lua_State* L)
 Closure* luaF_newLclosure(lua_State* L, int nelems, Table* e, Proto* p)
 {
     Closure* c = luaM_newgco(L, Closure, sizeLclosure(nelems), L->activememcat);
-    luaC_link(L, c, LUA_TFUNCTION);
+    luaC_init(L, c, LUA_TFUNCTION);
     c->isC = 0;
     c->env = e;
     c->nupvalues = cast_byte(nelems);
@@ -55,7 +52,7 @@ Closure* luaF_newLclosure(lua_State* L, int nelems, Table* e, Proto* p)
 Closure* luaF_newCclosure(lua_State* L, int nelems, Table* e)
 {
     Closure* c = luaM_newgco(L, Closure, sizeCclosure(nelems), L->activememcat);
-    luaC_link(L, c, LUA_TFUNCTION);
+    luaC_init(L, c, LUA_TFUNCTION);
     c->isC = 1;
     c->env = e;
     c->nupvalues = cast_byte(nelems);
@@ -82,8 +79,7 @@ UpVal* luaF_findupval(lua_State* L, StkId level)
             return p;
         }
 
-        // TODO (FFlagLuauGcPagedSweep): 'next' type will change after removal of the flag and the cast will not be required
+        pp = &p->u.l.threadnext;
-        pp = (UpVal**)&p->next;
     }
 
     UpVal* uv = luaM_newgco(L, UpVal, sizeof(UpVal), L->activememcat); /* not found: create a new one */
@@ -94,19 +90,10 @@ UpVal* luaF_findupval(lua_State* L, StkId level)
 
     // chain the upvalue in the threads open upvalue list at the proper position
     UpVal* next = *pp;
-
+    uv->u.l.threadnext = next;
-    // TODO (FFlagLuauGcPagedSweep): 'next' type will change after removal of the flag and the cast will not be required
+    uv->u.l.threadprev = pp;
-    uv->next = (GCObject*)next;
+    if (next)
-
+        next->u.l.threadprev = &uv->u.l.threadnext;
-    if (FFlag::LuauGcPagedSweep)
-    {
-        uv->u.l.threadprev = pp;
-        if (next)
-        {
-            // TODO (FFlagLuauGcPagedSweep): 'next' type will change after removal of the flag and the cast will not be required
-            next->u.l.threadprev = (UpVal**)&uv->next;
-        }
-    }
 
     *pp = uv;
 
@@ -125,15 +112,11 @@ void luaF_unlinkupval(UpVal* uv)
     uv->u.l.next->u.l.prev = uv->u.l.prev;
     uv->u.l.prev->u.l.next = uv->u.l.next;
 
-    if (FFlag::LuauGcPagedSweep)
+    // unlink upvalue from the thread open upvalue list
-    {
+    *uv->u.l.threadprev = uv->u.l.threadnext;
-        // unlink upvalue from the thread open upvalue list
-        // TODO (FFlagLuauGcPagedSweep): 'next' type will change after removal of the flag and this and the following cast will not be required
-        *uv->u.l.threadprev = (UpVal*)uv->next;
 
-        if (UpVal* next = (UpVal*)uv->next)
+    if (UpVal* next = uv->u.l.threadnext)
-            next->u.l.threadprev = uv->u.l.threadprev;
+        next->u.l.threadprev = uv->u.l.threadprev;
-    }
 }
 
 void luaF_freeupval(lua_State* L, UpVal* uv, lua_Page* page)
@@ -145,34 +128,27 @@ void luaF_freeupval(lua_State* L, UpVal* uv, lua_Page* page)
 
 void luaF_close(lua_State* L, StkId level)
 {
-    global_State* g = L->global; // TODO: remove with FFlagLuauNoDirectUpvalRemoval
+    global_State* g = L->global;
     UpVal* uv;
     while (L->openupval != NULL && (uv = L->openupval)->v >= level)
     {
         GCObject* o = obj2gco(uv);
         LUAU_ASSERT(!isblack(o) && uv->v != &uv->u.value);
 
-        if (!FFlag::LuauGcPagedSweep)
+        // by removing the upvalue from global/thread open upvalue lists, L->openupval will be pointing to the next upvalue
-            L->openupval = (UpVal*)uv->next; /* remove from `open' list */
+        luaF_unlinkupval(uv);
 
-        if (FFlag::LuauGcPagedSweep && isdead(g, o))
+        if (isdead(g, o))
         {
-            // by removing the upvalue from global/thread open upvalue lists, L->openupval will be pointing to the next upvalue
-            luaF_unlinkupval(uv);
             // close the upvalue without copying the dead data so that luaF_freeupval will not unlink again
             uv->v = &uv->u.value;
         }
-        else if (!FFlag::LuauNoDirectUpvalRemoval && isdead(g, o))
-        {
-            luaF_freeupval(L, uv, NULL); /* free upvalue */
-        }
         else
         {
-            // by removing the upvalue from global/thread open upvalue lists, L->openupval will be pointing to the next upvalue
-            luaF_unlinkupval(uv);
             setobj(L, &uv->u.value, uv->v);
-            uv->v = &uv->u.value;  /* now current value lives here */
+            uv->v = &uv->u.value;
-            luaC_linkupval(L, uv); /* link upvalue into `gcroot' list */
+            // GC state of a new closed upvalue has to be initialized
+            luaC_initupval(L, uv);
         }
     }
 }

VM/src/lgc.cpp

@@ -13,8 +13,6 @@
 
 #include <string.h>
 
-LUAU_FASTFLAGVARIABLE(LuauGcPagedSweep, false)
-
 #define GC_SWEEPMAX 40
 #define GC_SWEEPCOST 10
 #define GC_SWEEPPAGESTEPCOST 4
@@ -64,7 +62,6 @@ static void recordGcStateTime(global_State* g, int startgcstate, double seconds,
     case GCSatomic:
         g->gcstats.currcycle.atomictime += seconds;
         break;
-    case GCSsweepstring:
     case GCSsweep:
         g->gcstats.currcycle.sweeptime += seconds;
         break;
@@ -490,65 +487,6 @@ static void freeobj(lua_State* L, GCObject* o, lua_Page* page)
     }
 }
 
-#define sweepwholelist(L, p) sweeplist(L, p, SIZE_MAX)
-
-static GCObject** sweeplist(lua_State* L, GCObject** p, size_t count)
-{
-    LUAU_ASSERT(!FFlag::LuauGcPagedSweep);
-
-    GCObject* curr;
-    global_State* g = L->global;
-    int deadmask = otherwhite(g);
-    LUAU_ASSERT(testbit(deadmask, FIXEDBIT)); /* make sure we never sweep fixed objects */
-    while ((curr = *p) != NULL && count-- > 0)
-    {
-        int alive = (curr->gch.marked ^ WHITEBITS) & deadmask;
-        if (curr->gch.tt == LUA_TTHREAD)
-        {
-            sweepwholelist(L, (GCObject**)&gco2th(curr)->openupval); /* sweep open upvalues */
-
-            lua_State* th = gco2th(curr);
-
-            if (alive)
-            {
-                resetbit(th->stackstate, THREAD_SLEEPINGBIT);
-                shrinkstack(th);
-            }
-        }
-        if (alive)
-        { /* not dead? */
-            LUAU_ASSERT(!isdead(g, curr));
-            makewhite(g, curr); /* make it white (for next cycle) */
-            p = &curr->gch.next;
-        }
-        else
-        { /* must erase `curr' */
-            LUAU_ASSERT(isdead(g, curr));
-            *p = curr->gch.next;
-            if (curr == g->rootgc)          /* is the first element of the list? */
-                g->rootgc = curr->gch.next; /* adjust first */
-            freeobj(L, curr, NULL);
-        }
-    }
-
-    return p;
-}
-
-static void deletelist(lua_State* L, GCObject** p, GCObject* limit)
-{
-    LUAU_ASSERT(!FFlag::LuauGcPagedSweep);
-
-    GCObject* curr;
-    while ((curr = *p) != limit)
-    {
-        if (curr->gch.tt == LUA_TTHREAD) /* delete open upvalues of each thread */
-            deletelist(L, (GCObject**)&gco2th(curr)->openupval, NULL);
-
-        *p = curr->gch.next;
-        freeobj(L, curr, NULL);
-    }
-}
-
 static void shrinkbuffers(lua_State* L)
 {
     global_State* g = L->global;
@@ -570,8 +508,6 @@ static void shrinkbuffersfull(lua_State* L)
 
 static bool deletegco(void* context, lua_Page* page, GCObject* gco)
 {
-    LUAU_ASSERT(FFlag::LuauGcPagedSweep);
-
     // we are in the process of deleting everything
     // threads with open upvalues will attempt to close them all on removal
     // but those upvalues might point to stack values that were already deleted
@@ -598,32 +534,13 @@ void luaC_freeall(lua_State* L)
 
     LUAU_ASSERT(L == g->mainthread);
 
-    if (FFlag::LuauGcPagedSweep)
+    luaM_visitgco(L, L, deletegco);
-    {
-        luaM_visitgco(L, L, deletegco);
 
-        for (int i = 0; i < g->strt.size; i++) /* free all string lists */
+    for (int i = 0; i < g->strt.size; i++) /* free all string lists */
-            LUAU_ASSERT(g->strt.hash[i] == NULL);
+        LUAU_ASSERT(g->strt.hash[i] == NULL);
 
-        LUAU_ASSERT(L->global->strt.nuse == 0);
+    LUAU_ASSERT(L->global->strt.nuse == 0);
-        LUAU_ASSERT(g->strbufgc == NULL);
+    LUAU_ASSERT(g->strbufgc == NULL);
-    }
-    else
-    {
-        LUAU_ASSERT(L->next == NULL); /* mainthread is at the end of rootgc list */
-
-        deletelist(L, &g->rootgc, obj2gco(L));
-
-        for (int i = 0; i < g->strt.size; i++) /* free all string lists */
-            deletelist(L, (GCObject**)&g->strt.hash[i], NULL);
-
-        LUAU_ASSERT(L->global->strt.nuse == 0);
-        deletelist(L, (GCObject**)&g->strbufgc, NULL);
-
-        // unfortunately, when string objects are freed, the string table use count is decremented
-        // even when the string is a buffer that wasn't placed into the table
-        L->global->strt.nuse = 0;
-    }
 }
 
 static void markmt(global_State* g)
@@ -687,26 +604,13 @@ static size_t atomic(lua_State* L)
     g->weak = NULL;
     /* flip current white */
     g->currentwhite = cast_byte(otherwhite(g));
-    g->sweepstrgc = 0;
+    g->sweepgcopage = g->allgcopages;
-
+    g->gcstate = GCSsweep;
-    if (FFlag::LuauGcPagedSweep)
-    {
-        g->sweepgcopage = g->allgcopages;
-        g->gcstate = GCSsweep;
-    }
-    else
-    {
-        g->sweepgc = &g->rootgc;
-        g->gcstate = GCSsweepstring;
-    }
-
     return work;
 }
 
 static bool sweepgco(lua_State* L, lua_Page* page, GCObject* gco)
 {
-    LUAU_ASSERT(FFlag::LuauGcPagedSweep);
-
     global_State* g = L->global;
 
     int deadmask = otherwhite(g);
@@ -740,8 +644,6 @@ static bool sweepgco(lua_State* L, lua_Page* page, GCObject* gco)
 // a version of generic luaM_visitpage specialized for the main sweep stage
 static int sweepgcopage(lua_State* L, lua_Page* page)
 {
-    LUAU_ASSERT(FFlag::LuauGcPagedSweep);
-
     char* start;
     char* end;
     int busyBlocks;
@@ -819,75 +721,29 @@ static size_t gcstep(lua_State* L, size_t limit)
 
         cost = atomic(L); /* finish mark phase */
 
-        if (FFlag::LuauGcPagedSweep)
+        LUAU_ASSERT(g->gcstate == GCSsweep);
-            LUAU_ASSERT(g->gcstate == GCSsweep);
-        else
-            LUAU_ASSERT(g->gcstate == GCSsweepstring);
-        break;
-    }
-    case GCSsweepstring:
-    {
-        LUAU_ASSERT(!FFlag::LuauGcPagedSweep);
-
-        while (g->sweepstrgc < g->strt.size && cost < limit)
-        {
-            sweepwholelist(L, (GCObject**)&g->strt.hash[g->sweepstrgc++]);
-
-            cost += GC_SWEEPCOST;
-        }
-
-        // nothing more to sweep?
-        if (g->sweepstrgc >= g->strt.size)
-        {
-            // sweep string buffer list and preserve used string count
-            uint32_t nuse = L->global->strt.nuse;
-
-            sweepwholelist(L, (GCObject**)&g->strbufgc);
-
-            L->global->strt.nuse = nuse;
-
-            g->gcstate = GCSsweep; // end sweep-string phase
-        }
         break;
     }
     case GCSsweep:
     {
-        if (FFlag::LuauGcPagedSweep)
+        while (g->sweepgcopage && cost < limit)
         {
-            while (g->sweepgcopage && cost < limit)
+            lua_Page* next = luaM_getnextgcopage(g->sweepgcopage); // page sweep might destroy the page
-            {
-                lua_Page* next = luaM_getnextgcopage(g->sweepgcopage); // page sweep might destroy the page
 
-                int steps = sweepgcopage(L, g->sweepgcopage);
+            int steps = sweepgcopage(L, g->sweepgcopage);
 
-                g->sweepgcopage = next;
+            g->sweepgcopage = next;
-                cost += steps * GC_SWEEPPAGESTEPCOST;
+            cost += steps * GC_SWEEPPAGESTEPCOST;
-            }
-
-            // nothing more to sweep?
-            if (g->sweepgcopage == NULL)
-            {
-                // don't forget to visit main thread
-                sweepgco(L, NULL, obj2gco(g->mainthread));
-
-                shrinkbuffers(L);
-                g->gcstate = GCSpause; /* end collection */
-            }
         }
-        else
+
+        // nothing more to sweep?
+        if (g->sweepgcopage == NULL)
         {
-            while (*g->sweepgc && cost < limit)
+            // don't forget to visit main thread
-            {
+            sweepgco(L, NULL, obj2gco(g->mainthread));
-                g->sweepgc = sweeplist(L, g->sweepgc, GC_SWEEPMAX);
 
-                cost += GC_SWEEPMAX * GC_SWEEPCOST;
+            shrinkbuffers(L);
-            }
+            g->gcstate = GCSpause; /* end collection */
-
-            if (*g->sweepgc == NULL)
-            { /* nothing more to sweep? */
-                shrinkbuffers(L);
-                g->gcstate = GCSpause; /* end collection */
-            }
         }
         break;
     }
@@ -1013,26 +869,18 @@ void luaC_fullgc(lua_State* L)
     if (g->gcstate <= GCSatomic)
     {
         /* reset sweep marks to sweep all elements (returning them to white) */
-        g->sweepstrgc = 0;
+        g->sweepgcopage = g->allgcopages;
-        if (FFlag::LuauGcPagedSweep)
-            g->sweepgcopage = g->allgcopages;
-        else
-            g->sweepgc = &g->rootgc;
         /* reset other collector lists */
         g->gray = NULL;
         g->grayagain = NULL;
         g->weak = NULL;
-
+        g->gcstate = GCSsweep;
-        if (FFlag::LuauGcPagedSweep)
-            g->gcstate = GCSsweep;
-        else
-            g->gcstate = GCSsweepstring;
     }
-    LUAU_ASSERT(g->gcstate == GCSsweepstring || g->gcstate == GCSsweep);
+    LUAU_ASSERT(g->gcstate == GCSsweep);
     /* finish any pending sweep phase */
     while (g->gcstate != GCSpause)
     {
-        LUAU_ASSERT(g->gcstate == GCSsweepstring || g->gcstate == GCSsweep);
+        LUAU_ASSERT(g->gcstate == GCSsweep);
         gcstep(L, SIZE_MAX);
     }
 
@@ -1120,30 +968,19 @@ void luaC_barrierback(lua_State* L, Table* t)
     g->grayagain = o;
 }
 
-void luaC_linkobj(lua_State* L, GCObject* o, uint8_t tt)
+void luaC_initobj(lua_State* L, GCObject* o, uint8_t tt)
 {
     global_State* g = L->global;
-    if (!FFlag::LuauGcPagedSweep)
-    {
-        o->gch.next = g->rootgc;
-        g->rootgc = o;
-    }
     o->gch.marked = luaC_white(g);
     o->gch.tt = tt;
     o->gch.memcat = L->activememcat;
 }
 
-void luaC_linkupval(lua_State* L, UpVal* uv)
+void luaC_initupval(lua_State* L, UpVal* uv)
 {
     global_State* g = L->global;
     GCObject* o = obj2gco(uv);
 
-    if (!FFlag::LuauGcPagedSweep)
-    {
-        o->gch.next = g->rootgc; /* link upvalue into `rootgc' list */
-        g->rootgc = o;
-    }
-
     if (isgray(o))
     {
         if (keepinvariant(g))
@@ -1221,9 +1058,6 @@ const char* luaC_statename(int state)
     case GCSatomic:
         return "atomic";
 
-    case GCSsweepstring:
-        return "sweepstring";
-
     case GCSsweep:
         return "sweep";
 

VM/src/lgc.h

@@ -13,9 +13,7 @@
 #define GCSpropagate 1
 #define GCSpropagateagain 2
 #define GCSatomic 3
-// TODO: remove with FFlagLuauGcPagedSweep
+#define GCSsweep 4
-#define GCSsweepstring 4
-#define GCSsweep 5
 
 /*
 ** macro to tell when main invariant (white objects cannot point to black
@@ -132,13 +130,13 @@
             luaC_wakethread(L); \
     }
 
-#define luaC_link(L, o, tt) luaC_linkobj(L, cast_to(GCObject*, (o)), tt)
+#define luaC_init(L, o, tt) luaC_initobj(L, cast_to(GCObject*, (o)), tt)
 
 LUAI_FUNC void luaC_freeall(lua_State* L);
 LUAI_FUNC void luaC_step(lua_State* L, bool assist);
 LUAI_FUNC void luaC_fullgc(lua_State* L);
-LUAI_FUNC void luaC_linkobj(lua_State* L, GCObject* o, uint8_t tt);
+LUAI_FUNC void luaC_initobj(lua_State* L, GCObject* o, uint8_t tt);
-LUAI_FUNC void luaC_linkupval(lua_State* L, UpVal* uv);
+LUAI_FUNC void luaC_initupval(lua_State* L, UpVal* uv);
 LUAI_FUNC void luaC_barrierupval(lua_State* L, GCObject* v);
 LUAI_FUNC void luaC_barrierf(lua_State* L, GCObject* o, GCObject* v);
 LUAI_FUNC void luaC_barriertable(lua_State* L, Table* t, GCObject* v);

VM/src/lgcdebug.cpp

@@ -13,8 +13,6 @@
 #include <string.h>
 #include <stdio.h>
 
-LUAU_FASTFLAG(LuauGcPagedSweep)
-
 static void validateobjref(global_State* g, GCObject* f, GCObject* t)
 {
     LUAU_ASSERT(!isdead(g, t));
@@ -104,8 +102,7 @@ static void validatestack(global_State* g, lua_State* l)
     if (l->namecall)
         validateobjref(g, obj2gco(l), obj2gco(l->namecall));
 
-    // TODO (FFlagLuauGcPagedSweep): 'next' type will change after removal of the flag and the cast will not be required
+    for (UpVal* uv = l->openupval; uv; uv = uv->u.l.threadnext)
-    for (UpVal* uv = l->openupval; uv; uv = (UpVal*)uv->next)
     {
         LUAU_ASSERT(uv->tt == LUA_TUPVAL);
         LUAU_ASSERT(uv->v != &uv->u.value);
@@ -141,7 +138,7 @@ static void validateobj(global_State* g, GCObject* o)
     /* dead objects can only occur during sweep */
     if (isdead(g, o))
     {
-        LUAU_ASSERT(g->gcstate == GCSsweepstring || g->gcstate == GCSsweep);
+        LUAU_ASSERT(g->gcstate == GCSsweep);
         return;
     }
 
@@ -180,18 +177,6 @@ static void validateobj(global_State* g, GCObject* o)
     }
 }
 
-static void validatelist(global_State* g, GCObject* o)
-{
-    LUAU_ASSERT(!FFlag::LuauGcPagedSweep);
-
-    while (o)
-    {
-        validateobj(g, o);
-
-        o = o->gch.next;
-    }
-}
-
 static void validategraylist(global_State* g, GCObject* o)
 {
     if (!keepinvariant(g))
@@ -224,8 +209,6 @@ static void validategraylist(global_State* g, GCObject* o)
 
 static bool validategco(void* context, lua_Page* page, GCObject* gco)
 {
-    LUAU_ASSERT(FFlag::LuauGcPagedSweep);
-
     lua_State* L = (lua_State*)context;
     global_State* g = L->global;
 
@@ -248,20 +231,9 @@ void luaC_validate(lua_State* L)
     validategraylist(g, g->gray);
     validategraylist(g, g->grayagain);
 
-    if (FFlag::LuauGcPagedSweep)
+    validategco(L, NULL, obj2gco(g->mainthread));
-    {
-        validategco(L, NULL, obj2gco(g->mainthread));
 
-        luaM_visitgco(L, L, validategco);
+    luaM_visitgco(L, L, validategco);
-    }
-    else
-    {
-        for (int i = 0; i < g->strt.size; ++i)
-            validatelist(g, (GCObject*)(g->strt.hash[i]));
-
-        validatelist(g, g->rootgc);
-        validatelist(g, (GCObject*)(g->strbufgc));
-    }
 
     for (UpVal* uv = g->uvhead.u.l.next; uv != &g->uvhead; uv = uv->u.l.next)
     {
@@ -521,30 +493,8 @@ static void dumpobj(FILE* f, GCObject* o)
     }
 }
 
-static void dumplist(FILE* f, GCObject* o)
-{
-    LUAU_ASSERT(!FFlag::LuauGcPagedSweep);
-
-    while (o)
-    {
-        dumpref(f, o);
-        fputc(':', f);
-        dumpobj(f, o);
-        fputc(',', f);
-        fputc('\n', f);
-
-        // thread has additional list containing collectable objects that are not present in rootgc
-        if (o->gch.tt == LUA_TTHREAD)
-            dumplist(f, (GCObject*)gco2th(o)->openupval);
-
-        o = o->gch.next;
-    }
-}
-
 static bool dumpgco(void* context, lua_Page* page, GCObject* gco)
 {
-    LUAU_ASSERT(FFlag::LuauGcPagedSweep);
-
     FILE* f = (FILE*)context;
 
     dumpref(f, gco);
@@ -563,19 +513,9 @@ void luaC_dump(lua_State* L, void* file, const char* (*categoryName)(lua_State*
 
     fprintf(f, "{\"objects\":{\n");
 
-    if (FFlag::LuauGcPagedSweep)
+    dumpgco(f, NULL, obj2gco(g->mainthread));
-    {
-        dumpgco(f, NULL, obj2gco(g->mainthread));
 
-        luaM_visitgco(L, f, dumpgco);
+    luaM_visitgco(L, f, dumpgco);
-    }
-    else
-    {
-        dumplist(f, g->rootgc);
-        dumplist(f, (GCObject*)(g->strbufgc));
-        for (int i = 0; i < g->strt.size; ++i)
-            dumplist(f, (GCObject*)(g->strt.hash[i]));
-    }
 
     fprintf(f, "\"0\":{\"type\":\"userdata\",\"cat\":0,\"size\":0}\n"); // to avoid issues with trailing ,
     fprintf(f, "},\"roots\":{\n");

VM/src/linit.cpp

@@ -68,7 +68,7 @@ void luaL_sandboxthread(lua_State* L)
     lua_setsafeenv(L, LUA_GLOBALSINDEX, true);
 }
 
-static void* l_alloc(lua_State* L, void* ud, void* ptr, size_t osize, size_t nsize)
+static void* l_alloc(void* ud, void* ptr, size_t osize, size_t nsize)
 {
     (void)ud;
     (void)osize;

VM/src/lmem.cpp

@@ -78,8 +78,6 @@
  * allocated pages.
  */
 
-LUAU_FASTFLAG(LuauGcPagedSweep)
-
 #ifndef __has_feature
 #define __has_feature(x) 0
 #endif
@@ -98,8 +96,10 @@ LUAU_FASTFLAG(LuauGcPagedSweep)
  * To prevent some of them accidentally growing and us losing memory without realizing it, we're going to lock
  * the sizes of all critical structures down.
  */
-#if defined(__APPLE__) && !defined(__MACH__)
+#if defined(__APPLE__)
 #define ABISWITCH(x64, ms32, gcc32) (sizeof(void*) == 8 ? x64 : gcc32)
+#elif defined(__i386__)
+#define ABISWITCH(x64, ms32, gcc32) (gcc32)
 #else
 // Android somehow uses a similar ABI to MSVC, *not* to iOS...
 #define ABISWITCH(x64, ms32, gcc32) (sizeof(void*) == 8 ? x64 : ms32)
@@ -114,14 +114,8 @@ static_assert(sizeof(LuaNode) == ABISWITCH(32, 32, 32), "size mismatch for table
 #endif
 
 static_assert(offsetof(TString, data) == ABISWITCH(24, 20, 20), "size mismatch for string header");
-// TODO (FFlagLuauGcPagedSweep): this will become ABISWITCH(16, 16, 16)
+static_assert(offsetof(Udata, data) == ABISWITCH(16, 16, 12), "size mismatch for userdata header");
-static_assert(offsetof(Udata, data) == ABISWITCH(24, 16, 16), "size mismatch for userdata header");
+static_assert(sizeof(Table) == ABISWITCH(48, 32, 32), "size mismatch for table header");
-// TODO (FFlagLuauGcPagedSweep): this will become ABISWITCH(48, 32, 32)
-static_assert(sizeof(Table) == ABISWITCH(56, 36, 36), "size mismatch for table header");
-
-// TODO (FFlagLuauGcPagedSweep): new code with old 'next' pointer requires that GCObject start at the same point as TString/UpVal
-static_assert(offsetof(GCObject, uv) == 0, "UpVal data must be located at the start of the GCObject");
-static_assert(offsetof(GCObject, ts) == 0, "TString data must be located at the start of the GCObject");
 
 const size_t kSizeClasses = LUA_SIZECLASSES;
 const size_t kMaxSmallSize = 512;
@@ -208,53 +202,13 @@ l_noret luaM_toobig(lua_State* L)
     luaG_runerror(L, "memory allocation error: block too big");
 }
 
-static lua_Page* newpageold(lua_State* L, uint8_t sizeClass)
-{
-    LUAU_ASSERT(!FFlag::LuauGcPagedSweep);
-
-    global_State* g = L->global;
-    lua_Page* page = (lua_Page*)(*g->frealloc)(L, g->ud, NULL, 0, kPageSize);
-    if (!page)
-        luaD_throw(L, LUA_ERRMEM);
-
-    int blockSize = kSizeClassConfig.sizeOfClass[sizeClass] + kBlockHeader;
-    int blockCount = (kPageSize - offsetof(lua_Page, data)) / blockSize;
-
-    ASAN_POISON_MEMORY_REGION(page->data, blockSize * blockCount);
-
-    // setup page header
-    page->prev = NULL;
-    page->next = NULL;
-
-    page->gcolistprev = NULL;
-    page->gcolistnext = NULL;
-
-    page->pageSize = kPageSize;
-    page->blockSize = blockSize;
-
-    // note: we start with the last block in the page and move downward
-    // either order would work, but that way we don't need to store the block count in the page
-    // additionally, GC stores objects in singly linked lists, and this way the GC lists end up in increasing pointer order
-    page->freeList = NULL;
-    page->freeNext = (blockCount - 1) * blockSize;
-    page->busyBlocks = 0;
-
-    // prepend a page to page freelist (which is empty because we only ever allocate a new page when it is!)
-    LUAU_ASSERT(!g->freepages[sizeClass]);
-    g->freepages[sizeClass] = page;
-
-    return page;
-}
-
 static lua_Page* newpage(lua_State* L, lua_Page** gcopageset, int pageSize, int blockSize, int blockCount)
 {
-    LUAU_ASSERT(FFlag::LuauGcPagedSweep);
-
     global_State* g = L->global;
 
     LUAU_ASSERT(pageSize - int(offsetof(lua_Page, data)) >= blockSize * blockCount);
 
-    lua_Page* page = (lua_Page*)(*g->frealloc)(L, g->ud, NULL, 0, pageSize);
+    lua_Page* page = (lua_Page*)(*g->frealloc)(g->ud, NULL, 0, pageSize);
     if (!page)
         luaD_throw(L, LUA_ERRMEM);
 
@@ -290,8 +244,6 @@ static lua_Page* newpage(lua_State* L, lua_Page** gcopageset, int pageSize, int
 
 static lua_Page* newclasspage(lua_State* L, lua_Page** freepageset, lua_Page** gcopageset, uint8_t sizeClass, bool storeMetadata)
 {
-    LUAU_ASSERT(FFlag::LuauGcPagedSweep);
-
     int blockSize = kSizeClassConfig.sizeOfClass[sizeClass] + (storeMetadata ? kBlockHeader : 0);
     int blockCount = (kPageSize - offsetof(lua_Page, data)) / blockSize;
 
@@ -304,29 +256,8 @@ static lua_Page* newclasspage(lua_State* L, lua_Page** freepageset, lua_Page** g
     return page;
 }
 
-static void freepageold(lua_State* L, lua_Page* page, uint8_t sizeClass)
-{
-    LUAU_ASSERT(!FFlag::LuauGcPagedSweep);
-
-    global_State* g = L->global;
-
-    // remove page from freelist
-    if (page->next)
-        page->next->prev = page->prev;
-
-    if (page->prev)
-        page->prev->next = page->next;
-    else if (g->freepages[sizeClass] == page)
-        g->freepages[sizeClass] = page->next;
-
-    // so long
-    (*g->frealloc)(L, g->ud, page, kPageSize, 0);
-}
-
 static void freepage(lua_State* L, lua_Page** gcopageset, lua_Page* page)
 {
-    LUAU_ASSERT(FFlag::LuauGcPagedSweep);
-
     global_State* g = L->global;
 
     if (gcopageset)
@@ -342,13 +273,11 @@ static void freepage(lua_State* L, lua_Page** gcopageset, lua_Page* page)
     }
 
     // so long
-    (*g->frealloc)(L, g->ud, page, page->pageSize, 0);
+    (*g->frealloc)(g->ud, page, page->pageSize, 0);
 }
 
 static void freeclasspage(lua_State* L, lua_Page** freepageset, lua_Page** gcopageset, lua_Page* page, uint8_t sizeClass)
 {
-    LUAU_ASSERT(FFlag::LuauGcPagedSweep);
-
     // remove page from freelist
     if (page->next)
         page->next->prev = page->prev;
@@ -368,12 +297,7 @@ 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);
-        if (FFlag::LuauGcPagedSweep)
-            page = newclasspage(L, g->freepages, NULL, sizeClass, true);
-        else
-            page = newpageold(L, sizeClass);
-    }
 
     LUAU_ASSERT(!page->prev);
     LUAU_ASSERT(page->freeList || page->freeNext >= 0);
@@ -416,8 +340,6 @@ static void* newblock(lua_State* L, int sizeClass)
 
 static void* newgcoblock(lua_State* L, int sizeClass)
 {
-    LUAU_ASSERT(FFlag::LuauGcPagedSweep);
-
     global_State* g = L->global;
     lua_Page* page = g->freegcopages[sizeClass];
 
@@ -496,17 +418,11 @@ 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);
-        if (FFlag::LuauGcPagedSweep)
-            freeclasspage(L, g->freepages, NULL, page, sizeClass);
-        else
-            freepageold(L, page, sizeClass);
-    }
 }
 
 static void freegcoblock(lua_State* L, int sizeClass, void* block, lua_Page* page)
 {
-    LUAU_ASSERT(FFlag::LuauGcPagedSweep);
     LUAU_ASSERT(page && page->busyBlocks > 0);
     LUAU_ASSERT(page->blockSize == kSizeClassConfig.sizeOfClass[sizeClass]);
     LUAU_ASSERT(block >= page->data && block < (char*)page + page->pageSize);
@@ -544,7 +460,7 @@ void* luaM_new_(lua_State* L, size_t nsize, uint8_t memcat)
 
     int nclass = sizeclass(nsize);
 
-    void* block = nclass >= 0 ? newblock(L, nclass) : (*g->frealloc)(L, g->ud, NULL, 0, nsize);
+    void* block = nclass >= 0 ? newblock(L, nclass) : (*g->frealloc)(g->ud, NULL, 0, nsize);
     if (block == NULL && nsize > 0)
         luaD_throw(L, LUA_ERRMEM);
 
@@ -556,9 +472,6 @@ void* luaM_new_(lua_State* L, size_t nsize, uint8_t memcat)
 
 GCObject* luaM_newgco_(lua_State* L, size_t nsize, uint8_t memcat)
 {
-    if (!FFlag::LuauGcPagedSweep)
-        return (GCObject*)luaM_new_(L, nsize, memcat);
-
     // we need to accommodate space for link for free blocks (freegcolink)
     LUAU_ASSERT(nsize >= kGCOLinkOffset + sizeof(void*));
 
@@ -602,7 +515,7 @@ void luaM_free_(lua_State* L, void* block, size_t osize, uint8_t memcat)
     if (oclass >= 0)
         freeblock(L, oclass, block);
     else
-        (*g->frealloc)(L, g->ud, block, osize, 0);
+        (*g->frealloc)(g->ud, block, osize, 0);
 
     g->totalbytes -= osize;
     g->memcatbytes[memcat] -= osize;
@@ -610,12 +523,6 @@ void luaM_free_(lua_State* L, void* block, size_t osize, uint8_t memcat)
 
 void luaM_freegco_(lua_State* L, GCObject* block, size_t osize, uint8_t memcat, lua_Page* page)
 {
-    if (!FFlag::LuauGcPagedSweep)
-    {
-        luaM_free_(L, block, osize, memcat);
-        return;
-    }
-
     global_State* g = L->global;
     LUAU_ASSERT((osize == 0) == (block == NULL));
 
@@ -652,7 +559,7 @@ void* luaM_realloc_(lua_State* L, void* block, size_t osize, size_t nsize, uint8
     // if either block needs to be allocated using a block allocator, we can't use realloc directly
     if (nclass >= 0 || oclass >= 0)
     {
-        result = nclass >= 0 ? newblock(L, nclass) : (*g->frealloc)(L, g->ud, NULL, 0, nsize);
+        result = nclass >= 0 ? newblock(L, nclass) : (*g->frealloc)(g->ud, NULL, 0, nsize);
         if (result == NULL && nsize > 0)
             luaD_throw(L, LUA_ERRMEM);
 
@@ -662,11 +569,11 @@ void* luaM_realloc_(lua_State* L, void* block, size_t osize, size_t nsize, uint8
         if (oclass >= 0)
             freeblock(L, oclass, block);
         else
-            (*g->frealloc)(L, g->ud, block, osize, 0);
+            (*g->frealloc)(g->ud, block, osize, 0);
     }
     else
     {
-        result = (*g->frealloc)(L, g->ud, block, osize, nsize);
+        result = (*g->frealloc)(g->ud, block, osize, nsize);
         if (result == NULL && nsize > 0)
             luaD_throw(L, LUA_ERRMEM);
     }
@@ -679,8 +586,6 @@ void* luaM_realloc_(lua_State* L, void* block, size_t osize, size_t nsize, uint8
 
 void luaM_getpagewalkinfo(lua_Page* page, char** start, char** end, int* busyBlocks, int* blockSize)
 {
-    LUAU_ASSERT(FFlag::LuauGcPagedSweep);
-
     int blockCount = (page->pageSize - offsetof(lua_Page, data)) / page->blockSize;
 
     LUAU_ASSERT(page->freeNext >= -page->blockSize && page->freeNext <= (blockCount - 1) * page->blockSize);
@@ -700,8 +605,6 @@ lua_Page* luaM_getnextgcopage(lua_Page* page)
 
 void luaM_visitpage(lua_Page* page, void* context, bool (*visitor)(void* context, lua_Page* page, GCObject* gco))
 {
-    LUAU_ASSERT(FFlag::LuauGcPagedSweep);
-
     char* start;
     char* end;
     int busyBlocks;
@@ -730,8 +633,6 @@ void luaM_visitpage(lua_Page* page, void* context, bool (*visitor)(void* context
 
 void luaM_visitgco(lua_State* L, void* context, bool (*visitor)(void* context, lua_Page* page, GCObject* gco))
 {
-    LUAU_ASSERT(FFlag::LuauGcPagedSweep);
-
     global_State* g = L->global;
 
     for (lua_Page* curr = g->allgcopages; curr;)

VM/src/lmem.h

@@ -7,11 +7,7 @@
 struct lua_Page;
 union GCObject;
 
-// TODO: remove with FFlagLuauGcPagedSweep and rename luaM_newgco to luaM_new
-#define luaM_new(L, t, size, memcat) cast_to(t*, luaM_new_(L, size, memcat))
 #define luaM_newgco(L, t, size, memcat) cast_to(t*, luaM_newgco_(L, size, memcat))
-// TODO: remove with FFlagLuauGcPagedSweep and rename luaM_freegco to luaM_free
-#define luaM_free(L, p, size, memcat) luaM_free_(L, (p), size, memcat)
 #define luaM_freegco(L, p, size, memcat, page) luaM_freegco_(L, obj2gco(p), size, memcat, page)
 
 #define luaM_arraysize_(n, e) ((cast_to(size_t, (n)) <= SIZE_MAX / (e)) ? (n) * (e) : (luaM_toobig(L), SIZE_MAX))

VM/src/lobject.h

@@ -15,7 +15,6 @@ typedef union GCObject GCObject;
 */
 // clang-format off
 #define CommonHeader \
-    GCObject* next; /* TODO: remove with FFlagLuauGcPagedSweep */ \
      uint8_t tt; uint8_t marked; uint8_t memcat
 // clang-format on
 
@@ -233,6 +232,8 @@ typedef struct TString
     int16_t atom;
     // 2 byte padding
 
+    TString* next; // next string in the hash table bucket or the string buffer linked list
+
     unsigned int hash;
     unsigned int len;
 
@@ -327,7 +328,7 @@ typedef struct UpVal
             struct UpVal* next;
 
             /* thread double linked list (when open) */
-            // TODO: when FFlagLuauGcPagedSweep is removed, old outer 'next' value will be placed here
+            struct UpVal* threadnext;
             /* note: this is the location of a pointer to this upvalue in the previous element that can be either an UpVal or a lua_State */
             struct UpVal** threadprev;
         } l;

VM/src/lstate.cpp

@@ -10,7 +10,6 @@
 #include "ldo.h"
 #include "ldebug.h"
 
-LUAU_FASTFLAG(LuauGcPagedSweep)
 LUAU_FASTFLAGVARIABLE(LuauReduceStackReallocs, false)
 
 /*
@@ -90,8 +89,6 @@ static void close_state(lua_State* L)
     global_State* g = L->global;
     luaF_close(L, L->stack); /* close all upvalues for this thread */
     luaC_freeall(L);         /* collect all objects */
-    if (!FFlag::LuauGcPagedSweep)
-        LUAU_ASSERT(g->rootgc == obj2gco(L));
     LUAU_ASSERT(g->strbufgc == NULL);
     LUAU_ASSERT(g->strt.nuse == 0);
     luaM_freearray(L, L->global->strt.hash, L->global->strt.size, TString*, 0);
@@ -99,22 +96,20 @@ static void close_state(lua_State* L)
     for (int i = 0; i < LUA_SIZECLASSES; i++)
     {
         LUAU_ASSERT(g->freepages[i] == NULL);
-        if (FFlag::LuauGcPagedSweep)
+        LUAU_ASSERT(g->freegcopages[i] == NULL);
-            LUAU_ASSERT(g->freegcopages[i] == NULL);
     }
-    if (FFlag::LuauGcPagedSweep)
+    LUAU_ASSERT(g->allgcopages == NULL);
-        LUAU_ASSERT(g->allgcopages == NULL);
     LUAU_ASSERT(g->totalbytes == sizeof(LG));
     LUAU_ASSERT(g->memcatbytes[0] == sizeof(LG));
     for (int i = 1; i < LUA_MEMORY_CATEGORIES; i++)
         LUAU_ASSERT(g->memcatbytes[i] == 0);
-    (*g->frealloc)(L, g->ud, L, sizeof(LG), 0);
+    (*g->frealloc)(g->ud, L, sizeof(LG), 0);
 }
 
 lua_State* luaE_newthread(lua_State* L)
 {
     lua_State* L1 = luaM_newgco(L, lua_State, sizeof(lua_State), L->activememcat);
-    luaC_link(L, L1, LUA_TTHREAD);
+    luaC_init(L, L1, LUA_TTHREAD);
     preinit_state(L1, L->global);
     L1->activememcat = L->activememcat; // inherit the active memory category
     stack_init(L1, L);                  /* init stack */
@@ -184,13 +179,11 @@ lua_State* lua_newstate(lua_Alloc f, void* ud)
     int i;
     lua_State* L;
     global_State* g;
-    void* l = (*f)(NULL, ud, NULL, 0, sizeof(LG));
+    void* l = (*f)(ud, NULL, 0, sizeof(LG));
     if (l == NULL)
         return NULL;
     L = (lua_State*)l;
     g = &((LG*)L)->g;
-    if (!FFlag::LuauGcPagedSweep)
-        L->next = NULL;
     L->tt = LUA_TTHREAD;
     L->marked = g->currentwhite = bit2mask(WHITE0BIT, FIXEDBIT);
     L->memcat = 0;
@@ -214,11 +207,6 @@ lua_State* lua_newstate(lua_Alloc f, void* ud)
     setnilvalue(&g->pseudotemp);
     setnilvalue(registry(L));
     g->gcstate = GCSpause;
-    if (!FFlag::LuauGcPagedSweep)
-        g->rootgc = obj2gco(L);
-    g->sweepstrgc = 0;
-    if (!FFlag::LuauGcPagedSweep)
-        g->sweepgc = &g->rootgc;
     g->gray = NULL;
     g->grayagain = NULL;
     g->weak = NULL;
@@ -230,14 +218,10 @@ lua_State* lua_newstate(lua_Alloc f, void* ud)
     for (i = 0; i < LUA_SIZECLASSES; i++)
     {
         g->freepages[i] = NULL;
-        if (FFlag::LuauGcPagedSweep)
+        g->freegcopages[i] = NULL;
-            g->freegcopages[i] = NULL;
-    }
-    if (FFlag::LuauGcPagedSweep)
-    {
-        g->allgcopages = NULL;
-        g->sweepgcopage = NULL;
     }
+    g->allgcopages = NULL;
+    g->sweepgcopage = NULL;
     for (i = 0; i < LUA_T_COUNT; i++)
         g->mt[i] = NULL;
     for (i = 0; i < LUA_UTAG_LIMIT; i++)

VM/src/lstate.h

@@ -142,11 +142,6 @@ typedef struct global_State
     uint8_t gcstate; /* state of garbage collector */
 
 
-    int sweepstrgc;      /* position of sweep in `strt' */
-    // TODO: remove with FFlagLuauGcPagedSweep
-    GCObject* rootgc;    /* list of all collectable objects */
-    // TODO: remove with FFlagLuauGcPagedSweep
-    GCObject** sweepgc;  /* position of sweep in `rootgc' */
     GCObject* gray;      /* list of gray objects */
     GCObject* grayagain; /* list of objects to be traversed atomically */
     GCObject* weak;     /* list of weak tables (to be cleared) */

VM/src/lstring.cpp

@@ -7,8 +7,6 @@
 
 #include <string.h>
 
-LUAU_FASTFLAG(LuauGcPagedSweep)
-
 unsigned int luaS_hash(const char* str, size_t len)
 {
     // Note that this hashing algorithm is replicated in BytecodeBuilder.cpp, BytecodeBuilder::getStringHash
@@ -46,8 +44,6 @@ unsigned int luaS_hash(const char* str, size_t len)
 
 void luaS_resize(lua_State* L, int newsize)
 {
-    if (L->global->gcstate == GCSsweepstring)
-        return; /* cannot resize during GC traverse */
     TString** newhash = luaM_newarray(L, newsize, TString*, 0);
     stringtable* tb = &L->global->strt;
     for (int i = 0; i < newsize; i++)
@@ -58,13 +54,11 @@ void luaS_resize(lua_State* L, int newsize)
         TString* p = tb->hash[i];
         while (p)
         { /* for each node in the list */
-            // TODO (FFlagLuauGcPagedSweep): 'next' type will change after removal of the flag and the cast will not be required
+            TString* next = p->next; /* save next */
-            TString* next = (TString*)p->next; /* save next */
             unsigned int h = p->hash;
             int h1 = lmod(h, newsize); /* new position */
             LUAU_ASSERT(cast_int(h % newsize) == lmod(h, newsize));
-            // TODO (FFlagLuauGcPagedSweep): 'next' type will change after removal of the flag and the cast will not be required
+            p->next = newhash[h1]; /* chain it */
-            p->next = (GCObject*)newhash[h1]; /* chain it */
             newhash[h1] = p;
             p = next;
         }
@@ -91,8 +85,7 @@ static TString* newlstr(lua_State* L, const char* str, size_t l, unsigned int h)
     ts->atom = L->global->cb.useratom ? L->global->cb.useratom(ts->data, l) : -1;
     tb = &L->global->strt;
     h = lmod(h, tb->size);
-    // TODO (FFlagLuauGcPagedSweep): 'next' type will change after removal of the flag and the case will not be required
+    ts->next = tb->hash[h]; /* chain new entry */
-    ts->next = (GCObject*)tb->hash[h]; /* chain new entry */
     tb->hash[h] = ts;
     tb->nuse++;
     if (tb->nuse > cast_to(uint32_t, tb->size) && tb->size <= INT_MAX / 2)
@@ -104,20 +97,9 @@ static void linkstrbuf(lua_State* L, TString* ts)
 {
     global_State* g = L->global;
 
-    if (FFlag::LuauGcPagedSweep)
+    ts->next = g->strbufgc;
-    {
+    g->strbufgc = ts;
-        // TODO (FFlagLuauGcPagedSweep): 'next' type will change after removal of the flag and the cast will not be required
+    ts->marked = luaC_white(g);
-        ts->next = (GCObject*)g->strbufgc;
-        g->strbufgc = ts;
-        ts->marked = luaC_white(g);
-    }
-    else
-    {
-        GCObject* o = obj2gco(ts);
-        o->gch.next = (GCObject*)g->strbufgc;
-        g->strbufgc = gco2ts(o);
-        o->gch.marked = luaC_white(g);
-    }
 }
 
 static void unlinkstrbuf(lua_State* L, TString* ts)
@@ -130,14 +112,12 @@ static void unlinkstrbuf(lua_State* L, TString* ts)
     {
         if (curr == ts)
         {
-            // TODO (FFlagLuauGcPagedSweep): 'next' type will change after removal of the flag and the cast will not be required
+            *p = curr->next;
-            *p = (TString*)curr->next;
             return;
         }
         else
         {
-            // TODO (FFlagLuauGcPagedSweep): 'next' type will change after removal of the flag and the cast will not be required
+            p = &curr->next;
-            p = (TString**)&curr->next;
         }
     }
 
@@ -167,8 +147,7 @@ TString* luaS_buffinish(lua_State* L, TString* ts)
     int bucket = lmod(h, tb->size);
 
     // search if we already have this string in the hash table
-    // TODO (FFlagLuauGcPagedSweep): 'next' type will change after removal of the flag and the cast will not be required
+    for (TString* el = tb->hash[bucket]; el != NULL; el = el->next)
-    for (TString* el = tb->hash[bucket]; el != NULL; el = (TString*)el->next)
     {
         if (el->len == ts->len && memcmp(el->data, ts->data, ts->len) == 0)
         {
@@ -187,8 +166,7 @@ TString* luaS_buffinish(lua_State* L, TString* ts)
 
     // Complete string object
     ts->atom = L->global->cb.useratom ? L->global->cb.useratom(ts->data, ts->len) : -1;
-    // TODO (FFlagLuauGcPagedSweep): 'next' type will change after removal of the flag and the cast will not be required
+    ts->next = tb->hash[bucket]; // chain new entry
-    ts->next = (GCObject*)tb->hash[bucket]; // chain new entry
     tb->hash[bucket] = ts;
 
     tb->nuse++;
@@ -201,8 +179,7 @@ TString* luaS_buffinish(lua_State* L, TString* ts)
 TString* luaS_newlstr(lua_State* L, const char* str, size_t l)
 {
     unsigned int h = luaS_hash(str, l);
-    // TODO (FFlagLuauGcPagedSweep): 'next' type will change after removal of the flag and the cast will not be required
+    for (TString* el = L->global->strt.hash[lmod(h, L->global->strt.size)]; el != NULL; el = el->next)
-    for (TString* el = L->global->strt.hash[lmod(h, L->global->strt.size)]; el != NULL; el = (TString*)el->next)
     {
         if (el->len == l && (memcmp(str, getstr(el), l) == 0))
         {
@@ -217,8 +194,6 @@ TString* luaS_newlstr(lua_State* L, const char* str, size_t l)
 
 static bool unlinkstr(lua_State* L, TString* ts)
 {
-    LUAU_ASSERT(FFlag::LuauGcPagedSweep);
-
     global_State* g = L->global;
 
     TString** p = &g->strt.hash[lmod(ts->hash, g->strt.size)];
@@ -227,14 +202,12 @@ static bool unlinkstr(lua_State* L, TString* ts)
     {
         if (curr == ts)
         {
-            // TODO (FFlagLuauGcPagedSweep): 'next' type will change after removal of the flag and the cast will not be required
+            *p = curr->next;
-            *p = (TString*)curr->next;
             return true;
         }
         else
         {
-            // TODO (FFlagLuauGcPagedSweep): 'next' type will change after removal of the flag and the cast will not be required
+            p = &curr->next;
-            p = (TString**)&curr->next;
         }
     }
 
@@ -243,20 +216,11 @@ static bool unlinkstr(lua_State* L, TString* ts)
 
 void luaS_free(lua_State* L, TString* ts, lua_Page* page)
 {
-    if (FFlag::LuauGcPagedSweep)
+    // Unchain from the string table
-    {
+    if (!unlinkstr(L, ts))
-        // Unchain from the string table
+        unlinkstrbuf(L, ts); // An unlikely scenario when we have a string buffer on our hands
-        if (!unlinkstr(L, ts))
-            unlinkstrbuf(L, ts); // An unlikely scenario when we have a string buffer on our hands
-        else
-            L->global->strt.nuse--;
-
-        luaM_freegco(L, ts, sizestring(ts->len), ts->memcat, page);
-    }
     else
-    {
         L->global->strt.nuse--;
 
-        luaM_free(L, ts, sizestring(ts->len), ts->memcat);
+    luaM_freegco(L, ts, sizestring(ts->len), ts->memcat, page);
-    }
 }

VM/src/ltable.cpp

@@ -425,7 +425,7 @@ static void rehash(lua_State* L, Table* t, const TValue* ek)
 Table* luaH_new(lua_State* L, int narray, int nhash)
 {
     Table* t = luaM_newgco(L, Table, sizeof(Table), L->activememcat);
-    luaC_link(L, t, LUA_TTABLE);
+    luaC_init(L, t, LUA_TTABLE);
     t->metatable = NULL;
     t->flags = cast_byte(~0);
     t->array = NULL;
@@ -742,7 +742,7 @@ int luaH_getn(Table* t)
 Table* luaH_clone(lua_State* L, Table* tt)
 {
     Table* t = luaM_newgco(L, Table, sizeof(Table), L->activememcat);
-    luaC_link(L, t, LUA_TTABLE);
+    luaC_init(L, t, LUA_TTABLE);
     t->metatable = tt->metatable;
     t->flags = tt->flags;
     t->array = NULL;

VM/src/ludata.cpp

@@ -12,7 +12,7 @@ Udata* luaU_newudata(lua_State* L, size_t s, int tag)
     if (s > INT_MAX - sizeof(Udata))
         luaM_toobig(L);
     Udata* u = luaM_newgco(L, Udata, sizeudata(s), L->activememcat);
-    luaC_link(L, u, LUA_TUSERDATA);
+    luaC_init(L, u, LUA_TUSERDATA);
     u->len = int(s);
     u->metatable = NULL;
     LUAU_ASSERT(tag >= 0 && tag <= 255);

fuzz/linter.cpp

@@ -1,10 +1,12 @@
 // This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
 #include <string>
-#include "Luau/TypeInfer.h"
+
-#include "Luau/Linter.h"
 #include "Luau/BuiltinDefinitions.h"
-#include "Luau/ModuleResolver.h"
 #include "Luau/Common.h"
+#include "Luau/Linter.h"
+#include "Luau/ModuleResolver.h"
+#include "Luau/Parser.h"
+#include "Luau/TypeInfer.h"
 
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, size_t Size)
 {

fuzz/luau.proto

@@ -96,11 +96,13 @@ message ExprIndexExpr {
 }
 
 message ExprFunction {
-	repeated Local args = 1;
+	repeated Typename generics = 1;
-	required bool vararg = 2;
+	repeated Typename genericpacks = 2;
-	required StatBlock body = 3;
+	repeated Local args = 3;
-	repeated Type types = 4;
+	required bool vararg = 4;
-	repeated Type rettypes = 5;
+	required StatBlock body = 5;
+	repeated Type types = 6;
+	repeated Type rettypes = 7;
 }
 
 message TableItem {
@@ -153,7 +155,10 @@ message ExprBinary {
 message ExprIfElse {
 	required Expr cond = 1;
 	required Expr then = 2;
-	required Expr else = 3; 
+	oneof else_oneof {
+		Expr else = 3;
+		ExprIfElse elseif = 4;
+	}
 }
 
 message LValue {
@@ -183,6 +188,7 @@ message Stat {
 		StatFunction function = 14;
 		StatLocalFunction local_function = 15;
 		StatTypeAlias type_alias = 16;
+		StatRequireIntoLocalHelper require_into_local = 17;
 	}
 }
 
@@ -276,9 +282,16 @@ message StatLocalFunction {
 }
 
 message StatTypeAlias {
-	required Typename name = 1;
+	required bool export = 1;
-	required Type type = 2;
+	required Typename name = 2;
-	repeated Typename generics = 3;
+	required Type type = 3;
+	repeated Typename generics = 4;
+	repeated Typename genericpacks = 5;
+}
+
+message StatRequireIntoLocalHelper {
+	required Local var = 1;
+	required int32 modulenum = 2;
 }
 
 message Type {
@@ -292,6 +305,8 @@ message Type {
 		TypeIntersection intersection = 7;
 		TypeClass class = 8;
 		TypeRef ref = 9;
+		TypeBoolean boolean = 10;
+		TypeString string = 11;
 	}
 }
 
@@ -301,7 +316,8 @@ message TypePrimitive {
 
 message TypeLiteral {
 	required Typename name = 1;
-	repeated Typename generics = 2;
+	repeated Type generics = 2;
+	repeated Typename genericpacks = 3;
 }
 
 message TypeTableItem {
@@ -320,8 +336,10 @@ message TypeTable {
 }
 
 message TypeFunction {
-	repeated Type args = 1;
+	repeated Typename generics = 1;
-	repeated Type rets = 2;
+	repeated Typename genericpacks = 2;
+	repeated Type args = 3;
+	repeated Type rets = 4;
 	// TODO: vararg?
 }
 
@@ -347,3 +365,16 @@ message TypeRef {
 	required Local prefix = 1;
 	required Typename index = 2;
 }
+
+message TypeBoolean {
+	required bool val = 1;
+}
+
+message TypeString {
+	required string val = 1;
+}
+
+message ModuleSet {
+	optional StatBlock module = 1;
+	required StatBlock program = 2;
+}

fuzz/proto.cpp

@@ -2,16 +2,17 @@
 #include "src/libfuzzer/libfuzzer_macro.h"
 #include "luau.pb.h"
 
-#include "Luau/TypeInfer.h"
 #include "Luau/BuiltinDefinitions.h"
-#include "Luau/ModuleResolver.h"
-#include "Luau/ModuleResolver.h"
-#include "Luau/Compiler.h"
-#include "Luau/Linter.h"
 #include "Luau/BytecodeBuilder.h"
 #include "Luau/Common.h"
+#include "Luau/Compiler.h"
+#include "Luau/Frontend.h"
+#include "Luau/Linter.h"
+#include "Luau/ModuleResolver.h"
+#include "Luau/Parser.h"
 #include "Luau/ToString.h"
 #include "Luau/Transpiler.h"
+#include "Luau/TypeInfer.h"
 
 #include "lua.h"
 #include "lualib.h"
@@ -30,7 +31,7 @@ const bool kFuzzTypes = true;
 
 static_assert(!(kFuzzVM && !kFuzzCompiler), "VM requires the compiler!");
 
-std::string protoprint(const luau::StatBlock& stat, bool types);
+std::vector<std::string> protoprint(const luau::ModuleSet& stat, bool types);
 
 LUAU_FASTINT(LuauTypeInferRecursionLimit)
 LUAU_FASTINT(LuauTypeInferTypePackLoopLimit)
@@ -38,6 +39,7 @@ LUAU_FASTINT(LuauCheckRecursionLimit)
 LUAU_FASTINT(LuauTableTypeMaximumStringifierLength)
 LUAU_FASTINT(LuauTypeInferIterationLimit)
 LUAU_FASTINT(LuauTarjanChildLimit)
+LUAU_FASTFLAG(DebugLuauFreezeArena)
 
 std::chrono::milliseconds kInterruptTimeout(10);
 std::chrono::time_point<std::chrono::system_clock> interruptDeadline;
@@ -135,10 +137,58 @@ int registerTypes(Luau::TypeChecker& env)
 
     return 0;
 }
+struct FuzzFileResolver : Luau::FileResolver
+{
+    std::optional<Luau::SourceCode> readSource(const Luau::ModuleName& name) override
+    {
+        auto it = source.find(name);
+        if (it == source.end())
+            return std::nullopt;
 
-static std::string debugsource;
+        return Luau::SourceCode{it->second, Luau::SourceCode::Module};
+    }
 
-DEFINE_PROTO_FUZZER(const luau::StatBlock& message)
+    std::optional<Luau::ModuleInfo> resolveModule(const Luau::ModuleInfo* context, Luau::AstExpr* expr) override
+    {
+        if (Luau::AstExprGlobal* g = expr->as<Luau::AstExprGlobal>())
+            return Luau::ModuleInfo{g->name.value};
+
+        return std::nullopt;
+    }
+
+    std::string getHumanReadableModuleName(const Luau::ModuleName& name) const override
+    {
+        return name;
+    }
+
+    std::optional<std::string> getEnvironmentForModule(const Luau::ModuleName& name) const override
+    {
+        return std::nullopt;
+    }
+
+    std::unordered_map<Luau::ModuleName, std::string> source;
+};
+
+struct FuzzConfigResolver : Luau::ConfigResolver
+{
+    FuzzConfigResolver()
+    {
+        defaultConfig.mode = Luau::Mode::Nonstrict; // typecheckTwice option will cover Strict mode
+        defaultConfig.enabledLint.warningMask = ~0ull;
+        defaultConfig.parseOptions.captureComments = true;
+    }
+
+    virtual const Luau::Config& getConfig(const Luau::ModuleName& name) const override
+    {
+        return defaultConfig;
+    }
+
+    Luau::Config defaultConfig;
+};
+
+static std::vector<std::string> debugsources;
+
+DEFINE_PROTO_FUZZER(const luau::ModuleSet& message)
 {
     FInt::LuauTypeInferRecursionLimit.value = 100;
     FInt::LuauTypeInferTypePackLoopLimit.value = 100;
@@ -151,91 +201,90 @@ DEFINE_PROTO_FUZZER(const luau::StatBlock& message)
         if (strncmp(flag->name, "Luau", 4) == 0)
             flag->value = true;
 
-    Luau::Allocator allocator;
+    FFlag::DebugLuauFreezeArena.value = true;
-    Luau::AstNameTable names(allocator);
 
-    std::string source = protoprint(message, kFuzzTypes);
+    std::vector<std::string> sources = protoprint(message, kFuzzTypes);
 
     // stash source in a global for easier crash dump debugging
-    debugsource = source;
+    debugsources = sources;
-
-    Luau::ParseResult parseResult = Luau::Parser::parse(source.c_str(), source.size(), names, allocator);
-
-    // "static" here is to accelerate fuzzing process by only creating and populating the type environment once
-    static Luau::NullModuleResolver moduleResolver;
-    static Luau::InternalErrorReporter iceHandler;
-    static Luau::TypeChecker sharedEnv(&moduleResolver, &iceHandler);
-    static int once = registerTypes(sharedEnv);
-    (void)once;
-    static int once2 = (Luau::freeze(sharedEnv.globalTypes), 0);
-    (void)once2;
-
-    iceHandler.onInternalError = [](const char* error) {
-        printf("ICE: %s\n", error);
-        LUAU_ASSERT(!"ICE");
-    };
 
     static bool debug = getenv("LUAU_DEBUG") != 0;
 
     if (debug)
     {
-        fprintf(stdout, "--\n%s\n", source.c_str());
+        for (std::string& source : sources)
+            fprintf(stdout, "--\n%s\n", source.c_str());
         fflush(stdout);
     }
 
-    std::string bytecode;
+    // parse all sources
+    std::vector<std::unique_ptr<Luau::Allocator>> parseAllocators;
+    std::vector<std::unique_ptr<Luau::AstNameTable>> parseNameTables;
 
-    // compile
+    Luau::ParseOptions parseOptions;
-    if (kFuzzCompiler && parseResult.errors.empty())
+    parseOptions.captureComments = true;
+
+    std::vector<Luau::ParseResult> parseResults;
+
+    for (std::string& source : sources)
     {
-        Luau::CompileOptions compileOptions;
+        parseAllocators.push_back(std::make_unique<Luau::Allocator>());
+        parseNameTables.push_back(std::make_unique<Luau::AstNameTable>(*parseAllocators.back()));
 
-        try
+        parseResults.push_back(Luau::Parser::parse(source.c_str(), source.size(), *parseNameTables.back(), *parseAllocators.back(), parseOptions));
-        {
-            Luau::BytecodeBuilder bcb;
-            Luau::compileOrThrow(bcb, parseResult.root, names, compileOptions);
-            bytecode = bcb.getBytecode();
-        }
-        catch (const Luau::CompileError&)
-        {
-            // not all valid ASTs can be compiled due to limits on number of registers
-        }
     }
 
-    // typecheck
+    // typecheck all sources
-    if (kFuzzTypeck && parseResult.root)
-    {
-        Luau::SourceModule sourceModule;
-        sourceModule.root = parseResult.root;
-        sourceModule.mode = Luau::Mode::Nonstrict;
-
-        Luau::TypeChecker typeck(&moduleResolver, &iceHandler);
-        typeck.globalScope = sharedEnv.globalScope;
-
-        Luau::ModulePtr module = nullptr;
-
-        try
-        {
-            module = typeck.check(sourceModule, Luau::Mode::Nonstrict);
-        }
-        catch (std::exception&)
-        {
-            // This catches internal errors that the type checker currently (unfortunately) throws in some cases
-        }
-
-        // lint (note that we need access to types so we need to do this with typeck in scope)
-        if (kFuzzLinter)
-        {
-            Luau::LintOptions lintOptions = {~0u};
-            Luau::lint(parseResult.root, names, sharedEnv.globalScope, module.get(), {}, lintOptions);
-        }
-    }
-
-    // validate sharedEnv post-typecheck; valuable for debugging some typeck crashes but slows fuzzing down
-    // note: it's important for typeck to be destroyed at this point!
     if (kFuzzTypeck)
     {
-        for (auto& p : sharedEnv.globalScope->bindings)
+        static FuzzFileResolver fileResolver;
+        static Luau::NullConfigResolver configResolver;
+        static Luau::FrontendOptions options{true, true};
+        static Luau::Frontend frontend(&fileResolver, &configResolver, options);
+
+        static int once = registerTypes(frontend.typeChecker);
+        (void)once;
+        static int once2 = (Luau::freeze(frontend.typeChecker.globalTypes), 0);
+        (void)once2;
+
+        frontend.iceHandler.onInternalError = [](const char* error) {
+            printf("ICE: %s\n", error);
+            LUAU_ASSERT(!"ICE");
+        };
+
+        // restart
+        frontend.clear();
+        fileResolver.source.clear();
+
+        // load sources
+        for (size_t i = 0; i < sources.size(); i++)
+        {
+            std::string name = "module" + std::to_string(i);
+            fileResolver.source[name] = sources[i];
+        }
+
+        // check sources
+        for (size_t i = 0; i < sources.size(); i++)
+        {
+            std::string name = "module" + std::to_string(i);
+
+            try
+            {
+                Luau::CheckResult result = frontend.check(name, std::nullopt);
+
+                // lint (note that we need access to types so we need to do this with typeck in scope)
+                if (kFuzzLinter && result.errors.empty())
+                    frontend.lint(name, std::nullopt);
+            }
+            catch (std::exception&)
+            {
+                // This catches internal errors that the type checker currently (unfortunately) throws in some cases
+            }
+        }
+
+        // validate sharedEnv post-typecheck; valuable for debugging some typeck crashes but slows fuzzing down
+        // note: it's important for typeck to be destroyed at this point!
+        for (auto& p : frontend.typeChecker.globalScope->bindings)
         {
             Luau::ToStringOptions opts;
             opts.exhaustive = true;
@@ -246,12 +295,44 @@ DEFINE_PROTO_FUZZER(const luau::StatBlock& message)
         }
     }
 
-    if (kFuzzTranspile && parseResult.root)
+    if (kFuzzTranspile)
     {
-        transpileWithTypes(*parseResult.root);
+        for (Luau::ParseResult& parseResult : parseResults)
+        {
+            if (parseResult.root)
+                transpileWithTypes(*parseResult.root);
+        }
     }
 
-    // run resulting bytecode
+    std::string bytecode;
+
+    // compile
+    if (kFuzzCompiler)
+    {
+        for (size_t i = 0; i < parseResults.size(); i++)
+        {
+            Luau::ParseResult& parseResult = parseResults[i];
+            Luau::AstNameTable& parseNameTable = *parseNameTables[i];
+
+            if (parseResult.errors.empty())
+            {
+                Luau::CompileOptions compileOptions;
+
+                try
+                {
+                    Luau::BytecodeBuilder bcb;
+                    Luau::compileOrThrow(bcb, parseResult.root, parseNameTable, compileOptions);
+                    bytecode = bcb.getBytecode();
+                }
+                catch (const Luau::CompileError&)
+                {
+                    // not all valid ASTs can be compiled due to limits on number of registers
+                }
+            }
+        }
+    }
+
+    // run resulting bytecode (from last successfully compiler module)
     if (kFuzzVM && bytecode.size())
     {
         static lua_State* globalState = createGlobalState();

fuzz/protoprint.cpp

@@ -208,6 +208,35 @@ struct ProtoToLuau
         source += std::to_string(name.index() & 0xff);
     }
 
+    template<typename T>
+    void genericidents(const T& node)
+    {
+        if (node.generics_size() || node.genericpacks_size())
+        {
+            source += '<';
+            bool first = true;
+
+            for (size_t i = 0; i < node.generics_size(); ++i)
+            {
+                if (!first)
+                    source += ',';
+                first = false;
+                ident(node.generics(i));
+            }
+
+            for (size_t i = 0; i < node.genericpacks_size(); ++i)
+            {
+                if (!first)
+                    source += ',';
+                first = false;
+                ident(node.genericpacks(i));
+                source += "...";
+            }
+
+            source += '>';
+        }
+    }
+
     void print(const luau::Expr& expr)
     {
         if (expr.has_group())
@@ -240,6 +269,8 @@ struct ProtoToLuau
             print(expr.unary());
         else if (expr.has_binary())
             print(expr.binary());
+        else if (expr.has_ifelse())
+            print(expr.ifelse());
         else
             source += "_";
     }
@@ -350,6 +381,7 @@ struct ProtoToLuau
 
     void function(const luau::ExprFunction& expr)
     {
+        genericidents(expr);
         source += "(";
         for (int i = 0; i < expr.args_size(); ++i)
         {
@@ -478,12 +510,21 @@ struct ProtoToLuau
 
     void print(const luau::ExprIfElse& expr)
     {
-        source += " if ";
+        source += "if ";
         print(expr.cond());
         source += " then ";
         print(expr.then());
-        source += " else ";
+
-        print(expr.else_());
+        if (expr.has_else_())
+        {
+            source += " else ";
+            print(expr.else_());
+        }
+        else if (expr.has_elseif())
+        {
+            source += " else";
+            print(expr.elseif());
+        }
     }
 
     void print(const luau::LValue& expr)
@@ -534,6 +575,8 @@ struct ProtoToLuau
             print(stat.local_function());
         else if (stat.has_type_alias())
             print(stat.type_alias());
+        else if (stat.has_require_into_local())
+            print(stat.require_into_local());
         else
             source += "do end\n";
     }
@@ -804,26 +847,24 @@ struct ProtoToLuau
 
     void print(const luau::StatTypeAlias& stat)
     {
+        if (stat.export_())
+            source += "export ";
+
         source += "type ";
         ident(stat.name());
-
+        genericidents(stat);
-        if (stat.generics_size())
-        {
-            source += '<';
-            for (size_t i = 0; i < stat.generics_size(); ++i)
-            {
-                if (i != 0)
-                    source += ',';
-                ident(stat.generics(i));
-            }
-            source += '>';
-        }
-
         source += " = ";
         print(stat.type());
         source += '\n';
     }
 
+    void print(const luau::StatRequireIntoLocalHelper& stat)
+    {
+        source += "local ";
+        print(stat.var());
+        source += " = require(module" + std::to_string(stat.modulenum() % 2) + ")\n";
+    }
+
     void print(const luau::Type& type)
     {
         if (type.has_primitive())
@@ -844,6 +885,10 @@ struct ProtoToLuau
             print(type.class_());
         else if (type.has_ref())
             print(type.ref());
+        else if (type.has_boolean())
+            print(type.boolean());
+        else if (type.has_string())
+            print(type.string());
         else
             source += "any";
     }
@@ -858,15 +903,28 @@ struct ProtoToLuau
     {
         ident(type.name());
 
-        if (type.generics_size())
+        if (type.generics_size() || type.genericpacks_size())
         {
             source += '<';
+            bool first = true;
+
             for (size_t i = 0; i < type.generics_size(); ++i)
             {
-                if (i != 0)
+                if (!first)
                     source += ',';
-                ident(type.generics(i));
+                first = false;
+                print(type.generics(i));
             }
+
+            for (size_t i = 0; i < type.genericpacks_size(); ++i)
+            {
+                if (!first)
+                    source += ',';
+                first = false;
+                ident(type.genericpacks(i));
+                source += "...";
+            }
+
             source += '>';
         }
     }
@@ -893,6 +951,7 @@ struct ProtoToLuau
 
     void print(const luau::TypeFunction& type)
     {
+        genericidents(type);
         source += '(';
         for (size_t i = 0; i < type.args_size(); ++i)
         {
@@ -950,12 +1009,38 @@ struct ProtoToLuau
         source += '.';
         ident(type.index());
     }
+
+    void print(const luau::TypeBoolean& type)
+    {
+        source += type.val() ? "true" : "false";
+    }
+
+    void print(const luau::TypeString& type)
+    {
+        source += '"';
+        for (char ch : type.val())
+            if (isgraph(ch))
+                source += ch;
+        source += '"';
+    }
 };
 
-std::string protoprint(const luau::StatBlock& stat, bool types)
+std::vector<std::string> protoprint(const luau::ModuleSet& stat, bool types)
 {
+    std::vector<std::string> result;
+
+    if (stat.has_module())
+    {
+        ProtoToLuau printer;
+        printer.types = types;
+        printer.print(stat.module());
+        result.push_back(printer.source);
+    }
+
     ProtoToLuau printer;
     printer.types = types;
-    printer.print(stat);
+    printer.print(stat.program());
-    return printer.source;
+    result.push_back(printer.source);
+
+    return result;
 }

fuzz/prototest.cpp

@@ -2,11 +2,15 @@
 #include "src/libfuzzer/libfuzzer_macro.h"
 #include "luau.pb.h"
 
-std::string protoprint(const luau::StatBlock& stat, bool types);
+std::vector<std::string> protoprint(const luau::ModuleSet& stat, bool types);
 
-DEFINE_PROTO_FUZZER(const luau::StatBlock& message)
+DEFINE_PROTO_FUZZER(const luau::ModuleSet& message)
 {
-    std::string source = protoprint(message, true);
+    std::vector<std::string> sources = protoprint(message, true);
 
-    printf("%s\n", source.c_str());
+    for (size_t i = 0; i < sources.size(); i++)
+    {
+        printf("Module 'l%d':\n", int(i));
+        printf("%s\n", sources[i].c_str());
+    }
 }

fuzz/typeck.cpp

@@ -1,9 +1,11 @@
 // This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
 #include <string>
-#include "Luau/TypeInfer.h"
+
 #include "Luau/BuiltinDefinitions.h"
-#include "Luau/ModuleResolver.h"
 #include "Luau/Common.h"
+#include "Luau/ModuleResolver.h"
+#include "Luau/Parser.h"
+#include "Luau/TypeInfer.h"
 
 LUAU_FASTINT(LuauTypeInferRecursionLimit)
 LUAU_FASTINT(LuauTypeInferTypePackLoopLimit)

tests/Autocomplete.test.cpp

@@ -2752,7 +2752,6 @@ TEST_CASE_FIXTURE(ACFixture, "autocomplete_on_string_singletons")
     ScopedFastFlag sffs[] = {
         {"LuauParseSingletonTypes", true},
         {"LuauSingletonTypes", true},
-        {"LuauRefactorTypeVarQuestions", true},
     };
 
     check(R"(

tests/Conformance.test.cpp

@@ -712,6 +712,47 @@ TEST_CASE("Reference")
     CHECK(dtorhits == 2);
 }
 
+TEST_CASE("ApiTables")
+{
+    StateRef globalState(luaL_newstate(), lua_close);
+    lua_State* L = globalState.get();
+
+    lua_newtable(L);
+    lua_pushnumber(L, 123.0);
+    lua_setfield(L, -2, "key");
+    lua_pushstring(L, "test");
+    lua_rawseti(L, -2, 5);
+
+    // lua_gettable
+    lua_pushstring(L, "key");
+    CHECK(lua_gettable(L, -2) == LUA_TNUMBER);
+    CHECK(lua_tonumber(L, -1) == 123.0);
+    lua_pop(L, 1);
+
+    // lua_getfield
+    CHECK(lua_getfield(L, -1, "key") == LUA_TNUMBER);
+    CHECK(lua_tonumber(L, -1) == 123.0);
+    lua_pop(L, 1);
+
+    // lua_rawgetfield
+    CHECK(lua_rawgetfield(L, -1, "key") == LUA_TNUMBER);
+    CHECK(lua_tonumber(L, -1) == 123.0);
+    lua_pop(L, 1);
+
+    // lua_rawget
+    lua_pushstring(L, "key");
+    CHECK(lua_rawget(L, -2) == LUA_TNUMBER);
+    CHECK(lua_tonumber(L, -1) == 123.0);
+    lua_pop(L, 1);
+
+    // lua_rawgeti
+    CHECK(lua_rawgeti(L, -1, 5) == LUA_TSTRING);
+    CHECK(strcmp(lua_tostring(L, -1), "test") == 0);
+    lua_pop(L, 1);
+
+    lua_pop(L, 1);
+}
+
 TEST_CASE("ApiFunctionCalls")
 {
     StateRef globalState = runConformance("apicalls.lua");
@@ -796,7 +837,7 @@ TEST_CASE("ExceptionObject")
         return ExceptionResult{false, ""};
     };
 
-    auto reallocFunc = [](lua_State* L, void* /*ud*/, void* ptr, size_t /*osize*/, size_t nsize) -> void* {
+    auto reallocFunc = [](void* /*ud*/, void* ptr, size_t /*osize*/, size_t nsize) -> void* {
         if (nsize == 0)
         {
             free(ptr);
@@ -923,4 +964,53 @@ TEST_CASE("StringConversion")
     runConformance("strconv.lua");
 }
 
+TEST_CASE("GCDump")
+{
+    // internal function, declared in lgc.h - not exposed via lua.h
+    extern void luaC_dump(lua_State* L, void* file, const char* (*categoryName)(lua_State* L, uint8_t memcat));
+
+    StateRef globalState(luaL_newstate(), lua_close);
+    lua_State* L = globalState.get();
+
+    // push various objects on stack to cover different paths
+    lua_createtable(L, 1, 2);
+    lua_pushstring(L, "value");
+    lua_setfield(L, -2, "key");
+
+    lua_pushinteger(L, 42);
+    lua_rawseti(L, -2, 1000);
+
+    lua_pushinteger(L, 42);
+    lua_rawseti(L, -2, 1);
+
+    lua_pushvalue(L, -1);
+    lua_setmetatable(L, -2);
+
+    lua_newuserdata(L, 42);
+    lua_pushvalue(L, -2);
+    lua_setmetatable(L, -2);
+
+    lua_pushinteger(L, 1);
+    lua_pushcclosure(L, lua_silence, "test", 1);
+
+    lua_State* CL = lua_newthread(L);
+
+    lua_pushstring(CL, "local x x = {} local function f() x[1] = math.abs(42) end function foo() coroutine.yield() end foo() return f");
+    lua_loadstring(CL);
+    lua_resume(CL, nullptr, 0);
+
+#ifdef _WIN32
+    const char* path = "NUL";
+#else
+    const char* path = "/dev/null";
+#endif
+
+    FILE* f = fopen(path, "w");
+    REQUIRE(f);
+
+    luaC_dump(L, f, nullptr);
+
+    fclose(f);
+}
+
 TEST_SUITE_END();

tests/Linter.test.cpp

@@ -1594,4 +1594,17 @@ TEST_CASE_FIXTURE(Fixture, "WrongCommentMuteSelf")
     REQUIRE_EQ(result.warnings.size(), 0); // --!nolint disables WrongComment lint :)
 }
 
+TEST_CASE_FIXTURE(Fixture, "DuplicateConditionsIfStatAndExpr")
+{
+    LintResult result = lint(R"(
+if if 1 then 2 else 3 then
+elseif if 1 then 2 else 3 then
+elseif if 0 then 5 else 4 then
+end
+)");
+
+    REQUIRE_EQ(result.warnings.size(), 1);
+    CHECK_EQ(result.warnings[0].text, "Condition has already been checked on line 2");
+}
+
 TEST_SUITE_END();

tests/Parser.test.cpp

@@ -2575,7 +2575,6 @@ do end
 TEST_CASE_FIXTURE(Fixture, "recover_expected_type_pack")
 {
     ScopedFastFlag luauParseTypeAliasDefaults{"LuauParseTypeAliasDefaults", true};
-    ScopedFastFlag luauParseRecoverTypePackEllipsis{"LuauParseRecoverTypePackEllipsis", true};
 
     ParseResult result = tryParse(R"(
 type Y<T..., U = T...> = (T...) -> U...

tests/Transpiler.test.cpp

@@ -651,4 +651,19 @@ local a: Packed<number>
 
     CHECK_EQ(code, transpile(code, {}, true).code);
 }
+
+TEST_CASE_FIXTURE(Fixture, "transpile_singleton_types")
+{
+    ScopedFastFlag luauParseSingletonTypes{"LuauParseSingletonTypes", true};
+
+    std::string code = R"(
+type t1 = 'hello'
+type t2 = true
+type t3 = ''
+type t4 = false
+    )";
+
+    CHECK_EQ(code, transpile(code, {}, true).code);
+}
+
 TEST_SUITE_END();

tests/TypeInfer.intersectionTypes.test.cpp

@@ -175,6 +175,8 @@ TEST_CASE_FIXTURE(Fixture, "index_on_an_intersection_type_with_property_guarante
 
 TEST_CASE_FIXTURE(Fixture, "index_on_an_intersection_type_works_at_arbitrary_depth")
 {
+    ScopedFastFlag sff{"LuauDoNotTryToReduce", true};
+
     CheckResult result = check(R"(
         type A = {x: {y: {z: {thing: string}}}}
         type B = {x: {y: {z: {thing: string}}}}
@@ -184,7 +186,7 @@ TEST_CASE_FIXTURE(Fixture, "index_on_an_intersection_type_works_at_arbitrary_dep
     )");
 
     LUAU_REQUIRE_NO_ERRORS(result);
-    CHECK_EQ(*typeChecker.stringType, *requireType("r"));
+    CHECK_EQ("string & string", toString(requireType("r")));
 }
 
 TEST_CASE_FIXTURE(Fixture, "index_on_an_intersection_type_with_mixed_types")
@@ -218,7 +220,7 @@ TEST_CASE_FIXTURE(Fixture, "index_on_an_intersection_type_with_one_part_missing_
 TEST_CASE_FIXTURE(Fixture, "index_on_an_intersection_type_with_one_property_of_type_any")
 {
     CheckResult result = check(R"(
-        type A = {x: number}
+        type A = {y: number}
         type B = {x: any}
         local t: A & B
 

tests/TypeInfer.refinements.test.cpp

@@ -1115,6 +1115,22 @@ TEST_CASE_FIXTURE(Fixture, "discriminate_on_properties_of_disjoint_tables_where_
     LUAU_REQUIRE_NO_ERRORS(result);
 }
 
+TEST_CASE_FIXTURE(Fixture, "refine_a_property_not_to_be_nil_through_an_intersection_table")
+{
+    ScopedFastFlag sff{"LuauDoNotTryToReduce", true};
+
+    CheckResult result = check(R"(
+        type T = {} & {f: ((string) -> string)?}
+        local function f(t: T, x)
+            if t.f then
+                t.f(x)
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+}
+
 TEST_CASE_FIXTURE(RefinementClassFixture, "discriminate_from_isa_of_x")
 {
     ScopedFastFlag sff[] = {

tests/TypeInfer.singletons.test.cpp

@@ -439,4 +439,128 @@ local a: Animal = if true then { tag = 'cat', catfood = 'something' } else { tag
     LUAU_REQUIRE_NO_ERRORS(result);
 }
 
+TEST_CASE_FIXTURE(Fixture, "widen_the_supertype_if_it_is_free_and_subtype_has_singleton")
+{
+    ScopedFastFlag sff[]{
+        {"LuauSingletonTypes", true},
+        {"LuauEqConstraint", true},
+        {"LuauDiscriminableUnions2", true},
+        {"LuauWidenIfSupertypeIsFree", true},
+        {"LuauWeakEqConstraint", false},
+    };
+
+    CheckResult result = check(R"(
+        local function foo(f, x)
+            if x == "hi" then
+                f(x)
+                f("foo")
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+
+    CHECK_EQ(R"("hi")", toString(requireTypeAtPosition({3, 18})));
+    // should be <a...>((string) -> a..., string) -> () but needs lower bounds calculation
+    CHECK_EQ("<a, b...>((string) -> (b...), a) -> ()", toString(requireType("foo")));
+}
+
+// TEST_CASE_FIXTURE(Fixture, "return_type_of_f_is_not_widened")
+// {
+//     ScopedFastFlag sff[]{
+//         {"LuauParseSingletonTypes", true},
+//         {"LuauSingletonTypes", true},
+//         {"LuauDiscriminableUnions2", true},
+//         {"LuauEqConstraint", true},
+//         {"LuauWidenIfSupertypeIsFree", true},
+//         {"LuauWeakEqConstraint", false},
+//     };
+
+//     CheckResult result = check(R"(
+//         local function foo(f, x): "hello"? -- anyone there?
+//             return if x == "hi"
+//                 then f(x)
+//                 else nil
+//         end
+//     )");
+
+//     LUAU_REQUIRE_NO_ERRORS(result);
+
+//     CHECK_EQ(R"("hi")", toString(requireTypeAtPosition({3, 23})));
+//     CHECK_EQ(R"(<a, b...>((string) -> ("hello"?, b...), a) -> "hello"?)", toString(requireType("foo")));
+// }
+
+TEST_CASE_FIXTURE(Fixture, "widening_happens_almost_everywhere")
+{
+    ScopedFastFlag sff[]{
+        {"LuauParseSingletonTypes", true},
+        {"LuauSingletonTypes", true},
+        {"LuauWidenIfSupertypeIsFree", true},
+    };
+
+    CheckResult result = check(R"(
+        local foo: "foo" = "foo"
+        local copy = foo
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("string", toString(requireType("copy")));
+}
+
+TEST_CASE_FIXTURE(Fixture, "widening_happens_almost_everywhere_except_for_tables")
+{
+    ScopedFastFlag sff[]{
+        {"LuauParseSingletonTypes", true},
+        {"LuauSingletonTypes", true},
+        {"LuauDiscriminableUnions2", true},
+        {"LuauWidenIfSupertypeIsFree", true},
+    };
+
+    CheckResult result = check(R"(
+        type Cat = {tag: "Cat", meows: boolean}
+        type Dog = {tag: "Dog", barks: boolean}
+        type Animal = Cat | Dog
+
+        local function f(tag: "Cat" | "Dog"): Animal?
+            if tag == "Cat" then
+                local result = {tag = tag, meows = true}
+                return result
+            elseif tag == "Dog" then
+                local result = {tag = tag, barks = true}
+                return result
+            else
+                return nil
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+}
+
+TEST_CASE_FIXTURE(Fixture, "table_insert_with_a_singleton_argument")
+{
+    ScopedFastFlag sff[]{
+        {"LuauParseSingletonTypes", true},
+        {"LuauSingletonTypes", true},
+        {"LuauWidenIfSupertypeIsFree", true},
+    };
+
+    CheckResult result = check(R"(
+        local function foo(t, x)
+            if x == "hi" or x == "bye" then
+                table.insert(t, x)
+            end
+
+            return t
+        end
+
+        local t = foo({}, "hi")
+        table.insert(t, "totally_unrelated_type" :: "totally_unrelated_type")
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+
+    CHECK_EQ("{string}", toString(requireType("t")));
+}
+
 TEST_SUITE_END();

tests/TypeInfer.tables.test.cpp

@@ -2239,4 +2239,22 @@ TEST_CASE_FIXTURE(Fixture, "give_up_after_one_metatable_index_look_up")
     CHECK_EQ("Type 't2' does not have key 'x'", toString(result.errors[0]));
 }
 
+TEST_CASE_FIXTURE(Fixture, "confusing_indexing")
+{
+    ScopedFastFlag sff{"LuauDoNotTryToReduce", true};
+
+    CheckResult result = check(R"(
+        type T = {} & {p: number | string}
+        local function f(t: T)
+            return t.p
+        end
+
+        local foo = f({p = "string"})
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+
+    CHECK_EQ("number | string", toString(requireType("foo")));
+}
+
 TEST_SUITE_END();

tests/TypeInfer.test.cpp

@@ -5127,8 +5127,6 @@ TEST_CASE_FIXTURE(Fixture, "cli_50041_committing_txnlog_in_apollo_client_error")
 
 TEST_CASE_FIXTURE(Fixture, "do_not_modify_imported_types")
 {
-    ScopedFastFlag noSealedTypeMod{"LuauNoSealedTypeMod", true};
-
     fileResolver.source["game/A"] = R"(
 export type Type = { unrelated: boolean }
 return {}
@@ -5190,7 +5188,6 @@ TEST_CASE_FIXTURE(Fixture, "indexing_on_string_singletons")
 {
     ScopedFastFlag sff[]{
         {"LuauDiscriminableUnions2", true},
-        {"LuauRefactorTypeVarQuestions", true},
         {"LuauSingletonTypes", true},
     };
 
@@ -5210,7 +5207,6 @@ TEST_CASE_FIXTURE(Fixture, "indexing_on_union_of_string_singletons")
 {
     ScopedFastFlag sff[]{
         {"LuauDiscriminableUnions2", true},
-        {"LuauRefactorTypeVarQuestions", true},
         {"LuauSingletonTypes", true},
     };
 
@@ -5230,7 +5226,6 @@ TEST_CASE_FIXTURE(Fixture, "taking_the_length_of_string_singleton")
 {
     ScopedFastFlag sff[]{
         {"LuauDiscriminableUnions2", true},
-        {"LuauRefactorTypeVarQuestions", true},
         {"LuauSingletonTypes", true},
     };
 
@@ -5250,7 +5245,6 @@ TEST_CASE_FIXTURE(Fixture, "taking_the_length_of_union_of_string_singleton")
 {
     ScopedFastFlag sff[]{
         {"LuauDiscriminableUnions2", true},
-        {"LuauRefactorTypeVarQuestions", true},
         {"LuauSingletonTypes", true},
     };
 

tests/TypeInfer.tryUnify.test.cpp

@@ -19,7 +19,7 @@ struct TryUnifyFixture : Fixture
     ScopePtr globalScope{new Scope{arena.addTypePack({TypeId{}})}};
     InternalErrorReporter iceHandler;
     UnifierSharedState unifierState{&iceHandler};
-    Unifier state{&arena, Mode::Strict, globalScope, Location{}, Variance::Covariant, unifierState};
+    Unifier state{&arena, Mode::Strict, Location{}, Variance::Covariant, unifierState};
 };
 
 TEST_SUITE_BEGIN("TryUnifyTests");
@@ -261,8 +261,6 @@ TEST_CASE_FIXTURE(TryUnifyFixture, "free_tail_is_grown_properly")
 
 TEST_CASE_FIXTURE(TryUnifyFixture, "recursive_metatable_getmatchtag")
 {
-    ScopedFastFlag luauUnionTagMatchFix{"LuauUnionTagMatchFix", true};
-
     TypeVar redirect{FreeTypeVar{TypeLevel{}}};
     TypeVar table{TableTypeVar{}};
     TypeVar metatable{MetatableTypeVar{&redirect, &table}};

tests/TypeVar.test.cpp

@@ -361,16 +361,12 @@ local b: (T, T, T) -> T
 
 TEST_CASE("isString_on_string_singletons")
 {
-    ScopedFastFlag sff{"LuauRefactorTypeVarQuestions", true};
-
     TypeVar helloString{SingletonTypeVar{StringSingleton{"hello"}}};
     CHECK(isString(&helloString));
 }
 
 TEST_CASE("isString_on_unions_of_various_string_singletons")
 {
-    ScopedFastFlag sff{"LuauRefactorTypeVarQuestions", true};
-
     TypeVar helloString{SingletonTypeVar{StringSingleton{"hello"}}};
     TypeVar byeString{SingletonTypeVar{StringSingleton{"bye"}}};
     TypeVar union_{UnionTypeVar{{&helloString, &byeString}}};
@@ -380,8 +376,6 @@ TEST_CASE("isString_on_unions_of_various_string_singletons")
 
 TEST_CASE("proof_that_isString_uses_all_of")
 {
-    ScopedFastFlag sff{"LuauRefactorTypeVarQuestions", true};
-
     TypeVar helloString{SingletonTypeVar{StringSingleton{"hello"}}};
     TypeVar byeString{SingletonTypeVar{StringSingleton{"bye"}}};
     TypeVar booleanType{PrimitiveTypeVar{PrimitiveTypeVar::Boolean}};
@@ -392,16 +386,12 @@ TEST_CASE("proof_that_isString_uses_all_of")
 
 TEST_CASE("isBoolean_on_boolean_singletons")
 {
-    ScopedFastFlag sff{"LuauRefactorTypeVarQuestions", true};
-
     TypeVar trueBool{SingletonTypeVar{BooleanSingleton{true}}};
     CHECK(isBoolean(&trueBool));
 }
 
 TEST_CASE("isBoolean_on_unions_of_true_or_false_singletons")
 {
-    ScopedFastFlag sff{"LuauRefactorTypeVarQuestions", true};
-
     TypeVar trueBool{SingletonTypeVar{BooleanSingleton{true}}};
     TypeVar falseBool{SingletonTypeVar{BooleanSingleton{false}}};
     TypeVar union_{UnionTypeVar{{&trueBool, &falseBool}}};
@@ -411,8 +401,6 @@ TEST_CASE("isBoolean_on_unions_of_true_or_false_singletons")
 
 TEST_CASE("proof_that_isBoolean_uses_all_of")
 {
-    ScopedFastFlag sff{"LuauRefactorTypeVarQuestions", true};
-
     TypeVar trueBool{SingletonTypeVar{BooleanSingleton{true}}};
     TypeVar falseBool{SingletonTypeVar{BooleanSingleton{false}}};
     TypeVar stringType{PrimitiveTypeVar{PrimitiveTypeVar::String}};

tools/natvis/VM.natvis

@@ -183,13 +183,12 @@
         <Expand>
           <LinkedListItems>
             <HeadPointer>openupval</HeadPointer>
-            <NextPointer>u.l.next</NextPointer>
+            <NextPointer>u.l.threadnext</NextPointer>
             <ValueNode>this</ValueNode>
           </LinkedListItems>
         </Expand>
       </Synthetic>
-      <Item Name="l_gt">l_gt</Item>
+      <Item Name="globals">gt</Item>
-      <Item Name="env">env</Item>
       <Item Name="userdata">userdata</Item>
     </Expand>
   </Type>