Sync to upstream/release/650 (#1502)

* New `vector` library! See https://rfcs.luau.org/vector-library.html
for details
* Replace the use of non-portable `strnlen` with `memchr`. `strnlen` is
not part of any C or C++ standard.
* Introduce `lua_newuserdatataggedwithmetatable` for faster tagged
userdata creation of userdata with metatables registered with
`lua_setuserdatametatable`

Old Solver

* It used to be the case that a module's result type would
unconditionally be inferred to be `any` if it imported any module that
participates in any import cycle. This is now fixed.

New Solver

* Improve inference of `table.freeze`: We now infer read-only properties
on tables after they have been frozen.
* We now correctly flag cases where `string.format` is called with 0
arguments.
* Fix a bug in user-defined type functions where table properties could
be lost if the table had a metatable
* Reset the random number seed for each evaluation of a type function
* We now retry subtyping arguments if it failed due to hidden variadics.

---------

Co-authored-by: Aaron Weiss <aaronweiss@roblox.com>
Co-authored-by: Alexander McCord <amccord@roblox.com>
Co-authored-by: Vighnesh <vvijay@roblox.com>
Co-authored-by: Aviral Goel <agoel@roblox.com>
Co-authored-by: David Cope <dcope@roblox.com>
Co-authored-by: Lily Brown <lbrown@roblox.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
Co-authored-by: Junseo Yoo <jyoo@roblox.com>

Analysis/include/Luau/TypeFunctionRuntime.h

@@ -265,4 +265,6 @@ void registerTypeUserData(lua_State* L);
 
 void setTypeFunctionEnvironment(lua_State* L);
 
+void resetTypeFunctionState(lua_State* L);
+
 } // namespace Luau

Analysis/src/AnyTypeSummary.cpp

@@ -38,7 +38,7 @@
 
 #include <stdio.h>
 
-LUAU_FASTFLAGVARIABLE(StudioReportLuauAny2, false);
+LUAU_FASTFLAGVARIABLE(StudioReportLuauAny2);
 LUAU_FASTINTVARIABLE(LuauAnySummaryRecursionLimit, 300);
 
 LUAU_FASTFLAG(DebugLuauMagicTypes);

Analysis/src/AstQuery.cpp

@@ -13,7 +13,7 @@
 
 LUAU_FASTFLAG(LuauSolverV2)
 
-LUAU_FASTFLAGVARIABLE(LuauDocumentationAtPosition, false)
+LUAU_FASTFLAGVARIABLE(LuauDocumentationAtPosition)
 
 namespace Luau
 {

Analysis/src/Autocomplete.cpp

@@ -16,7 +16,7 @@
 #include <utility>
 
 LUAU_FASTFLAG(LuauSolverV2)
-LUAU_FASTFLAGVARIABLE(AutocompleteRequirePathSuggestions, false)
+LUAU_FASTFLAGVARIABLE(AutocompleteRequirePathSuggestions)
 
 LUAU_DYNAMIC_FASTINT(LuauTypeSolverRelease)
 LUAU_FASTINT(LuauTypeInferIterationLimit)

Analysis/src/BuiltinDefinitions.cpp

@@ -3,6 +3,7 @@
 
 #include "Luau/Ast.h"
 #include "Luau/Clone.h"
+#include "Luau/DenseHash.h"
 #include "Luau/Error.h"
 #include "Luau/Frontend.h"
 #include "Luau/Symbol.h"
@@ -29,8 +30,8 @@
 
 LUAU_FASTFLAG(LuauSolverV2)
 LUAU_DYNAMIC_FASTINT(LuauTypeSolverRelease)
-LUAU_FASTFLAGVARIABLE(LuauTypestateBuiltins, false)
-LUAU_FASTFLAGVARIABLE(LuauStringFormatArityFix, false)
+LUAU_FASTFLAGVARIABLE(LuauTypestateBuiltins2)
+LUAU_FASTFLAGVARIABLE(LuauStringFormatArityFix)
 
 LUAU_FASTFLAG(AutocompleteRequirePathSuggestions)
 
@@ -421,7 +422,7 @@ void registerBuiltinGlobals(Frontend& frontend, GlobalTypes& globals, bool typeC
 
         attachMagicFunction(ttv->props["pack"].type(), magicFunctionPack);
         attachDcrMagicFunction(ttv->props["pack"].type(), dcrMagicFunctionPack);
-        if (FFlag::LuauTypestateBuiltins)
+        if (FFlag::LuauTypestateBuiltins2)
             attachDcrMagicFunction(ttv->props["freeze"].type(), dcrMagicFunctionFreeze);
     }
 
@@ -1338,54 +1339,86 @@ static bool dcrMagicFunctionPack(MagicFunctionCallContext context)
     return true;
 }
 
+static std::optional<TypeId> freezeTable(TypeId inputType, MagicFunctionCallContext& context)
+{
+    TypeArena* arena = context.solver->arena;
+
+    if (auto mt = get<MetatableType>(inputType))
+    {
+        std::optional<TypeId> frozenTable = freezeTable(mt->table, context);
+
+        if (!frozenTable)
+            return std::nullopt;
+
+        TypeId resultType = arena->addType(MetatableType{*frozenTable, mt->metatable, mt->syntheticName});
+
+        return resultType;
+    }
+
+    if (get<TableType>(inputType))
+    {
+        // Clone the input type, this will become our final result type after we mutate it.
+        CloneState cloneState{context.solver->builtinTypes};
+        TypeId resultType = shallowClone(inputType, *arena, cloneState);
+        auto tableTy = getMutable<TableType>(resultType);
+        // `clone` should not break this.
+        LUAU_ASSERT(tableTy);
+        tableTy->state = TableState::Sealed;
+
+        // We'll mutate the table to make every property type read-only.
+        for (auto iter = tableTy->props.begin(); iter != tableTy->props.end();)
+        {
+            if (iter->second.isWriteOnly())
+                iter = tableTy->props.erase(iter);
+            else
+            {
+                iter->second.writeTy = std::nullopt;
+                iter++;
+            }
+        }
+
+        return resultType;
+    }
+
+    context.solver->reportError(TypeMismatch{context.solver->builtinTypes->tableType, inputType}, context.callSite->argLocation);
+    return std::nullopt;
+}
+
 static bool dcrMagicFunctionFreeze(MagicFunctionCallContext context)
 {
-    LUAU_ASSERT(FFlag::LuauTypestateBuiltins);
+    LUAU_ASSERT(FFlag::LuauTypestateBuiltins2);
 
     TypeArena* arena = context.solver->arena;
     const DataFlowGraph* dfg = context.solver->dfg.get();
     Scope* scope = context.constraint->scope.get();
 
     const auto& [paramTypes, paramTail] = extendTypePack(*arena, context.solver->builtinTypes, context.arguments, 1);
-    LUAU_ASSERT(paramTypes.size() >= 1);
-
-    TypeId inputType = follow(paramTypes.at(0));
-
-    // we'll check if it's a table first since this magic function also produces the error if it's not until we have bounded generics
-    if (!get<TableType>(inputType))
+    if (paramTypes.empty() || context.callSite->args.size == 0)
     {
-        context.solver->reportError(TypeMismatch{context.solver->builtinTypes->tableType, inputType}, context.callSite->argLocation);
+        context.solver->reportError(CountMismatch{1, std::nullopt, 0}, context.callSite->argLocation);
         return false;
     }
 
+    TypeId inputType = follow(paramTypes[0]);
+
     AstExpr* targetExpr = context.callSite->args.data[0];
     std::optional<DefId> resultDef = dfg->getDefOptional(targetExpr);
     std::optional<TypeId> resultTy = resultDef ? scope->lookup(*resultDef) : std::nullopt;
 
-    // Clone the input type, this will become our final result type after we mutate it.
-    CloneState cloneState{context.solver->builtinTypes};
-    TypeId clonedType = shallowClone(inputType, *arena, cloneState);
-    auto tableTy = getMutable<TableType>(clonedType);
-    // `clone` should not break this.
-    LUAU_ASSERT(tableTy);
-    tableTy->state = TableState::Sealed;
-    tableTy->syntheticName = std::nullopt;
+    std::optional<TypeId> frozenType = freezeTable(inputType, context);
 
-    // We'll mutate the table to make every property type read-only.
-    for (auto iter = tableTy->props.begin(); iter != tableTy->props.end();)
+    if (!frozenType)
     {
-        if (iter->second.isWriteOnly())
-            iter = tableTy->props.erase(iter);
-        else
-        {
-            iter->second.writeTy = std::nullopt;
-            iter++;
-        }
+        if (resultTy)
+            asMutable(*resultTy)->ty.emplace<BoundType>(context.solver->builtinTypes->errorType);
+        asMutable(context.result)->ty.emplace<BoundTypePack>(context.solver->builtinTypes->errorTypePack);
+
+        return true;
     }
 
     if (resultTy)
-        asMutable(*resultTy)->ty.emplace<BoundType>(clonedType);
-    asMutable(context.result)->ty.emplace<BoundTypePack>(arena->addTypePack({clonedType}));
+        asMutable(*resultTy)->ty.emplace<BoundType>(*frozenType);
+    asMutable(context.result)->ty.emplace<BoundTypePack>(arena->addTypePack({*frozenType}));
 
     return true;
 }

Analysis/src/ConstraintGenerator.cpp

@@ -31,9 +31,9 @@ LUAU_FASTINT(LuauCheckRecursionLimit)
 LUAU_FASTFLAG(DebugLuauLogSolverToJson)
 LUAU_FASTFLAG(DebugLuauMagicTypes)
 LUAU_DYNAMIC_FASTINT(LuauTypeSolverRelease)
-LUAU_FASTFLAG(LuauTypestateBuiltins)
+LUAU_FASTFLAG(LuauTypestateBuiltins2)
 
-LUAU_FASTFLAGVARIABLE(LuauNewSolverVisitErrorExprLvalues, false)
+LUAU_FASTFLAGVARIABLE(LuauNewSolverVisitErrorExprLvalues)
 
 namespace Luau
 {
@@ -1078,7 +1078,7 @@ ControlFlow ConstraintGenerator::visit(const ScopePtr& scope, AstStatLocal* stat
             addConstraint(scope, value->location, NameConstraint{*firstValueType, var->name.value, /*synthetic*/ true});
         else if (const AstExprCall* call = value->as<AstExprCall>())
         {
-            if (FFlag::LuauTypestateBuiltins)
+            if (FFlag::LuauTypestateBuiltins2)
             {
                 if (matchSetMetatable(*call))
                     addConstraint(scope, value->location, NameConstraint{*firstValueType, var->name.value, /*synthetic*/ true});
@@ -2062,7 +2062,7 @@ InferencePack ConstraintGenerator::checkPack(const ScopePtr& scope, AstExprCall*
         return InferencePack{arena->addTypePack({resultTy}), {refinementArena.variadic(returnRefinements)}};
     }
 
-    if (FFlag::LuauTypestateBuiltins && shouldTypestateForFirstArgument(*call) && call->args.size > 0 && isLValue(call->args.data[0]))
+    if (FFlag::LuauTypestateBuiltins2 && shouldTypestateForFirstArgument(*call) && call->args.size > 0 && isLValue(call->args.data[0]))
     {
         AstExpr* targetExpr = call->args.data[0];
         auto resultTy = arena->addType(BlockedType{});

Analysis/src/ConstraintSolver.cpp

@@ -27,12 +27,12 @@
 #include <algorithm>
 #include <utility>
 
-LUAU_FASTFLAGVARIABLE(DebugLuauLogSolver, false)
-LUAU_FASTFLAGVARIABLE(DebugLuauLogSolverIncludeDependencies, false)
-LUAU_FASTFLAGVARIABLE(DebugLuauLogBindings, false)
+LUAU_FASTFLAGVARIABLE(DebugLuauLogSolver)
+LUAU_FASTFLAGVARIABLE(DebugLuauLogSolverIncludeDependencies)
+LUAU_FASTFLAGVARIABLE(DebugLuauLogBindings)
 LUAU_FASTINTVARIABLE(LuauSolverRecursionLimit, 500)
 LUAU_DYNAMIC_FASTINT(LuauTypeSolverRelease)
-LUAU_FASTFLAGVARIABLE(LuauRemoveNotAnyHack, false)
+LUAU_FASTFLAGVARIABLE(LuauRemoveNotAnyHack)
 
 namespace Luau
 {

Analysis/src/DataFlowGraph.cpp

@@ -13,7 +13,7 @@
 
 LUAU_FASTFLAG(DebugLuauFreezeArena)
 LUAU_FASTFLAG(LuauSolverV2)
-LUAU_FASTFLAG(LuauTypestateBuiltins)
+LUAU_FASTFLAG(LuauTypestateBuiltins2)
 
 namespace Luau
 {
@@ -939,7 +939,7 @@ DataFlowResult DataFlowGraphBuilder::visitExpr(AstExprCall* c)
 {
     visitExpr(c->func);
 
-    if (FFlag::LuauTypestateBuiltins && shouldTypestateForFirstArgument(*c) && c->args.size > 1 && isLValue(*c->args.begin()))
+    if (FFlag::LuauTypestateBuiltins2 && shouldTypestateForFirstArgument(*c) && c->args.size > 1 && isLValue(*c->args.begin()))
     {
         AstExpr* firstArg = *c->args.begin();
 

Analysis/src/EmbeddedBuiltinDefinitions.cpp

@@ -3,6 +3,8 @@
 
 LUAU_FASTFLAG(LuauMathMap)
 
+LUAU_FASTFLAGVARIABLE(LuauVectorDefinitions)
+
 namespace Luau
 {
 
@@ -450,9 +452,39 @@ declare buffer: {
 
 )BUILTIN_SRC";
 
+static const std::string kBuiltinDefinitionVectorSrc = R"BUILTIN_SRC(
+
+-- TODO: this will be replaced with a built-in primitive type
+declare class vector end
+
+declare vector: {
+    create: @checked (x: number, y: number, z: number) -> vector,
+    magnitude: @checked (vec: vector) -> number,
+    normalize: @checked (vec: vector) -> vector,
+    cross: @checked (vec1: vector, vec2: vector) -> vector,
+    dot: @checked (vec1: vector, vec2: vector) -> number,
+    angle: @checked (vec1: vector, vec2: vector, axis: vector?) -> number,
+    floor: @checked (vec: vector) -> vector,
+    ceil: @checked (vec: vector) -> vector,
+    abs: @checked (vec: vector) -> vector,
+    sign: @checked (vec: vector) -> vector,
+    clamp: @checked (vec: vector, min: vector, max: vector) -> vector,
+    max: @checked (vector, ...vector) -> vector,
+    min: @checked (vector, ...vector) -> vector,
+
+    zero: vector,
+    one: vector,
+}
+
+)BUILTIN_SRC";
+
 std::string getBuiltinDefinitionSource()
 {
     std::string result = FFlag::LuauMathMap ? kBuiltinDefinitionLuaSrcChecked : kBuiltinDefinitionLuaSrcChecked_DEPRECATED;
+
+    if (FFlag::LuauVectorDefinitions)
+        result += kBuiltinDefinitionVectorSrc;
+
     return result;
 }
 

Analysis/src/Frontend.cpp

@@ -36,20 +36,20 @@ LUAU_FASTINT(LuauTypeInferIterationLimit)
 LUAU_FASTINT(LuauTypeInferRecursionLimit)
 LUAU_FASTINT(LuauTarjanChildLimit)
 LUAU_FASTFLAG(LuauInferInNoCheckMode)
-LUAU_FASTFLAGVARIABLE(LuauKnowsTheDataModel3, false)
-LUAU_FASTFLAGVARIABLE(LuauStoreCommentsForDefinitionFiles, false)
+LUAU_FASTFLAGVARIABLE(LuauKnowsTheDataModel3)
+LUAU_FASTFLAGVARIABLE(LuauStoreCommentsForDefinitionFiles)
 LUAU_FASTFLAG(LuauSolverV2)
-LUAU_FASTFLAGVARIABLE(DebugLuauLogSolverToJson, false)
-LUAU_FASTFLAGVARIABLE(DebugLuauLogSolverToJsonFile, false)
-LUAU_FASTFLAGVARIABLE(DebugLuauForbidInternalTypes, false)
-LUAU_FASTFLAGVARIABLE(DebugLuauForceStrictMode, false)
-LUAU_FASTFLAGVARIABLE(DebugLuauForceNonStrictMode, false)
-LUAU_FASTFLAGVARIABLE(LuauUserDefinedTypeFunctionNoEvaluation, false)
+LUAU_FASTFLAGVARIABLE(DebugLuauLogSolverToJson)
+LUAU_FASTFLAGVARIABLE(DebugLuauLogSolverToJsonFile)
+LUAU_FASTFLAGVARIABLE(DebugLuauForbidInternalTypes)
+LUAU_FASTFLAGVARIABLE(DebugLuauForceStrictMode)
+LUAU_FASTFLAGVARIABLE(DebugLuauForceNonStrictMode)
+LUAU_FASTFLAGVARIABLE(LuauUserDefinedTypeFunctionNoEvaluation)
 LUAU_DYNAMIC_FASTFLAGVARIABLE(LuauRunCustomModuleChecks, false)
-LUAU_FASTFLAGVARIABLE(LuauMoreThoroughCycleDetection, false)
+LUAU_FASTFLAGVARIABLE(LuauMoreThoroughCycleDetection)
 
 LUAU_FASTFLAG(StudioReportLuauAny2)
-LUAU_FASTFLAGVARIABLE(LuauStoreDFGOnModule2, false)
+LUAU_FASTFLAGVARIABLE(LuauStoreDFGOnModule2)
 
 namespace Luau
 {

Analysis/src/Linter.cpp

@@ -18,7 +18,7 @@ LUAU_FASTFLAG(LuauSolverV2)
 
 LUAU_FASTFLAG(LuauAttribute)
 LUAU_FASTFLAG(LuauNativeAttribute)
-LUAU_FASTFLAGVARIABLE(LintRedundantNativeAttribute, false)
+LUAU_FASTFLAGVARIABLE(LintRedundantNativeAttribute)
 
 namespace Luau
 {

Analysis/src/NonStrictTypeChecker.cpp

@@ -19,6 +19,8 @@
 #include <iostream>
 #include <iterator>
 
+LUAU_FASTFLAGVARIABLE(LuauUserTypeFunNonstrict)
+
 namespace Luau
 {
 
@@ -421,7 +423,9 @@ struct NonStrictTypeChecker
 
     NonStrictContext visit(AstStatTypeFunction* typeFunc)
     {
-        reportError(GenericError{"This syntax is not supported"}, typeFunc->location);
+        if (!FFlag::LuauUserTypeFunNonstrict)
+            reportError(GenericError{"This syntax is not supported"}, typeFunc->location);
+
         return {};
     }
 

Analysis/src/Normalize.cpp

@@ -15,14 +15,14 @@
 #include "Luau/TypeFwd.h"
 #include "Luau/Unifier.h"
 
-LUAU_FASTFLAGVARIABLE(DebugLuauCheckNormalizeInvariant, false)
+LUAU_FASTFLAGVARIABLE(DebugLuauCheckNormalizeInvariant)
 
 LUAU_FASTINTVARIABLE(LuauNormalizeCacheLimit, 100000);
 LUAU_FASTFLAG(LuauSolverV2);
 
 LUAU_FASTINTVARIABLE(LuauNormalizeIntersectionLimit, 200)
-LUAU_FASTFLAGVARIABLE(LuauNormalizationTracksCyclicPairsThroughInhabitance, false);
-LUAU_FASTFLAGVARIABLE(LuauIntersectNormalsNeedsToTrackResourceLimits, false);
+LUAU_FASTFLAGVARIABLE(LuauNormalizationTracksCyclicPairsThroughInhabitance);
+LUAU_FASTFLAGVARIABLE(LuauIntersectNormalsNeedsToTrackResourceLimits);
 
 namespace Luau
 {

Analysis/src/Simplify.cpp

@@ -15,7 +15,7 @@
 LUAU_FASTINT(LuauTypeReductionRecursionLimit)
 LUAU_FASTFLAG(LuauSolverV2)
 LUAU_DYNAMIC_FASTINTVARIABLE(LuauSimplificationComplexityLimit, 8);
-LUAU_FASTFLAGVARIABLE(LuauFlagBasicIntersectFollows, false);
+LUAU_FASTFLAGVARIABLE(LuauFlagBasicIntersectFollows);
 
 namespace Luau
 {

Analysis/src/Subtyping.cpp

@@ -21,8 +21,9 @@
 
 #include <algorithm>
 
-LUAU_FASTFLAGVARIABLE(DebugLuauSubtypingCheckPathValidity, false);
+LUAU_FASTFLAGVARIABLE(DebugLuauSubtypingCheckPathValidity)
 LUAU_DYNAMIC_FASTINT(LuauTypeSolverRelease)
+LUAU_FASTFLAGVARIABLE(LuauRetrySubtypingWithoutHiddenPack)
 
 namespace Luau
 {
@@ -1477,6 +1478,20 @@ SubtypingResult Subtyping::isCovariantWith(
         result.orElse(
             isContravariantWith(env, subFunction->argTypes, superFunction->argTypes, scope).withBothComponent(TypePath::PackField::Arguments)
         );
+
+        // If subtyping failed in the argument packs, we should check if there's a hidden variadic tail and try ignoring it.
+        // This might cause subtyping correctly because the sub type here may not have a hidden variadic tail or equivalent.
+        if (FFlag::LuauRetrySubtypingWithoutHiddenPack && !result.isSubtype)
+        {
+            auto [arguments, tail] = flatten(superFunction->argTypes);
+
+            if (auto variadic = get<VariadicTypePack>(tail); variadic && variadic->hidden)
+            {
+                result.orElse(
+                    isContravariantWith(env, subFunction->argTypes, arena->addTypePack(TypePack{arguments}), scope).withBothComponent(TypePath::PackField::Arguments)
+                );
+            }
+        }
     }
 
     result.andAlso(isCovariantWith(env, subFunction->retTypes, superFunction->retTypes, scope).withBothComponent(TypePath::PackField::Returns));

Analysis/src/ToString.cpp

@@ -38,7 +38,7 @@ LUAU_FASTFLAG(LuauSolverV2)
  * 3: Suffix free/generic types with their scope pointer, if present.
  */
 LUAU_FASTINTVARIABLE(DebugLuauVerboseTypeNames, 0)
-LUAU_FASTFLAGVARIABLE(DebugLuauToStringNoLexicalSort, false)
+LUAU_FASTFLAGVARIABLE(DebugLuauToStringNoLexicalSort)
 
 namespace Luau
 {

Analysis/src/TypeArena.cpp

@@ -2,7 +2,7 @@
 
 #include "Luau/TypeArena.h"
 
-LUAU_FASTFLAGVARIABLE(DebugLuauFreezeArena, false);
+LUAU_FASTFLAGVARIABLE(DebugLuauFreezeArena);
 
 namespace Luau
 {

Analysis/src/TypeFunction.cpp

@@ -45,11 +45,12 @@ LUAU_DYNAMIC_FASTINTVARIABLE(LuauTypeFamilyApplicationCartesianProductLimit, 5'0
 // when this value is set to a negative value, guessing will be totally disabled.
 LUAU_DYNAMIC_FASTINTVARIABLE(LuauTypeFamilyUseGuesserDepth, -1);
 
-LUAU_FASTFLAGVARIABLE(DebugLuauLogTypeFamilies, false)
-LUAU_FASTFLAGVARIABLE(LuauUserDefinedTypeFunctions2, false)
+LUAU_FASTFLAGVARIABLE(DebugLuauLogTypeFamilies)
+LUAU_FASTFLAGVARIABLE(LuauUserDefinedTypeFunctions2)
 LUAU_FASTFLAG(LuauUserDefinedTypeFunctionNoEvaluation)
 LUAU_FASTFLAG(LuauUserTypeFunFixRegister)
 LUAU_FASTFLAG(LuauRemoveNotAnyHack)
+LUAU_FASTFLAGVARIABLE(LuauUserDefinedTypeFunctionResetState)
 
 LUAU_DYNAMIC_FASTINT(LuauTypeSolverRelease)
 
@@ -645,6 +646,9 @@ TypeFunctionReductionResult<TypeId> userDefinedTypeFunction(
     lua_getglobal(global, name.value);
     lua_xmove(global, L, 1);
 
+    if (FFlag::LuauUserDefinedTypeFunctionResetState)
+        resetTypeFunctionState(L);
+
     // Push serialized arguments onto the stack
 
     // Since there aren't any new class types being created in type functions, there isn't a deserialization function

Analysis/src/TypeFunctionRuntime.cpp

@@ -15,8 +15,8 @@
 
 LUAU_DYNAMIC_FASTINT(LuauTypeFunctionSerdeIterationLimit)
 LUAU_DYNAMIC_FASTINT(LuauTypeSolverRelease)
-LUAU_FASTFLAGVARIABLE(LuauUserTypeFunFixRegister, false)
-LUAU_FASTFLAGVARIABLE(LuauUserTypeFunFixNoReadWrite, false)
+LUAU_FASTFLAGVARIABLE(LuauUserTypeFunFixRegister)
+LUAU_FASTFLAGVARIABLE(LuauUserTypeFunFixNoReadWrite)
 
 namespace Luau
 {
@@ -1647,6 +1647,15 @@ void setTypeFunctionEnvironment(lua_State* L)
     }
 }
 
+void resetTypeFunctionState(lua_State* L)
+{
+    lua_getglobal(L, "math");
+    lua_getfield(L, -1, "randomseed");
+    lua_pushnumber(L, 0);
+    lua_call(L, 1, 0);
+    lua_pop(L, 1);
+}
+
 /*
  * Below are helper methods for __eq
  * Same as one from Type.cpp

Analysis/src/TypeFunctionRuntimeBuilder.cpp

@@ -20,6 +20,8 @@
 // currently, controls serialization, deserialization, and `type.copy`
 LUAU_DYNAMIC_FASTINTVARIABLE(LuauTypeFunctionSerdeIterationLimit, 100'000);
 
+LUAU_FASTFLAGVARIABLE(LuauUserTypeFunFixMetatable)
+
 namespace Luau
 {
 
@@ -241,31 +243,31 @@ private:
         return target;
     }
 
-    void serializeChildren(TypeId ty, TypeFunctionTypeId tfti)
+    void serializeChildren(const TypeId ty, TypeFunctionTypeId tfti)
     {
-        if (auto [p1, p2] = std::tuple{getMutable<PrimitiveType>(ty), getMutable<TypeFunctionPrimitiveType>(tfti)}; p1 && p2)
+        if (auto [p1, p2] = std::tuple{get<PrimitiveType>(ty), getMutable<TypeFunctionPrimitiveType>(tfti)}; p1 && p2)
             serializeChildren(p1, p2);
-        else if (auto [u1, u2] = std::tuple{getMutable<UnknownType>(ty), getMutable<TypeFunctionUnknownType>(tfti)}; u1 && u2)
+        else if (auto [u1, u2] = std::tuple{get<UnknownType>(ty), getMutable<TypeFunctionUnknownType>(tfti)}; u1 && u2)
             serializeChildren(u1, u2);
-        else if (auto [n1, n2] = std::tuple{getMutable<NeverType>(ty), getMutable<TypeFunctionNeverType>(tfti)}; n1 && n2)
+        else if (auto [n1, n2] = std::tuple{get<NeverType>(ty), getMutable<TypeFunctionNeverType>(tfti)}; n1 && n2)
             serializeChildren(n1, n2);
-        else if (auto [a1, a2] = std::tuple{getMutable<AnyType>(ty), getMutable<TypeFunctionAnyType>(tfti)}; a1 && a2)
+        else if (auto [a1, a2] = std::tuple{get<AnyType>(ty), getMutable<TypeFunctionAnyType>(tfti)}; a1 && a2)
             serializeChildren(a1, a2);
-        else if (auto [s1, s2] = std::tuple{getMutable<SingletonType>(ty), getMutable<TypeFunctionSingletonType>(tfti)}; s1 && s2)
+        else if (auto [s1, s2] = std::tuple{get<SingletonType>(ty), getMutable<TypeFunctionSingletonType>(tfti)}; s1 && s2)
             serializeChildren(s1, s2);
-        else if (auto [u1, u2] = std::tuple{getMutable<UnionType>(ty), getMutable<TypeFunctionUnionType>(tfti)}; u1 && u2)
+        else if (auto [u1, u2] = std::tuple{get<UnionType>(ty), getMutable<TypeFunctionUnionType>(tfti)}; u1 && u2)
             serializeChildren(u1, u2);
-        else if (auto [i1, i2] = std::tuple{getMutable<IntersectionType>(ty), getMutable<TypeFunctionIntersectionType>(tfti)}; i1 && i2)
+        else if (auto [i1, i2] = std::tuple{get<IntersectionType>(ty), getMutable<TypeFunctionIntersectionType>(tfti)}; i1 && i2)
             serializeChildren(i1, i2);
-        else if (auto [n1, n2] = std::tuple{getMutable<NegationType>(ty), getMutable<TypeFunctionNegationType>(tfti)}; n1 && n2)
+        else if (auto [n1, n2] = std::tuple{get<NegationType>(ty), getMutable<TypeFunctionNegationType>(tfti)}; n1 && n2)
             serializeChildren(n1, n2);
-        else if (auto [t1, t2] = std::tuple{getMutable<TableType>(ty), getMutable<TypeFunctionTableType>(tfti)}; t1 && t2)
+        else if (auto [t1, t2] = std::tuple{get<TableType>(ty), getMutable<TypeFunctionTableType>(tfti)}; t1 && t2)
             serializeChildren(t1, t2);
-        else if (auto [m1, m2] = std::tuple{getMutable<MetatableType>(ty), getMutable<TypeFunctionTableType>(tfti)}; m1 && m2)
+        else if (auto [m1, m2] = std::tuple{get<MetatableType>(ty), getMutable<TypeFunctionTableType>(tfti)}; m1 && m2)
             serializeChildren(m1, m2);
-        else if (auto [f1, f2] = std::tuple{getMutable<FunctionType>(ty), getMutable<TypeFunctionFunctionType>(tfti)}; f1 && f2)
+        else if (auto [f1, f2] = std::tuple{get<FunctionType>(ty), getMutable<TypeFunctionFunctionType>(tfti)}; f1 && f2)
             serializeChildren(f1, f2);
-        else if (auto [c1, c2] = std::tuple{getMutable<ClassType>(ty), getMutable<TypeFunctionClassType>(tfti)}; c1 && c2)
+        else if (auto [c1, c2] = std::tuple{get<ClassType>(ty), getMutable<TypeFunctionClassType>(tfti)}; c1 && c2)
             serializeChildren(c1, c2);
         else
         { // Either this or ty and tfti do not represent the same type
@@ -274,12 +276,11 @@ private:
         }
     }
 
-    void serializeChildren(TypePackId tp, TypeFunctionTypePackId tftp)
+    void serializeChildren(const TypePackId tp, TypeFunctionTypePackId tftp)
     {
-        if (auto [tPack1, tPack2] = std::tuple{getMutable<TypePack>(tp), getMutable<TypeFunctionTypePack>(tftp)}; tPack1 && tPack2)
+        if (auto [tPack1, tPack2] = std::tuple{get<TypePack>(tp), getMutable<TypeFunctionTypePack>(tftp)}; tPack1 && tPack2)
             serializeChildren(tPack1, tPack2);
-        else if (auto [vPack1, vPack2] = std::tuple{getMutable<VariadicTypePack>(tp), getMutable<TypeFunctionVariadicTypePack>(tftp)};
-                 vPack1 && vPack2)
+        else if (auto [vPack1, vPack2] = std::tuple{get<VariadicTypePack>(tp), getMutable<TypeFunctionVariadicTypePack>(tftp)}; vPack1 && vPack2)
             serializeChildren(vPack1, vPack2);
         else
         { // Either this or ty and tfti do not represent the same type
@@ -298,49 +299,49 @@ private:
             state->ctx->ice->ice("Serializing user defined type function arguments: kind and tfkind do not represent the same type");
     }
 
-    void serializeChildren(PrimitiveType* p1, TypeFunctionPrimitiveType* p2)
+    void serializeChildren(const PrimitiveType* p1, TypeFunctionPrimitiveType* p2)
     {
         // noop.
     }
 
-    void serializeChildren(UnknownType* u1, TypeFunctionUnknownType* u2)
+    void serializeChildren(const UnknownType* u1, TypeFunctionUnknownType* u2)
     {
         // noop.
     }
 
-    void serializeChildren(NeverType* n1, TypeFunctionNeverType* n2)
+    void serializeChildren(const NeverType* n1, TypeFunctionNeverType* n2)
     {
         // noop.
     }
 
-    void serializeChildren(AnyType* a1, TypeFunctionAnyType* a2)
+    void serializeChildren(const AnyType* a1, TypeFunctionAnyType* a2)
     {
         // noop.
     }
 
-    void serializeChildren(SingletonType* s1, TypeFunctionSingletonType* s2)
+    void serializeChildren(const SingletonType* s1, TypeFunctionSingletonType* s2)
     {
         // noop.
     }
 
-    void serializeChildren(UnionType* u1, TypeFunctionUnionType* u2)
+    void serializeChildren(const UnionType* u1, TypeFunctionUnionType* u2)
     {
-        for (TypeId& ty : u1->options)
+        for (const TypeId& ty : u1->options)
             u2->components.push_back(shallowSerialize(ty));
     }
 
-    void serializeChildren(IntersectionType* i1, TypeFunctionIntersectionType* i2)
+    void serializeChildren(const IntersectionType* i1, TypeFunctionIntersectionType* i2)
     {
-        for (TypeId& ty : i1->parts)
+        for (const TypeId& ty : i1->parts)
             i2->components.push_back(shallowSerialize(ty));
     }
 
-    void serializeChildren(NegationType* n1, TypeFunctionNegationType* n2)
+    void serializeChildren(const NegationType* n1, TypeFunctionNegationType* n2)
     {
         n2->type = shallowSerialize(n1->ty);
     }
 
-    void serializeChildren(TableType* t1, TypeFunctionTableType* t2)
+    void serializeChildren(const TableType* t1, TypeFunctionTableType* t2)
     {
         for (const auto& [k, p] : t1->props)
         {
@@ -359,25 +360,34 @@ private:
             t2->indexer = TypeFunctionTableIndexer(shallowSerialize(t1->indexer->indexType), shallowSerialize(t1->indexer->indexResultType));
     }
 
-    void serializeChildren(MetatableType* m1, TypeFunctionTableType* m2)
+    void serializeChildren(const MetatableType* m1, TypeFunctionTableType* m2)
     {
-        auto tmpTable = get<TypeFunctionTableType>(shallowSerialize(m1->table));
-        if (!tmpTable)
-            state->ctx->ice->ice("Serializing user defined type function arguments: metatable's table is not a TableType");
+        if (FFlag::LuauUserTypeFunFixMetatable)
+        {
+            // Serialize main part of the metatable immediately
+            if (auto tableTy = get<TableType>(m1->table))
+                serializeChildren(tableTy, m2);
+        }
+        else
+        {
+            auto tmpTable = get<TypeFunctionTableType>(shallowSerialize(m1->table));
+            if (!tmpTable)
+                state->ctx->ice->ice("Serializing user defined type function arguments: metatable's table is not a TableType");
 
-        m2->props = tmpTable->props;
-        m2->indexer = tmpTable->indexer;
+            m2->props = tmpTable->props;
+            m2->indexer = tmpTable->indexer;
+        }
 
         m2->metatable = shallowSerialize(m1->metatable);
     }
 
-    void serializeChildren(FunctionType* f1, TypeFunctionFunctionType* f2)
+    void serializeChildren(const FunctionType* f1, TypeFunctionFunctionType* f2)
     {
         f2->argTypes = shallowSerialize(f1->argTypes);
         f2->retTypes = shallowSerialize(f1->retTypes);
     }
 
-    void serializeChildren(ClassType* c1, TypeFunctionClassType* c2)
+    void serializeChildren(const ClassType* c1, TypeFunctionClassType* c2)
     {
         for (const auto& [k, p] : c1->props)
         {
@@ -402,16 +412,16 @@ private:
             c2->parent = shallowSerialize(*c1->parent);
     }
 
-    void serializeChildren(TypePack* t1, TypeFunctionTypePack* t2)
+    void serializeChildren(const TypePack* t1, TypeFunctionTypePack* t2)
     {
-        for (TypeId& ty : t1->head)
+        for (const TypeId& ty : t1->head)
             t2->head.push_back(shallowSerialize(ty));
 
         if (t1->tail.has_value())
             t2->tail = shallowSerialize(*t1->tail);
     }
 
-    void serializeChildren(VariadicTypePack* v1, TypeFunctionVariadicTypePack* v2)
+    void serializeChildren(const VariadicTypePack* v1, TypeFunctionVariadicTypePack* v2)
     {
         v2->type = shallowSerialize(v1->ty);
     }

Analysis/src/TypeInfer.cpp

@@ -23,16 +23,18 @@
 #include <algorithm>
 #include <iterator>
 
-LUAU_FASTFLAGVARIABLE(DebugLuauMagicTypes, false)
+LUAU_FASTFLAGVARIABLE(DebugLuauMagicTypes)
 LUAU_FASTINTVARIABLE(LuauTypeInferRecursionLimit, 165)
 LUAU_FASTINTVARIABLE(LuauTypeInferIterationLimit, 20000)
 LUAU_FASTINTVARIABLE(LuauTypeInferTypePackLoopLimit, 5000)
 LUAU_FASTINTVARIABLE(LuauCheckRecursionLimit, 300)
 LUAU_FASTINTVARIABLE(LuauVisitRecursionLimit, 500)
 LUAU_FASTFLAG(LuauKnowsTheDataModel3)
-LUAU_FASTFLAGVARIABLE(DebugLuauFreezeDuringUnification, false)
+LUAU_FASTFLAGVARIABLE(DebugLuauFreezeDuringUnification)
 LUAU_FASTFLAG(LuauInstantiateInSubtyping)
-LUAU_FASTFLAGVARIABLE(LuauAcceptIndexingTableUnionsIntersections, false)
+LUAU_FASTFLAGVARIABLE(LuauAcceptIndexingTableUnionsIntersections)
+LUAU_FASTFLAGVARIABLE(LuauMetatableFollow)
+LUAU_FASTFLAGVARIABLE(LuauRequireCyclesDontAlwaysReturnAny)
 
 namespace Luau
 {
@@ -263,10 +265,17 @@ ModulePtr TypeChecker::checkWithoutRecursionCheck(const SourceModule& module, Mo
     ScopePtr parentScope = environmentScope.value_or(globalScope);
     ScopePtr moduleScope = std::make_shared<Scope>(parentScope);
 
-    if (module.cyclic)
-        moduleScope->returnType = addTypePack(TypePack{{anyType}, std::nullopt});
-    else
+    if (FFlag::LuauRequireCyclesDontAlwaysReturnAny)
+    {
         moduleScope->returnType = freshTypePack(moduleScope);
+    }
+    else
+    {
+        if (module.cyclic)
+            moduleScope->returnType = addTypePack(TypePack{{anyType}, std::nullopt});
+        else
+            moduleScope->returnType = freshTypePack(moduleScope);
+    }
 
     moduleScope->varargPack = anyTypePack;
 
@@ -2870,7 +2879,7 @@ TypeId TypeChecker::checkRelationalOperation(
             std::optional<TypeId> metamethod = findMetatableEntry(lhsType, metamethodName, expr.location, /* addErrors= */ true);
             if (metamethod)
             {
-                if (const FunctionType* ftv = get<FunctionType>(*metamethod))
+                if (const FunctionType* ftv = get<FunctionType>(FFlag::LuauMetatableFollow ? follow(*metamethod) : *metamethod))
                 {
                     if (isEquality)
                     {

Analysis/src/Unifier.cpp

@@ -17,11 +17,11 @@
 
 LUAU_FASTINT(LuauTypeInferTypePackLoopLimit)
 LUAU_FASTFLAG(LuauErrorRecoveryType)
-LUAU_FASTFLAGVARIABLE(LuauInstantiateInSubtyping, false)
-LUAU_FASTFLAGVARIABLE(LuauTransitiveSubtyping, false)
+LUAU_FASTFLAGVARIABLE(LuauInstantiateInSubtyping)
+LUAU_FASTFLAGVARIABLE(LuauTransitiveSubtyping)
 LUAU_FASTFLAG(LuauSolverV2)
-LUAU_FASTFLAGVARIABLE(LuauFixIndexerSubtypingOrdering, false)
-LUAU_FASTFLAGVARIABLE(LuauUnifierRecursionOnRestart, false)
+LUAU_FASTFLAGVARIABLE(LuauFixIndexerSubtypingOrdering)
+LUAU_FASTFLAGVARIABLE(LuauUnifierRecursionOnRestart)
 
 namespace Luau
 {

Ast/include/Luau/Parser.h

@@ -217,7 +217,7 @@ private:
     AstType* parseTableType(bool inDeclarationContext = false);
     AstTypeOrPack parseSimpleType(bool allowPack, bool inDeclarationContext = false);
 
-    AstTypeOrPack parseTypeOrPack();
+    AstTypeOrPack parseSimpleTypeOrPack();
     AstType* parseType(bool inDeclarationContext = false);
 
     AstTypePack* parseTypePack();

Ast/src/Parser.cpp

@@ -8,6 +8,7 @@
 
 #include <errno.h>
 #include <limits.h>
+#include <string.h>
 
 LUAU_FASTINTVARIABLE(LuauRecursionLimit, 1000)
 LUAU_FASTINTVARIABLE(LuauTypeLengthLimit, 1000)
@@ -16,11 +17,12 @@ LUAU_FASTINTVARIABLE(LuauParseErrorLimit, 100)
 // Warning: If you are introducing new syntax, ensure that it is behind a separate
 // flag so that we don't break production games by reverting syntax changes.
 // See docs/SyntaxChanges.md for an explanation.
-LUAU_FASTFLAGVARIABLE(LuauSolverV2, false)
-LUAU_FASTFLAGVARIABLE(LuauNativeAttribute, false)
-LUAU_FASTFLAGVARIABLE(LuauAttributeSyntaxFunExpr, false)
-LUAU_FASTFLAGVARIABLE(LuauUserDefinedTypeFunctionsSyntax2, false)
-LUAU_FASTFLAGVARIABLE(LuauAllowFragmentParsing, false)
+LUAU_FASTFLAGVARIABLE(LuauSolverV2)
+LUAU_FASTFLAGVARIABLE(LuauNativeAttribute)
+LUAU_FASTFLAGVARIABLE(LuauAttributeSyntaxFunExpr)
+LUAU_FASTFLAGVARIABLE(LuauUserDefinedTypeFunctionsSyntax2)
+LUAU_FASTFLAGVARIABLE(LuauAllowFragmentParsing)
+LUAU_FASTFLAGVARIABLE(LuauPortableStringZeroCheck)
 
 namespace Luau
 {
@@ -1131,7 +1133,8 @@ AstStat* Parser::parseDeclaration(const Location& start, const AstArray<AstAttr*
                 AstType* type = parseType();
 
                 // since AstName contains a char*, it can't contain null
-                bool containsNull = chars && (strnlen(chars->data, chars->size) < chars->size);
+                bool containsNull = chars && (FFlag::LuauPortableStringZeroCheck ? memchr(chars->data, 0, chars->size) != nullptr
+                                                                                 : strnlen(chars->data, chars->size) < chars->size);
 
                 if (chars && !containsNull)
                 {
@@ -1609,7 +1612,8 @@ AstType* Parser::parseTableType(bool inDeclarationContext)
             AstType* type = parseType();
 
             // since AstName contains a char*, it can't contain null
-            bool containsNull = chars && (strnlen(chars->data, chars->size) < chars->size);
+            bool containsNull = chars && (FFlag::LuauPortableStringZeroCheck ? memchr(chars->data, 0, chars->size) != nullptr
+                                                                             : strnlen(chars->data, chars->size) < chars->size);
 
             if (chars && !containsNull)
                 props.push_back(AstTableProp{AstName(chars->data), begin.location, type, access, accessLocation});
@@ -1858,7 +1862,7 @@ AstType* Parser::parseTypeSuffix(AstType* type, const Location& begin)
     ParseError::raise(begin, "Composite type was not an intersection or union.");
 }
 
-AstTypeOrPack Parser::parseTypeOrPack()
+AstTypeOrPack Parser::parseSimpleTypeOrPack()
 {
     unsigned int oldRecursionCount = recursionCounter;
     // recursion counter is incremented in parseSimpleType
@@ -2873,7 +2877,7 @@ std::pair<AstArray<AstGenericType>, AstArray<AstGenericTypePack>> Parser::parseG
                     }
                     else
                     {
-                        auto [type, typePack] = parseTypeOrPack();
+                        auto [type, typePack] = parseSimpleTypeOrPack();
 
                         if (type)
                             report(type->location, "Expected type pack after '=', got type");
@@ -2950,7 +2954,7 @@ AstArray<AstTypeOrPack> Parser::parseTypeParams()
             }
             else if (lexer.current().type == '(')
             {
-                auto [type, typePack] = parseTypeOrPack();
+                auto [type, typePack] = parseSimpleTypeOrPack();
 
                 if (typePack)
                     parameters.push_back({{}, typePack});

Ast/src/TimeTrace.cpp

@@ -26,7 +26,7 @@
 
 #include <time.h>
 
-LUAU_FASTFLAGVARIABLE(DebugLuauTimeTracing, false)
+LUAU_FASTFLAGVARIABLE(DebugLuauTimeTracing)
 namespace Luau
 {
 namespace TimeTrace

CodeGen/src/BytecodeAnalysis.cpp

@@ -515,6 +515,40 @@ static void applyBuiltinCall(int bfid, BytecodeTypes& types)
         types.a = LBC_TYPE_TABLE;
         types.b = LBC_TYPE_TABLE;
         break;
+    case LBF_VECTOR_MAGNITUDE:
+        types.result = LBC_TYPE_NUMBER;
+        types.a = LBC_TYPE_VECTOR;
+        break;
+    case LBF_VECTOR_NORMALIZE:
+        types.result = LBC_TYPE_VECTOR;
+        types.a = LBC_TYPE_VECTOR;
+        break;
+    case LBF_VECTOR_CROSS:
+        types.result = LBC_TYPE_VECTOR;
+        types.a = LBC_TYPE_VECTOR;
+        types.b = LBC_TYPE_VECTOR;
+        break;
+    case LBF_VECTOR_DOT:
+        types.result = LBC_TYPE_NUMBER;
+        types.a = LBC_TYPE_VECTOR;
+        types.b = LBC_TYPE_VECTOR;
+        break;
+    case LBF_VECTOR_FLOOR:
+    case LBF_VECTOR_CEIL:
+    case LBF_VECTOR_ABS:
+    case LBF_VECTOR_SIGN:
+    case LBF_VECTOR_CLAMP:
+        types.result = LBC_TYPE_VECTOR;
+        types.a = LBC_TYPE_VECTOR;
+        types.b = LBC_TYPE_VECTOR;
+        break;
+    case LBF_VECTOR_MIN:
+    case LBF_VECTOR_MAX:
+        types.result = LBC_TYPE_VECTOR;
+        types.a = LBC_TYPE_VECTOR;
+        types.b = LBC_TYPE_VECTOR;
+        types.c = LBC_TYPE_VECTOR; // We can mark optional arguments
+        break;
     }
 }
 

CodeGen/src/CodeGen.cpp

@@ -41,9 +41,9 @@
 #endif
 #endif
 
-LUAU_FASTFLAGVARIABLE(DebugCodegenNoOpt, false)
-LUAU_FASTFLAGVARIABLE(DebugCodegenOptSize, false)
-LUAU_FASTFLAGVARIABLE(DebugCodegenSkipNumbering, false)
+LUAU_FASTFLAGVARIABLE(DebugCodegenNoOpt)
+LUAU_FASTFLAGVARIABLE(DebugCodegenOptSize)
+LUAU_FASTFLAGVARIABLE(DebugCodegenSkipNumbering)
 
 // Per-module IR instruction count limit
 LUAU_FASTINTVARIABLE(CodegenHeuristicsInstructionLimit, 1'048'576) // 1 M

CodeGen/src/CodeGenUtils.cpp

@@ -226,9 +226,10 @@ Udata* newUserdata(lua_State* L, size_t s, int tag)
 
     if (Table* h = L->global->udatamt[tag])
     {
-        u->metatable = h;
+        // currently, we always allocate unmarked objects, so forward barrier can be skipped
+        LUAU_ASSERT(!isblack(obj2gco(u)));
 
-        luaC_objbarrier(L, u, h);
+        u->metatable = h;
     }
 
     return u;

CodeGen/src/IrRegAllocA64.cpp

@@ -10,7 +10,7 @@
 
 #include <string.h>
 
-LUAU_FASTFLAGVARIABLE(DebugCodegenChaosA64, false)
+LUAU_FASTFLAGVARIABLE(DebugCodegenChaosA64)
 
 namespace Luau
 {

CodeGen/src/IrTranslateBuiltins.cpp

@@ -13,6 +13,8 @@
 static const int kMinMaxUnrolledParams = 5;
 static const int kBit32BinaryOpUnrolledParams = 5;
 
+LUAU_FASTFLAGVARIABLE(LuauVectorLibNativeCodegen);
+
 namespace Luau
 {
 namespace CodeGen
@@ -885,6 +887,300 @@ static BuiltinImplResult translateBuiltinBufferWrite(
     return {BuiltinImplType::Full, 0};
 }
 
+static BuiltinImplResult translateBuiltinVectorMagnitude(
+    IrBuilder& build,
+    int nparams,
+    int ra,
+    int arg,
+    IrOp args,
+    IrOp arg3,
+    int nresults,
+    int pcpos
+)
+{
+    LUAU_ASSERT(FFlag::LuauVectorLibNativeCodegen);
+
+    IrOp arg1 = build.vmReg(arg);
+
+    if (nparams != 1 || nresults > 1 || arg1.kind == IrOpKind::Constant)
+        return {BuiltinImplType::None, -1};
+
+    build.loadAndCheckTag(arg1, LUA_TVECTOR, build.vmExit(pcpos));
+
+    IrOp x = build.inst(IrCmd::LOAD_FLOAT, arg1, build.constInt(0));
+    IrOp y = build.inst(IrCmd::LOAD_FLOAT, arg1, build.constInt(4));
+    IrOp z = build.inst(IrCmd::LOAD_FLOAT, arg1, build.constInt(8));
+
+    IrOp x2 = build.inst(IrCmd::MUL_NUM, x, x);
+    IrOp y2 = build.inst(IrCmd::MUL_NUM, y, y);
+    IrOp z2 = build.inst(IrCmd::MUL_NUM, z, z);
+
+    IrOp sum = build.inst(IrCmd::ADD_NUM, build.inst(IrCmd::ADD_NUM, x2, y2), z2);
+
+    IrOp mag = build.inst(IrCmd::SQRT_NUM, sum);
+
+    build.inst(IrCmd::STORE_DOUBLE, build.vmReg(ra), mag);
+    build.inst(IrCmd::STORE_TAG, build.vmReg(ra), build.constTag(LUA_TNUMBER));
+
+    return {BuiltinImplType::Full, 1};
+}
+
+static BuiltinImplResult translateBuiltinVectorNormalize(
+    IrBuilder& build,
+    int nparams,
+    int ra,
+    int arg,
+    IrOp args,
+    IrOp arg3,
+    int nresults,
+    int pcpos
+)
+{
+    LUAU_ASSERT(FFlag::LuauVectorLibNativeCodegen);
+
+    IrOp arg1 = build.vmReg(arg);
+
+    if (nparams != 1 || nresults > 1 || arg1.kind == IrOpKind::Constant)
+        return {BuiltinImplType::None, -1};
+
+    build.loadAndCheckTag(arg1, LUA_TVECTOR, build.vmExit(pcpos));
+
+    IrOp x = build.inst(IrCmd::LOAD_FLOAT, arg1, build.constInt(0));
+    IrOp y = build.inst(IrCmd::LOAD_FLOAT, arg1, build.constInt(4));
+    IrOp z = build.inst(IrCmd::LOAD_FLOAT, arg1, build.constInt(8));
+
+    IrOp x2 = build.inst(IrCmd::MUL_NUM, x, x);
+    IrOp y2 = build.inst(IrCmd::MUL_NUM, y, y);
+    IrOp z2 = build.inst(IrCmd::MUL_NUM, z, z);
+
+    IrOp sum = build.inst(IrCmd::ADD_NUM, build.inst(IrCmd::ADD_NUM, x2, y2), z2);
+
+    IrOp mag = build.inst(IrCmd::SQRT_NUM, sum);
+    IrOp inv = build.inst(IrCmd::DIV_NUM, build.constDouble(1.0), mag);
+
+    IrOp xr = build.inst(IrCmd::MUL_NUM, x, inv);
+    IrOp yr = build.inst(IrCmd::MUL_NUM, y, inv);
+    IrOp zr = build.inst(IrCmd::MUL_NUM, z, inv);
+
+    build.inst(IrCmd::STORE_VECTOR, build.vmReg(ra), xr, yr, zr);
+    build.inst(IrCmd::STORE_TAG, build.vmReg(ra), build.constTag(LUA_TVECTOR));
+
+    return {BuiltinImplType::Full, 1};
+}
+
+static BuiltinImplResult translateBuiltinVectorCross(IrBuilder& build, int nparams, int ra, int arg, IrOp args, IrOp arg3, int nresults, int pcpos)
+{
+    LUAU_ASSERT(FFlag::LuauVectorLibNativeCodegen);
+
+    IrOp arg1 = build.vmReg(arg);
+
+    if (nparams != 2 || nresults > 1 || arg1.kind == IrOpKind::Constant || args.kind == IrOpKind::Constant)
+        return {BuiltinImplType::None, -1};
+
+    build.loadAndCheckTag(arg1, LUA_TVECTOR, build.vmExit(pcpos));
+    build.loadAndCheckTag(args, LUA_TVECTOR, build.vmExit(pcpos));
+
+    IrOp x1 = build.inst(IrCmd::LOAD_FLOAT, arg1, build.constInt(0));
+    IrOp x2 = build.inst(IrCmd::LOAD_FLOAT, args, build.constInt(0));
+
+    IrOp y1 = build.inst(IrCmd::LOAD_FLOAT, arg1, build.constInt(4));
+    IrOp y2 = build.inst(IrCmd::LOAD_FLOAT, args, build.constInt(4));
+
+    IrOp z1 = build.inst(IrCmd::LOAD_FLOAT, arg1, build.constInt(8));
+    IrOp z2 = build.inst(IrCmd::LOAD_FLOAT, args, build.constInt(8));
+
+    IrOp y1z2 = build.inst(IrCmd::MUL_NUM, y1, z2);
+    IrOp z1y2 = build.inst(IrCmd::MUL_NUM, z1, y2);
+    IrOp xr = build.inst(IrCmd::SUB_NUM, y1z2, z1y2);
+
+    IrOp z1x2 = build.inst(IrCmd::MUL_NUM, z1, x2);
+    IrOp x1z2 = build.inst(IrCmd::MUL_NUM, x1, z2);
+    IrOp yr = build.inst(IrCmd::SUB_NUM, z1x2, x1z2);
+
+    IrOp x1y2 = build.inst(IrCmd::MUL_NUM, x1, y2);
+    IrOp y1x2 = build.inst(IrCmd::MUL_NUM, y1, x2);
+    IrOp zr = build.inst(IrCmd::SUB_NUM, x1y2, y1x2);
+
+    build.inst(IrCmd::STORE_VECTOR, build.vmReg(ra), xr, yr, zr);
+    build.inst(IrCmd::STORE_TAG, build.vmReg(ra), build.constTag(LUA_TVECTOR));
+
+    return {BuiltinImplType::Full, 1};
+}
+
+static BuiltinImplResult translateBuiltinVectorDot(IrBuilder& build, int nparams, int ra, int arg, IrOp args, IrOp arg3, int nresults, int pcpos)
+{
+    LUAU_ASSERT(FFlag::LuauVectorLibNativeCodegen);
+
+    IrOp arg1 = build.vmReg(arg);
+
+    if (nparams != 2 || nresults > 1 || arg1.kind == IrOpKind::Constant || args.kind == IrOpKind::Constant)
+        return {BuiltinImplType::None, -1};
+
+    build.loadAndCheckTag(arg1, LUA_TVECTOR, build.vmExit(pcpos));
+    build.loadAndCheckTag(args, LUA_TVECTOR, build.vmExit(pcpos));
+
+    IrOp x1 = build.inst(IrCmd::LOAD_FLOAT, arg1, build.constInt(0));
+    IrOp x2 = build.inst(IrCmd::LOAD_FLOAT, args, build.constInt(0));
+    IrOp xx = build.inst(IrCmd::MUL_NUM, x1, x2);
+
+    IrOp y1 = build.inst(IrCmd::LOAD_FLOAT, arg1, build.constInt(4));
+    IrOp y2 = build.inst(IrCmd::LOAD_FLOAT, args, build.constInt(4));
+    IrOp yy = build.inst(IrCmd::MUL_NUM, y1, y2);
+
+    IrOp z1 = build.inst(IrCmd::LOAD_FLOAT, arg1, build.constInt(8));
+    IrOp z2 = build.inst(IrCmd::LOAD_FLOAT, args, build.constInt(8));
+    IrOp zz = build.inst(IrCmd::MUL_NUM, z1, z2);
+
+    IrOp sum = build.inst(IrCmd::ADD_NUM, build.inst(IrCmd::ADD_NUM, xx, yy), zz);
+
+    build.inst(IrCmd::STORE_DOUBLE, build.vmReg(ra), sum);
+    build.inst(IrCmd::STORE_TAG, build.vmReg(ra), build.constTag(LUA_TNUMBER));
+
+    return {BuiltinImplType::Full, 1};
+}
+
+static BuiltinImplResult translateBuiltinVectorMap1(
+    IrBuilder& build,
+    IrCmd cmd,
+    int nparams,
+    int ra,
+    int arg,
+    IrOp args,
+    IrOp arg3,
+    int nresults,
+    int pcpos
+)
+{
+    LUAU_ASSERT(FFlag::LuauVectorLibNativeCodegen);
+
+    IrOp arg1 = build.vmReg(arg);
+
+    if (nparams != 1 || nresults > 1 || arg1.kind == IrOpKind::Constant)
+        return {BuiltinImplType::None, -1};
+
+    build.loadAndCheckTag(arg1, LUA_TVECTOR, build.vmExit(pcpos));
+
+    IrOp x1 = build.inst(IrCmd::LOAD_FLOAT, arg1, build.constInt(0));
+    IrOp y1 = build.inst(IrCmd::LOAD_FLOAT, arg1, build.constInt(4));
+    IrOp z1 = build.inst(IrCmd::LOAD_FLOAT, arg1, build.constInt(8));
+
+    IrOp xr = build.inst(cmd, x1);
+    IrOp yr = build.inst(cmd, y1);
+    IrOp zr = build.inst(cmd, z1);
+
+    build.inst(IrCmd::STORE_VECTOR, build.vmReg(ra), xr, yr, zr);
+    build.inst(IrCmd::STORE_TAG, build.vmReg(ra), build.constTag(LUA_TVECTOR));
+
+    return {BuiltinImplType::Full, 1};
+}
+
+static BuiltinImplResult translateBuiltinVectorClamp(
+    IrBuilder& build,
+    int nparams,
+    int ra,
+    int arg,
+    IrOp args,
+    IrOp arg3,
+    int nresults,
+    IrOp fallback,
+    int pcpos
+)
+{
+    LUAU_ASSERT(FFlag::LuauVectorLibNativeCodegen);
+
+    IrOp arg1 = build.vmReg(arg);
+
+    if (nparams != 3 || nresults > 1 || arg1.kind == IrOpKind::Constant || args.kind == IrOpKind::Constant || arg3.kind == IrOpKind::Constant)
+        return {BuiltinImplType::None, -1};
+
+    build.loadAndCheckTag(arg1, LUA_TVECTOR, build.vmExit(pcpos));
+    build.loadAndCheckTag(args, LUA_TVECTOR, build.vmExit(pcpos));
+    build.loadAndCheckTag(arg3, LUA_TVECTOR, build.vmExit(pcpos));
+
+    IrOp block1 = build.block(IrBlockKind::Internal);
+    IrOp block2 = build.block(IrBlockKind::Internal);
+    IrOp block3 = build.block(IrBlockKind::Internal);
+
+    IrOp x = build.inst(IrCmd::LOAD_FLOAT, arg1, build.constInt(0));
+    IrOp xmin = build.inst(IrCmd::LOAD_FLOAT, args, build.constInt(0));
+    IrOp xmax = build.inst(IrCmd::LOAD_FLOAT, arg3, build.constInt(0));
+
+    build.inst(IrCmd::JUMP_CMP_NUM, xmin, xmax, build.cond(IrCondition::NotLessEqual), fallback, block1);
+
+    build.beginBlock(block1);
+
+    IrOp y = build.inst(IrCmd::LOAD_FLOAT, arg1, build.constInt(4));
+    IrOp ymin = build.inst(IrCmd::LOAD_FLOAT, args, build.constInt(4));
+    IrOp ymax = build.inst(IrCmd::LOAD_FLOAT, arg3, build.constInt(4));
+
+    build.inst(IrCmd::JUMP_CMP_NUM, ymin, ymax, build.cond(IrCondition::NotLessEqual), fallback, block2);
+
+    build.beginBlock(block2);
+
+    IrOp z = build.inst(IrCmd::LOAD_FLOAT, arg1, build.constInt(8));
+    IrOp zmin = build.inst(IrCmd::LOAD_FLOAT, args, build.constInt(8));
+    IrOp zmax = build.inst(IrCmd::LOAD_FLOAT, arg3, build.constInt(8));
+
+    build.inst(IrCmd::JUMP_CMP_NUM, zmin, zmax, build.cond(IrCondition::NotLessEqual), fallback, block3);
+
+    build.beginBlock(block3);
+
+    IrOp xtemp = build.inst(IrCmd::MAX_NUM, xmin, x);
+    IrOp xclamped = build.inst(IrCmd::MIN_NUM, xmax, xtemp);
+
+    IrOp ytemp = build.inst(IrCmd::MAX_NUM, ymin, y);
+    IrOp yclamped = build.inst(IrCmd::MIN_NUM, ymax, ytemp);
+
+    IrOp ztemp = build.inst(IrCmd::MAX_NUM, zmin, z);
+    IrOp zclamped = build.inst(IrCmd::MIN_NUM, zmax, ztemp);
+
+    build.inst(IrCmd::STORE_VECTOR, build.vmReg(ra), xclamped, yclamped, zclamped);
+    build.inst(IrCmd::STORE_TAG, build.vmReg(ra), build.constTag(LUA_TVECTOR));
+
+    return {BuiltinImplType::UsesFallback, 1};
+}
+
+static BuiltinImplResult translateBuiltinVectorMap2(
+    IrBuilder& build,
+    IrCmd cmd,
+    int nparams,
+    int ra,
+    int arg,
+    IrOp args,
+    IrOp arg3,
+    int nresults,
+    int pcpos
+)
+{
+    LUAU_ASSERT(FFlag::LuauVectorLibNativeCodegen);
+
+    IrOp arg1 = build.vmReg(arg);
+
+    if (nparams != 2 || nresults > 1 || arg1.kind == IrOpKind::Constant || args.kind == IrOpKind::Constant)
+        return {BuiltinImplType::None, -1};
+
+    build.loadAndCheckTag(arg1, LUA_TVECTOR, build.vmExit(pcpos));
+    build.loadAndCheckTag(args, LUA_TVECTOR, build.vmExit(pcpos));
+
+    IrOp x1 = build.inst(IrCmd::LOAD_FLOAT, arg1, build.constInt(0));
+    IrOp y1 = build.inst(IrCmd::LOAD_FLOAT, arg1, build.constInt(4));
+    IrOp z1 = build.inst(IrCmd::LOAD_FLOAT, arg1, build.constInt(8));
+
+    IrOp x2 = build.inst(IrCmd::LOAD_FLOAT, args, build.constInt(0));
+    IrOp y2 = build.inst(IrCmd::LOAD_FLOAT, args, build.constInt(4));
+    IrOp z2 = build.inst(IrCmd::LOAD_FLOAT, args, build.constInt(8));
+
+    IrOp xr = build.inst(cmd, x1, x2);
+    IrOp yr = build.inst(cmd, y1, y2);
+    IrOp zr = build.inst(cmd, z1, z2);
+
+    build.inst(IrCmd::STORE_VECTOR, build.vmReg(ra), xr, yr, zr);
+    build.inst(IrCmd::STORE_TAG, build.vmReg(ra), build.constTag(LUA_TVECTOR));
+
+    return {BuiltinImplType::Full, 1};
+}
+
+
 BuiltinImplResult translateBuiltin(
     IrBuilder& build,
     int bfid,
@@ -898,6 +1194,8 @@ BuiltinImplResult translateBuiltin(
     int pcpos
 )
 {
+    BuiltinImplResult noneResult = {BuiltinImplType::None, -1};
+
     // Builtins are not allowed to handle variadic arguments
     if (nparams == LUA_MULTRET)
         return {BuiltinImplType::None, -1};
@@ -1018,6 +1316,35 @@ BuiltinImplResult translateBuiltin(
         return translateBuiltinBufferRead(build, nparams, ra, arg, args, arg3, nresults, pcpos, IrCmd::BUFFER_READF64, 8, IrCmd::NOP);
     case LBF_BUFFER_WRITEF64:
         return translateBuiltinBufferWrite(build, nparams, ra, arg, args, arg3, nresults, pcpos, IrCmd::BUFFER_WRITEF64, 8, IrCmd::NOP);
+    case LBF_VECTOR_MAGNITUDE:
+        return FFlag::LuauVectorLibNativeCodegen ? translateBuiltinVectorMagnitude(build, nparams, ra, arg, args, arg3, nresults, pcpos) : noneResult;
+    case LBF_VECTOR_NORMALIZE:
+        return FFlag::LuauVectorLibNativeCodegen ? translateBuiltinVectorNormalize(build, nparams, ra, arg, args, arg3, nresults, pcpos) : noneResult;
+    case LBF_VECTOR_CROSS:
+        return FFlag::LuauVectorLibNativeCodegen ? translateBuiltinVectorCross(build, nparams, ra, arg, args, arg3, nresults, pcpos) : noneResult;
+    case LBF_VECTOR_DOT:
+        return FFlag::LuauVectorLibNativeCodegen ? translateBuiltinVectorDot(build, nparams, ra, arg, args, arg3, nresults, pcpos) : noneResult;
+    case LBF_VECTOR_FLOOR:
+        return FFlag::LuauVectorLibNativeCodegen ? translateBuiltinVectorMap1(build, IrCmd::FLOOR_NUM, nparams, ra, arg, args, arg3, nresults, pcpos)
+                                                 : noneResult;
+    case LBF_VECTOR_CEIL:
+        return FFlag::LuauVectorLibNativeCodegen ? translateBuiltinVectorMap1(build, IrCmd::CEIL_NUM, nparams, ra, arg, args, arg3, nresults, pcpos)
+                                                 : noneResult;
+    case LBF_VECTOR_ABS:
+        return FFlag::LuauVectorLibNativeCodegen ? translateBuiltinVectorMap1(build, IrCmd::ABS_NUM, nparams, ra, arg, args, arg3, nresults, pcpos)
+                                                 : noneResult;
+    case LBF_VECTOR_SIGN:
+        return FFlag::LuauVectorLibNativeCodegen ? translateBuiltinVectorMap1(build, IrCmd::SIGN_NUM, nparams, ra, arg, args, arg3, nresults, pcpos)
+                                                 : noneResult;
+    case LBF_VECTOR_CLAMP:
+        return FFlag::LuauVectorLibNativeCodegen ? translateBuiltinVectorClamp(build, nparams, ra, arg, args, arg3, nresults, fallback, pcpos)
+                                                 : noneResult;
+    case LBF_VECTOR_MIN:
+        return FFlag::LuauVectorLibNativeCodegen ? translateBuiltinVectorMap2(build, IrCmd::MIN_NUM, nparams, ra, arg, args, arg3, nresults, pcpos)
+                                                 : noneResult;
+    case LBF_VECTOR_MAX:
+        return FFlag::LuauVectorLibNativeCodegen ? translateBuiltinVectorMap2(build, IrCmd::MAX_NUM, nparams, ra, arg, args, arg3, nresults, pcpos)
+                                                 : noneResult;
     default:
         return {BuiltinImplType::None, -1};
     }

CodeGen/src/OptimizeConstProp.cpp

@@ -17,7 +17,7 @@
 LUAU_FASTINTVARIABLE(LuauCodeGenMinLinearBlockPath, 3)
 LUAU_FASTINTVARIABLE(LuauCodeGenReuseSlotLimit, 64)
 LUAU_FASTINTVARIABLE(LuauCodeGenReuseUdataTagLimit, 64)
-LUAU_FASTFLAGVARIABLE(DebugLuauAbortingChecks, false)
+LUAU_FASTFLAGVARIABLE(DebugLuauAbortingChecks)
 
 namespace Luau
 {
@@ -536,6 +536,17 @@ static void handleBuiltinEffects(ConstPropState& state, LuauBuiltinFunction bfid
     case LBF_BUFFER_WRITEF32:
     case LBF_BUFFER_READF64:
     case LBF_BUFFER_WRITEF64:
+    case LBF_VECTOR_MAGNITUDE:
+    case LBF_VECTOR_NORMALIZE:
+    case LBF_VECTOR_CROSS:
+    case LBF_VECTOR_DOT:
+    case LBF_VECTOR_FLOOR:
+    case LBF_VECTOR_CEIL:
+    case LBF_VECTOR_ABS:
+    case LBF_VECTOR_SIGN:
+    case LBF_VECTOR_CLAMP:
+    case LBF_VECTOR_MIN:
+    case LBF_VECTOR_MAX:
         break;
     case LBF_TABLE_INSERT:
         state.invalidateHeap();

Common/include/Luau/Bytecode.h

@@ -600,6 +600,19 @@ enum LuauBuiltinFunction
     LBF_BUFFER_WRITEF32,
     LBF_BUFFER_READF64,
     LBF_BUFFER_WRITEF64,
+
+    // vector.
+    LBF_VECTOR_MAGNITUDE,
+    LBF_VECTOR_NORMALIZE,
+    LBF_VECTOR_CROSS,
+    LBF_VECTOR_DOT,
+    LBF_VECTOR_FLOOR,
+    LBF_VECTOR_CEIL,
+    LBF_VECTOR_ABS,
+    LBF_VECTOR_SIGN,
+    LBF_VECTOR_CLAMP,
+    LBF_VECTOR_MIN,
+    LBF_VECTOR_MAX,
 };
 
 // Capture type, used in LOP_CAPTURE

Common/include/Luau/Common.h

@@ -106,10 +106,10 @@ FValue<T>* FValue<T>::list = nullptr;
     { \
     extern Luau::FValue<bool> flag; \
     }
-#define LUAU_FASTFLAGVARIABLE(flag, def) \
+#define LUAU_FASTFLAGVARIABLE(flag) \
     namespace FFlag \
     { \
-    Luau::FValue<bool> flag(#flag, def, false); \
+    Luau::FValue<bool> flag(#flag, false, false); \
     }
 #define LUAU_FASTINT(flag) \
     namespace FInt \

Compiler/include/Luau/Compiler.h

@@ -37,11 +37,11 @@ struct CompileOptions
     // 2 - statement and expression coverage (verbose)
     int coverageLevel = 0;
 
-    // global builtin to construct vectors; disabled by default
+    // alternative global builtin to construct vectors, in addition to default builtin 'vector.create'
     const char* vectorLib = nullptr;
     const char* vectorCtor = nullptr;
 
-    // vector type name for type tables; disabled by default
+    // alternative vector type name for type tables, in addition to default type 'vector'
     const char* vectorType = nullptr;
 
     // null-terminated array of globals that are mutable; disables the import optimization for fields accessed through these

Compiler/include/luacode.h

@@ -33,11 +33,11 @@ struct lua_CompileOptions
     // 2 - statement and expression coverage (verbose)
     int coverageLevel; // default=0
 
-    // global builtin to construct vectors; disabled by default
+    // alternative global builtin to construct vectors, in addition to default builtin 'vector.create'
     const char* vectorLib;
     const char* vectorCtor;
 
-    // vector type name for type tables; disabled by default
+    // alternative vector type name for type tables, in addition to default type 'vector'
     const char* vectorType;
 
     // null-terminated array of globals that are mutable; disables the import optimization for fields accessed through these

Compiler/src/Builtins.cpp

@@ -4,6 +4,8 @@
 #include "Luau/Bytecode.h"
 #include "Luau/Compiler.h"
 
+LUAU_FASTFLAGVARIABLE(LuauVectorBuiltins)
+
 namespace Luau
 {
 namespace Compile
@@ -220,6 +222,34 @@ static int getBuiltinFunctionId(const Builtin& builtin, const CompileOptions& op
             return LBF_BUFFER_WRITEF64;
     }
 
+    if (FFlag::LuauVectorBuiltins && builtin.object == "vector")
+    {
+        if (builtin.method == "create")
+            return LBF_VECTOR;
+        if (builtin.method == "magnitude")
+            return LBF_VECTOR_MAGNITUDE;
+        if (builtin.method == "normalize")
+            return LBF_VECTOR_NORMALIZE;
+        if (builtin.method == "cross")
+            return LBF_VECTOR_CROSS;
+        if (builtin.method == "dot")
+            return LBF_VECTOR_DOT;
+        if (builtin.method == "floor")
+            return LBF_VECTOR_FLOOR;
+        if (builtin.method == "ceil")
+            return LBF_VECTOR_CEIL;
+        if (builtin.method == "abs")
+            return LBF_VECTOR_ABS;
+        if (builtin.method == "sign")
+            return LBF_VECTOR_SIGN;
+        if (builtin.method == "clamp")
+            return LBF_VECTOR_CLAMP;
+        if (builtin.method == "min")
+            return LBF_VECTOR_MIN;
+        if (builtin.method == "max")
+            return LBF_VECTOR_MAX;
+    }
+
     if (options.vectorCtor)
     {
         if (options.vectorLib)
@@ -463,6 +493,23 @@ BuiltinInfo getBuiltinInfo(int bfid)
     case LBF_BUFFER_WRITEF32:
     case LBF_BUFFER_WRITEF64:
         return {3, 0, BuiltinInfo::Flag_NoneSafe};
+
+    case LBF_VECTOR_MAGNITUDE:
+    case LBF_VECTOR_NORMALIZE:
+        return {1, 1, BuiltinInfo::Flag_NoneSafe};
+    case LBF_VECTOR_CROSS:
+    case LBF_VECTOR_DOT:
+        return {2, 1, BuiltinInfo::Flag_NoneSafe};
+    case LBF_VECTOR_FLOOR:
+    case LBF_VECTOR_CEIL:
+    case LBF_VECTOR_ABS:
+    case LBF_VECTOR_SIGN:
+        return {1, 1, BuiltinInfo::Flag_NoneSafe};
+    case LBF_VECTOR_CLAMP:
+        return {3, 1, BuiltinInfo::Flag_NoneSafe};
+    case LBF_VECTOR_MIN:
+    case LBF_VECTOR_MAX:
+        return {-1, 1}; // variadic
     }
 
     LUAU_UNREACHABLE();

Compiler/src/Types.cpp

@@ -3,6 +3,8 @@
 
 #include "Luau/BytecodeBuilder.h"
 
+LUAU_FASTFLAGVARIABLE(LuauCompileVectorTypeInfo)
+
 namespace Luau
 {
 
@@ -29,6 +31,8 @@ static LuauBytecodeType getPrimitiveType(AstName name)
         return LBC_TYPE_THREAD;
     else if (name == "buffer")
         return LBC_TYPE_BUFFER;
+    else if (FFlag::LuauCompileVectorTypeInfo && name == "vector")
+        return LBC_TYPE_VECTOR;
     else if (name == "any" || name == "unknown")
         return LBC_TYPE_ANY;
     else
@@ -40,7 +44,7 @@ static LuauBytecodeType getType(
     const AstArray<AstGenericType>& generics,
     const DenseHashMap<AstName, AstStatTypeAlias*>& typeAliases,
     bool resolveAliases,
-    const char* vectorType,
+    const char* hostVectorType,
     const DenseHashMap<AstName, uint8_t>& userdataTypes,
     BytecodeBuilder& bytecode
 )
@@ -54,7 +58,7 @@ static LuauBytecodeType getType(
         {
             // note: we only resolve aliases to the depth of 1 to avoid dealing with recursive aliases
             if (resolveAliases)
-                return getType((*alias)->type, (*alias)->generics, typeAliases, /* resolveAliases= */ false, vectorType, userdataTypes, bytecode);
+                return getType((*alias)->type, (*alias)->generics, typeAliases, /* resolveAliases= */ false, hostVectorType, userdataTypes, bytecode);
             else
                 return LBC_TYPE_ANY;
         }
@@ -62,7 +66,7 @@ static LuauBytecodeType getType(
         if (isGeneric(ref->name, generics))
             return LBC_TYPE_ANY;
 
-        if (vectorType && ref->name == vectorType)
+        if (hostVectorType && ref->name == hostVectorType)
             return LBC_TYPE_VECTOR;
 
         if (LuauBytecodeType prim = getPrimitiveType(ref->name); prim != LBC_TYPE_INVALID)
@@ -92,7 +96,7 @@ static LuauBytecodeType getType(
 
         for (AstType* ty : un->types)
         {
-            LuauBytecodeType et = getType(ty, generics, typeAliases, resolveAliases, vectorType, userdataTypes, bytecode);
+            LuauBytecodeType et = getType(ty, generics, typeAliases, resolveAliases, hostVectorType, userdataTypes, bytecode);
 
             if (et == LBC_TYPE_NIL)
             {
@@ -126,7 +130,7 @@ static LuauBytecodeType getType(
 static std::string getFunctionType(
     const AstExprFunction* func,
     const DenseHashMap<AstName, AstStatTypeAlias*>& typeAliases,
-    const char* vectorType,
+    const char* hostVectorType,
     const DenseHashMap<AstName, uint8_t>& userdataTypes,
     BytecodeBuilder& bytecode
 )
@@ -146,8 +150,9 @@ static std::string getFunctionType(
     for (AstLocal* arg : func->args)
     {
         LuauBytecodeType ty =
-            arg->annotation ? getType(arg->annotation, func->generics, typeAliases, /* resolveAliases= */ true, vectorType, userdataTypes, bytecode)
-                            : LBC_TYPE_ANY;
+            arg->annotation
+                ? getType(arg->annotation, func->generics, typeAliases, /* resolveAliases= */ true, hostVectorType, userdataTypes, bytecode)
+                : LBC_TYPE_ANY;
 
         if (ty != LBC_TYPE_ANY)
             haveNonAnyParam = true;
@@ -175,7 +180,7 @@ struct TypeMapVisitor : AstVisitor
     DenseHashMap<AstExprFunction*, std::string>& functionTypes;
     DenseHashMap<AstLocal*, LuauBytecodeType>& localTypes;
     DenseHashMap<AstExpr*, LuauBytecodeType>& exprTypes;
-    const char* vectorType;
+    const char* hostVectorType;
     const DenseHashMap<AstName, uint8_t>& userdataTypes;
     const BuiltinAstTypes& builtinTypes;
     const DenseHashMap<AstExprCall*, int>& builtinCalls;
@@ -191,7 +196,7 @@ struct TypeMapVisitor : AstVisitor
         DenseHashMap<AstExprFunction*, std::string>& functionTypes,
         DenseHashMap<AstLocal*, LuauBytecodeType>& localTypes,
         DenseHashMap<AstExpr*, LuauBytecodeType>& exprTypes,
-        const char* vectorType,
+        const char* hostVectorType,
         const DenseHashMap<AstName, uint8_t>& userdataTypes,
         const BuiltinAstTypes& builtinTypes,
         const DenseHashMap<AstExprCall*, int>& builtinCalls,
@@ -201,7 +206,7 @@ struct TypeMapVisitor : AstVisitor
         : functionTypes(functionTypes)
         , localTypes(localTypes)
         , exprTypes(exprTypes)
-        , vectorType(vectorType)
+        , hostVectorType(hostVectorType)
         , userdataTypes(userdataTypes)
         , builtinTypes(builtinTypes)
         , builtinCalls(builtinCalls)
@@ -271,7 +276,7 @@ struct TypeMapVisitor : AstVisitor
 
         resolvedExprs[expr] = ty;
 
-        LuauBytecodeType bty = getType(ty, {}, typeAliases, /* resolveAliases= */ true, vectorType, userdataTypes, bytecode);
+        LuauBytecodeType bty = getType(ty, {}, typeAliases, /* resolveAliases= */ true, hostVectorType, userdataTypes, bytecode);
         exprTypes[expr] = bty;
         return bty;
     }
@@ -282,7 +287,7 @@ struct TypeMapVisitor : AstVisitor
 
         resolvedLocals[local] = ty;
 
-        LuauBytecodeType bty = getType(ty, {}, typeAliases, /* resolveAliases= */ true, vectorType, userdataTypes, bytecode);
+        LuauBytecodeType bty = getType(ty, {}, typeAliases, /* resolveAliases= */ true, hostVectorType, userdataTypes, bytecode);
 
         if (bty != LBC_TYPE_ANY)
             localTypes[local] = bty;
@@ -370,7 +375,7 @@ struct TypeMapVisitor : AstVisitor
 
     bool visit(AstExprFunction* node) override
     {
-        std::string type = getFunctionType(node, typeAliases, vectorType, userdataTypes, bytecode);
+        std::string type = getFunctionType(node, typeAliases, hostVectorType, userdataTypes, bytecode);
 
         if (!type.empty())
             functionTypes[node] = std::move(type);
@@ -675,6 +680,8 @@ struct TypeMapVisitor : AstVisitor
             case LBF_BUFFER_READU32:
             case LBF_BUFFER_READF32:
             case LBF_BUFFER_READF64:
+            case LBF_VECTOR_MAGNITUDE:
+            case LBF_VECTOR_DOT:
                 recordResolvedType(node, &builtinTypes.numberType);
                 break;
 
@@ -691,6 +698,15 @@ struct TypeMapVisitor : AstVisitor
                 break;
 
             case LBF_VECTOR:
+            case LBF_VECTOR_NORMALIZE:
+            case LBF_VECTOR_CROSS:
+            case LBF_VECTOR_FLOOR:
+            case LBF_VECTOR_CEIL:
+            case LBF_VECTOR_ABS:
+            case LBF_VECTOR_SIGN:
+            case LBF_VECTOR_CLAMP:
+            case LBF_VECTOR_MIN:
+            case LBF_VECTOR_MAX:
                 recordResolvedType(node, &builtinTypes.vectorType);
                 break;
             }
@@ -712,7 +728,7 @@ void buildTypeMap(
     DenseHashMap<AstLocal*, LuauBytecodeType>& localTypes,
     DenseHashMap<AstExpr*, LuauBytecodeType>& exprTypes,
     AstNode* root,
-    const char* vectorType,
+    const char* hostVectorType,
     const DenseHashMap<AstName, uint8_t>& userdataTypes,
     const BuiltinAstTypes& builtinTypes,
     const DenseHashMap<AstExprCall*, int>& builtinCalls,
@@ -720,7 +736,7 @@ void buildTypeMap(
     BytecodeBuilder& bytecode
 )
 {
-    TypeMapVisitor visitor(functionTypes, localTypes, exprTypes, vectorType, userdataTypes, builtinTypes, builtinCalls, globals, bytecode);
+    TypeMapVisitor visitor(functionTypes, localTypes, exprTypes, hostVectorType, userdataTypes, builtinTypes, builtinCalls, globals, bytecode);
     root->visit(&visitor);
 }
 

Compiler/src/Types.h

@@ -14,8 +14,8 @@ class BytecodeBuilder;
 
 struct BuiltinAstTypes
 {
-    BuiltinAstTypes(const char* vectorType)
-        : vectorType{{}, std::nullopt, AstName{vectorType}, std::nullopt, {}}
+    BuiltinAstTypes(const char* hostVectorType)
+        : hostVectorType{{}, std::nullopt, AstName{hostVectorType}, std::nullopt, {}}
     {
     }
 
@@ -23,7 +23,9 @@ struct BuiltinAstTypes
     AstTypeReference booleanType{{}, std::nullopt, AstName{"boolean"}, std::nullopt, {}};
     AstTypeReference numberType{{}, std::nullopt, AstName{"number"}, std::nullopt, {}};
     AstTypeReference stringType{{}, std::nullopt, AstName{"string"}, std::nullopt, {}};
-    AstTypeReference vectorType;
+    AstTypeReference vectorType{{}, std::nullopt, AstName{"vector"}, std::nullopt, {}};
+
+    AstTypeReference hostVectorType;
 };
 
 void buildTypeMap(
@@ -31,7 +33,7 @@ void buildTypeMap(
     DenseHashMap<AstLocal*, LuauBytecodeType>& localTypes,
     DenseHashMap<AstExpr*, LuauBytecodeType>& exprTypes,
     AstNode* root,
-    const char* vectorType,
+    const char* hostVectorType,
     const DenseHashMap<AstName, uint8_t>& userdataTypes,
     const BuiltinAstTypes& builtinTypes,
     const DenseHashMap<AstExprCall*, int>& builtinCalls,

Sources.cmake

@@ -351,6 +351,7 @@ target_sources(Luau.VM PRIVATE
     VM/src/ltm.cpp
     VM/src/ludata.cpp
     VM/src/lutf8lib.cpp
+    VM/src/lveclib.cpp
     VM/src/lvmexecute.cpp
     VM/src/lvmload.cpp
     VM/src/lvmutils.cpp

VM/include/lua.h

@@ -189,6 +189,7 @@ LUA_API int lua_pushthread(lua_State* L);
 
 LUA_API void lua_pushlightuserdatatagged(lua_State* L, void* p, int tag);
 LUA_API void* lua_newuserdatatagged(lua_State* L, size_t sz, int tag);
+LUA_API void* lua_newuserdatataggedwithmetatable(lua_State* L, size_t sz, int tag); // metatable fetched with lua_getuserdatametatable
 LUA_API void* lua_newuserdatadtor(lua_State* L, size_t sz, void (*dtor)(void*));
 
 LUA_API void* lua_newbuffer(lua_State* L, size_t sz);

VM/include/lualib.h

@@ -136,6 +136,9 @@ LUALIB_API int luaopen_math(lua_State* L);
 #define LUA_DBLIBNAME "debug"
 LUALIB_API int luaopen_debug(lua_State* L);
 
+#define LUA_VECLIBNAME "vector"
+LUALIB_API int luaopen_vector(lua_State* L);
+
 // open all builtin libraries
 LUALIB_API void luaL_openlibs(lua_State* L);
 

VM/src/lapi.cpp

@@ -1283,6 +1283,26 @@ void* lua_newuserdatatagged(lua_State* L, size_t sz, int tag)
     return u->data;
 }
 
+void* lua_newuserdatataggedwithmetatable(lua_State* L, size_t sz, int tag)
+{
+    api_check(L, unsigned(tag) < LUA_UTAG_LIMIT);
+    luaC_checkGC(L);
+    luaC_threadbarrier(L);
+    Udata* u = luaU_newudata(L, sz, tag);
+
+    // currently, we always allocate unmarked objects, so forward barrier can be skipped
+    LUAU_ASSERT(!isblack(obj2gco(u)));
+
+    Table* h = L->global->udatamt[tag];
+    api_check(L, h != nullptr);
+
+    u->metatable = h;
+
+    setuvalue(L, L->top, u);
+    api_incr_top(L);
+    return u->data;
+}
+
 void* lua_newuserdatadtor(lua_State* L, size_t sz, void (*dtor)(void*))
 {
     luaC_checkGC(L);

VM/src/lbuiltins.cpp

@@ -1437,6 +1437,263 @@ static int luauF_writefp(lua_State* L, StkId res, TValue* arg0, int nresults, St
     return -1;
 }
 
+static int luauF_vectormagnitude(lua_State* L, StkId res, TValue* arg0, int nresults, StkId args, int nparams)
+{
+    if (nparams >= 1 && nresults <= 1 && ttisvector(arg0))
+    {
+        const float* v = vvalue(arg0);
+
+#if LUA_VECTOR_SIZE == 4
+        setnvalue(res, sqrtf(v[0] * v[0] + v[1] * v[1] + v[2] * v[2] + v[3] * v[3]));
+#else
+        setnvalue(res, sqrtf(v[0] * v[0] + v[1] * v[1] + v[2] * v[2]));
+#endif
+
+        return 1;
+    }
+
+    return -1;
+}
+
+static int luauF_vectornormalize(lua_State* L, StkId res, TValue* arg0, int nresults, StkId args, int nparams)
+{
+    if (nparams >= 1 && nresults <= 1 && ttisvector(arg0))
+    {
+        const float* v = vvalue(arg0);
+
+#if LUA_VECTOR_SIZE == 4
+        float invSqrt = 1.0f / sqrtf(v[0] * v[0] + v[1] * v[1] + v[2] * v[2] + v[3] * v[3]);
+
+        setvvalue(res, v[0] * invSqrt, v[1] * invSqrt, v[2] * invSqrt, v[3] * invSqrt);
+#else
+        float invSqrt = 1.0f / sqrtf(v[0] * v[0] + v[1] * v[1] + v[2] * v[2]);
+
+        setvvalue(res, v[0] * invSqrt, v[1] * invSqrt, v[2] * invSqrt, 0.0f);
+#endif
+
+        return 1;
+    }
+
+    return -1;
+}
+
+static int luauF_vectorcross(lua_State* L, StkId res, TValue* arg0, int nresults, StkId args, int nparams)
+{
+    if (nparams >= 2 && nresults <= 1 && ttisvector(arg0) && ttisvector(args))
+    {
+        const float* a = vvalue(arg0);
+        const float* b = vvalue(args);
+
+        // same for 3- and 4- wide vectors
+        setvvalue(res, a[1] * b[2] - a[2] * b[1], a[2] * b[0] - a[0] * b[2], a[0] * b[1] - a[1] * b[0], 0.0f);
+        return 1;
+    }
+
+    return -1;
+}
+
+static int luauF_vectordot(lua_State* L, StkId res, TValue* arg0, int nresults, StkId args, int nparams)
+{
+    if (nparams >= 2 && nresults <= 1 && ttisvector(arg0) && ttisvector(args))
+    {
+        const float* a = vvalue(arg0);
+        const float* b = vvalue(args);
+
+#if LUA_VECTOR_SIZE == 4
+        setnvalue(res, a[0] * b[0] + a[1] * b[1] + a[2] * b[2] + a[3] * b[3]);
+#else
+        setnvalue(res, a[0] * b[0] + a[1] * b[1] + a[2] * b[2]);
+#endif
+
+        return 1;
+    }
+
+    return -1;
+}
+
+static int luauF_vectorfloor(lua_State* L, StkId res, TValue* arg0, int nresults, StkId args, int nparams)
+{
+    if (nparams >= 1 && nresults <= 1 && ttisvector(arg0))
+    {
+        const float* v = vvalue(arg0);
+
+#if LUA_VECTOR_SIZE == 4
+        setvvalue(res, floorf(v[0]), floorf(v[1]), floorf(v[2]), floorf(v[3]));
+#else
+        setvvalue(res, floorf(v[0]), floorf(v[1]), floorf(v[2]), 0.0f);
+#endif
+
+        return 1;
+    }
+
+    return -1;
+}
+
+static int luauF_vectorceil(lua_State* L, StkId res, TValue* arg0, int nresults, StkId args, int nparams)
+{
+    if (nparams >= 1 && nresults <= 1 && ttisvector(arg0))
+    {
+        const float* v = vvalue(arg0);
+
+#if LUA_VECTOR_SIZE == 4
+        setvvalue(res, ceilf(v[0]), ceilf(v[1]), ceilf(v[2]), ceilf(v[3]));
+#else
+        setvvalue(res, ceilf(v[0]), ceilf(v[1]), ceilf(v[2]), 0.0f);
+#endif
+
+        return 1;
+    }
+
+    return -1;
+}
+
+static int luauF_vectorabs(lua_State* L, StkId res, TValue* arg0, int nresults, StkId args, int nparams)
+{
+    if (nparams >= 1 && nresults <= 1 && ttisvector(arg0))
+    {
+        const float* v = vvalue(arg0);
+
+#if LUA_VECTOR_SIZE == 4
+        setvvalue(res, fabsf(v[0]), fabsf(v[1]), fabsf(v[2]), fabsf(v[3]));
+#else
+        setvvalue(res, fabsf(v[0]), fabsf(v[1]), fabsf(v[2]), 0.0f);
+#endif
+
+        return 1;
+    }
+
+    return -1;
+}
+
+static int luauF_vectorsign(lua_State* L, StkId res, TValue* arg0, int nresults, StkId args, int nparams)
+{
+    if (nparams >= 1 && nresults <= 1 && ttisvector(arg0))
+    {
+        const float* v = vvalue(arg0);
+
+#if LUA_VECTOR_SIZE == 4
+        setvvalue(res, luaui_signf(v[0]), luaui_signf(v[1]), luaui_signf(v[2]), luaui_signf(v[3]));
+#else
+        setvvalue(res, luaui_signf(v[0]), luaui_signf(v[1]), luaui_signf(v[2]), 0.0f);
+#endif
+
+        return 1;
+    }
+
+    return -1;
+}
+
+static int luauF_vectorclamp(lua_State* L, StkId res, TValue* arg0, int nresults, StkId args, int nparams)
+{
+    if (nparams >= 3 && nresults <= 1 && ttisvector(arg0) && ttisvector(args) && ttisvector(args + 1))
+    {
+        const float* v = vvalue(arg0);
+        const float* min = vvalue(args);
+        const float* max = vvalue(args + 1);
+
+        if (min[0] <= max[0] && min[1] <= max[1] && min[2] <= max[2])
+        {
+#if LUA_VECTOR_SIZE == 4
+            setvvalue(
+                res,
+                luaui_clampf(v[0], min[0], max[0]),
+                luaui_clampf(v[1], min[1], max[1]),
+                luaui_clampf(v[2], min[2], max[2]),
+                luaui_clampf(v[3], min[3], max[3])
+            );
+#else
+            setvvalue(res, luaui_clampf(v[0], min[0], max[0]), luaui_clampf(v[1], min[1], max[1]), luaui_clampf(v[2], min[2], max[2]), 0.0f);
+#endif
+
+            return 1;
+        }
+    }
+
+    return -1;
+}
+
+static int luauF_vectormin(lua_State* L, StkId res, TValue* arg0, int nresults, StkId args, int nparams)
+{
+    if (nparams >= 2 && nresults <= 1 && ttisvector(arg0) && ttisvector(args))
+    {
+        const float* a = vvalue(arg0);
+        const float* b = vvalue(args);
+
+        float result[4];
+
+        result[0] = (b[0] < a[0]) ? b[0] : a[0];
+        result[1] = (b[1] < a[1]) ? b[1] : a[1];
+        result[2] = (b[2] < a[2]) ? b[2] : a[2];
+
+#if LUA_VECTOR_SIZE == 4
+        result[3] = (b[3] < a[3]) ? b[3] : a[3];
+#else
+        result[3] = 0.0f;
+#endif
+
+        for (int i = 3; i <= nparams; ++i)
+        {
+            if (!ttisvector(args + (i - 2)))
+                return -1;
+
+            const float* c = vvalue(args + (i - 2));
+
+            result[0] = (c[0] < result[0]) ? c[0] : result[0];
+            result[1] = (c[1] < result[1]) ? c[1] : result[1];
+            result[2] = (c[2] < result[2]) ? c[2] : result[2];
+#if LUA_VECTOR_SIZE == 4
+            result[3] = (c[3] < result[3]) ? c[3] : result[3];
+#endif
+        }
+
+        setvvalue(res, result[0], result[1], result[2], result[3]);
+        return 1;
+    }
+
+    return -1;
+}
+
+static int luauF_vectormax(lua_State* L, StkId res, TValue* arg0, int nresults, StkId args, int nparams)
+{
+    if (nparams >= 2 && nresults <= 1 && ttisvector(arg0) && ttisvector(args))
+    {
+        const float* a = vvalue(arg0);
+        const float* b = vvalue(args);
+
+        float result[4];
+
+        result[0] = (b[0] > a[0]) ? b[0] : a[0];
+        result[1] = (b[1] > a[1]) ? b[1] : a[1];
+        result[2] = (b[2] > a[2]) ? b[2] : a[2];
+
+#if LUA_VECTOR_SIZE == 4
+        result[3] = (b[3] > a[3]) ? b[3] : a[3];
+#else
+        result[3] = 0.0f;
+#endif
+
+        for (int i = 3; i <= nparams; ++i)
+        {
+            if (!ttisvector(args + (i - 2)))
+                return -1;
+
+            const float* c = vvalue(args + (i - 2));
+
+            result[0] = (c[0] > result[0]) ? c[0] : result[0];
+            result[1] = (c[1] > result[1]) ? c[1] : result[1];
+            result[2] = (c[2] > result[2]) ? c[2] : result[2];
+#if LUA_VECTOR_SIZE == 4
+            result[3] = (c[3] > result[3]) ? c[3] : result[3];
+#endif
+        }
+
+        setvvalue(res, result[0], result[1], result[2], result[3]);
+        return 1;
+    }
+
+    return -1;
+}
+
 static int luauF_missing(lua_State* L, StkId res, TValue* arg0, int nresults, StkId args, int nparams)
 {
     return -1;
@@ -1620,6 +1877,18 @@ const luau_FastFunction luauF_table[256] = {
     luauF_readfp<double>,
     luauF_writefp<double>,
 
+    luauF_vectormagnitude,
+    luauF_vectornormalize,
+    luauF_vectorcross,
+    luauF_vectordot,
+    luauF_vectorfloor,
+    luauF_vectorceil,
+    luauF_vectorabs,
+    luauF_vectorsign,
+    luauF_vectorclamp,
+    luauF_vectormin,
+    luauF_vectormax,
+
 // When adding builtins, add them above this line; what follows is 64 "dummy" entries with luauF_missing fallback.
 // This is important so that older versions of the runtime that don't support newer builtins automatically fall back via luauF_missing.
 // Given the builtin addition velocity this should always provide a larger compatibility window than bytecode versions suggest.

VM/src/ldblib.cpp

@@ -8,6 +8,8 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+LUAU_DYNAMIC_FASTFLAGVARIABLE(LuauDebugInfoInvArgLeftovers, false)
+
 static lua_State* getthread(lua_State* L, int* arg)
 {
     if (lua_isthread(L, 1))
@@ -107,6 +109,10 @@ static int db_info(lua_State* L)
             break;
 
         default:
+            // restore stack state of another thread as 'f' option might not have been visited yet
+            if (DFFlag::LuauDebugInfoInvArgLeftovers && L != L1)
+                lua_settop(L1, l1top);
+
             luaL_argerror(L, arg + 2, "invalid option");
         }
     }

VM/src/linit.cpp

@@ -15,6 +15,7 @@ static const luaL_Reg lualibs[] = {
     {LUA_UTF8LIBNAME, luaopen_utf8},
     {LUA_BITLIBNAME, luaopen_bit32},
     {LUA_BUFFERLIBNAME, luaopen_buffer},
+    {LUA_VECLIBNAME, luaopen_vector},
     {NULL, NULL},
 };
 

VM/src/lmathlib.cpp

@@ -7,7 +7,7 @@
 #include <math.h>
 #include <time.h>
 
-LUAU_FASTFLAGVARIABLE(LuauMathMap, false)
+LUAU_FASTFLAGVARIABLE(LuauMathMap)
 
 #undef PI
 #define PI (3.14159265358979323846)

VM/src/lnumutils.h

@@ -33,6 +33,17 @@ inline bool luai_vecisnan(const float* a)
 #endif
 }
 
+inline float luaui_signf(float v)
+{
+    return v > 0.0f ? 1.0f : v < 0.0f ? -1.0f : 0.0f;
+}
+
+inline float luaui_clampf(float v, float min, float max)
+{
+    float r = v < min ? min : v;
+    return r > max ? max : r;
+}
+
 LUAU_FASTMATH_BEGIN
 inline double luai_nummod(double a, double b)
 {

VM/src/lveclib.cpp

@@ -0,0 +1,291 @@
+// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
+#include "lualib.h"
+
+#include "lcommon.h"
+#include "lnumutils.h"
+
+#include <math.h>
+
+static int vector_create(lua_State* L)
+{
+    double x = luaL_checknumber(L, 1);
+    double y = luaL_checknumber(L, 2);
+    double z = luaL_checknumber(L, 3);
+
+#if LUA_VECTOR_SIZE == 4
+    // checking argument count to avoid accepting 'nil' as a valid value
+    double w = lua_gettop(L) >= 4 ? luaL_checknumber(L, 4) : 0.0;
+
+    lua_pushvector(L, float(x), float(y), float(z), float(w));
+#else
+    lua_pushvector(L, float(x), float(y), float(z));
+#endif
+
+    return 1;
+}
+
+static int vector_magnitude(lua_State* L)
+{
+    const float* v = luaL_checkvector(L, 1);
+
+#if LUA_VECTOR_SIZE == 4
+    lua_pushnumber(L, sqrtf(v[0] * v[0] + v[1] * v[1] + v[2] * v[2] + v[3] * v[3]));
+#else
+    lua_pushnumber(L, sqrtf(v[0] * v[0] + v[1] * v[1] + v[2] * v[2]));
+#endif
+
+    return 1;
+}
+
+static int vector_normalize(lua_State* L)
+{
+    const float* v = luaL_checkvector(L, 1);
+
+#if LUA_VECTOR_SIZE == 4
+    float invSqrt = 1.0f / sqrtf(v[0] * v[0] + v[1] * v[1] + v[2] * v[2] + v[3] * v[3]);
+
+    lua_pushvector(L, v[0] * invSqrt, v[1] * invSqrt, v[2] * invSqrt, v[3] * invSqrt);
+#else
+    float invSqrt = 1.0f / sqrtf(v[0] * v[0] + v[1] * v[1] + v[2] * v[2]);
+
+    lua_pushvector(L, v[0] * invSqrt, v[1] * invSqrt, v[2] * invSqrt);
+#endif
+
+    return 1;
+}
+
+static int vector_cross(lua_State* L)
+{
+    const float* a = luaL_checkvector(L, 1);
+    const float* b = luaL_checkvector(L, 2);
+
+#if LUA_VECTOR_SIZE == 4
+    lua_pushvector(L, a[1] * b[2] - a[2] * b[1], a[2] * b[0] - a[0] * b[2], a[0] * b[1] - a[1] * b[0], 0.0f);
+#else
+    lua_pushvector(L, a[1] * b[2] - a[2] * b[1], a[2] * b[0] - a[0] * b[2], a[0] * b[1] - a[1] * b[0]);
+#endif
+
+    return 1;
+}
+
+static int vector_dot(lua_State* L)
+{
+    const float* a = luaL_checkvector(L, 1);
+    const float* b = luaL_checkvector(L, 2);
+
+#if LUA_VECTOR_SIZE == 4
+    lua_pushnumber(L, a[0] * b[0] + a[1] * b[1] + a[2] * b[2] + a[3] * b[3]);
+#else
+    lua_pushnumber(L, a[0] * b[0] + a[1] * b[1] + a[2] * b[2]);
+#endif
+
+    return 1;
+}
+
+static int vector_angle(lua_State* L)
+{
+    const float* a = luaL_checkvector(L, 1);
+    const float* b = luaL_checkvector(L, 2);
+    const float* axis = luaL_optvector(L, 3, nullptr);
+
+    // cross(a, b)
+    float cross[] = {a[1] * b[2] - a[2] * b[1], a[2] * b[0] - a[0] * b[2], a[0] * b[1] - a[1] * b[0]};
+
+    double sinA = sqrt(cross[0] * cross[0] + cross[1] * cross[1] + cross[2] * cross[2]);
+    double cosA = a[0] * b[0] + a[1] * b[1] + a[2] * b[2];
+    double angle = atan2(sinA, cosA);
+
+    if (axis)
+    {
+        if (cross[0] * axis[0] + cross[1] * axis[1] + cross[2] * axis[2] < 0.0f)
+            angle = -angle;
+    }
+
+    lua_pushnumber(L, angle);
+    return 1;
+}
+
+static int vector_floor(lua_State* L)
+{
+    const float* v = luaL_checkvector(L, 1);
+
+#if LUA_VECTOR_SIZE == 4
+    lua_pushvector(L, floorf(v[0]), floorf(v[1]), floorf(v[2]), floorf(v[3]));
+#else
+    lua_pushvector(L, floorf(v[0]), floorf(v[1]), floorf(v[2]));
+#endif
+
+    return 1;
+}
+
+static int vector_ceil(lua_State* L)
+{
+    const float* v = luaL_checkvector(L, 1);
+
+#if LUA_VECTOR_SIZE == 4
+    lua_pushvector(L, ceilf(v[0]), ceilf(v[1]), ceilf(v[2]), ceilf(v[3]));
+#else
+    lua_pushvector(L, ceilf(v[0]), ceilf(v[1]), ceilf(v[2]));
+#endif
+
+    return 1;
+}
+
+static int vector_abs(lua_State* L)
+{
+    const float* v = luaL_checkvector(L, 1);
+
+#if LUA_VECTOR_SIZE == 4
+    lua_pushvector(L, fabsf(v[0]), fabsf(v[1]), fabsf(v[2]), fabsf(v[3]));
+#else
+    lua_pushvector(L, fabsf(v[0]), fabsf(v[1]), fabsf(v[2]));
+#endif
+
+    return 1;
+}
+
+static int vector_sign(lua_State* L)
+{
+    const float* v = luaL_checkvector(L, 1);
+
+#if LUA_VECTOR_SIZE == 4
+    lua_pushvector(L, luaui_signf(v[0]), luaui_signf(v[1]), luaui_signf(v[2]), luaui_signf(v[3]));
+#else
+    lua_pushvector(L, luaui_signf(v[0]), luaui_signf(v[1]), luaui_signf(v[2]));
+#endif
+
+    return 1;
+}
+
+static int vector_clamp(lua_State* L)
+{
+    const float* v = luaL_checkvector(L, 1);
+    const float* min = luaL_checkvector(L, 2);
+    const float* max = luaL_checkvector(L, 3);
+
+    luaL_argcheck(L, min[0] <= max[0], 3, "max.x must be greater than or equal to min.x");
+    luaL_argcheck(L, min[1] <= max[1], 3, "max.y must be greater than or equal to min.y");
+    luaL_argcheck(L, min[2] <= max[2], 3, "max.z must be greater than or equal to min.z");
+
+#if LUA_VECTOR_SIZE == 4
+    lua_pushvector(
+        L,
+        luaui_clampf(v[0], min[0], max[0]),
+        luaui_clampf(v[1], min[1], max[1]),
+        luaui_clampf(v[2], min[2], max[2]),
+        luaui_clampf(v[3], min[3], max[3])
+    );
+#else
+    lua_pushvector(L, luaui_clampf(v[0], min[0], max[0]), luaui_clampf(v[1], min[1], max[1]), luaui_clampf(v[2], min[2], max[2]));
+#endif
+
+    return 1;
+}
+
+static int vector_min(lua_State* L)
+{
+    int n = lua_gettop(L);
+    const float* v = luaL_checkvector(L, 1);
+
+#if LUA_VECTOR_SIZE == 4
+    float result[] = {v[0], v[1], v[2], v[3]};
+#else
+    float result[] = {v[0], v[1], v[2]};
+#endif
+
+    for (int i = 2; i <= n; i++)
+    {
+        const float* b = luaL_checkvector(L, i);
+
+        if (b[0] < result[0])
+            result[0] = b[0];
+        if (b[1] < result[1])
+            result[1] = b[1];
+        if (b[2] < result[2])
+            result[2] = b[2];
+#if LUA_VECTOR_SIZE == 4
+        if (b[3] < result[3])
+            result[3] = b[3];
+#endif
+    }
+
+#if LUA_VECTOR_SIZE == 4
+    lua_pushvector(L, result[0], result[1], result[2], result[3]);
+#else
+    lua_pushvector(L, result[0], result[1], result[2]);
+#endif
+
+    return 1;
+}
+
+static int vector_max(lua_State* L)
+{
+    int n = lua_gettop(L);
+    const float* v = luaL_checkvector(L, 1);
+
+#if LUA_VECTOR_SIZE == 4
+    float result[] = {v[0], v[1], v[2], v[3]};
+#else
+    float result[] = {v[0], v[1], v[2]};
+#endif
+
+    for (int i = 2; i <= n; i++)
+    {
+        const float* b = luaL_checkvector(L, i);
+
+        if (b[0] > result[0])
+            result[0] = b[0];
+        if (b[1] > result[1])
+            result[1] = b[1];
+        if (b[2] > result[2])
+            result[2] = b[2];
+#if LUA_VECTOR_SIZE == 4
+        if (b[3] > result[3])
+            result[3] = b[3];
+#endif
+    }
+
+#if LUA_VECTOR_SIZE == 4
+    lua_pushvector(L, result[0], result[1], result[2], result[3]);
+#else
+    lua_pushvector(L, result[0], result[1], result[2]);
+#endif
+
+    return 1;
+}
+
+static const luaL_Reg vectorlib[] = {
+    {"create", vector_create},
+    {"magnitude", vector_magnitude},
+    {"normalize", vector_normalize},
+    {"cross", vector_cross},
+    {"dot", vector_dot},
+    {"angle", vector_angle},
+    {"floor", vector_floor},
+    {"ceil", vector_ceil},
+    {"abs", vector_abs},
+    {"sign", vector_sign},
+    {"clamp", vector_clamp},
+    {"max", vector_max},
+    {"min", vector_min},
+    {NULL, NULL},
+};
+
+int luaopen_vector(lua_State* L)
+{
+    luaL_register(L, LUA_VECLIBNAME, vectorlib);
+
+#if LUA_VECTOR_SIZE == 4
+    lua_pushvector(L, 0.0f, 0.0f, 0.0f, 0.0f);
+    lua_setfield(L, -2, "zero");
+    lua_pushvector(L, 1.0f, 1.0f, 1.0f, 1.0f);
+    lua_setfield(L, -2, "one");
+#else
+    lua_pushvector(L, 0.0f, 0.0f, 0.0f);
+    lua_setfield(L, -2, "zero");
+    lua_pushvector(L, 1.0f, 1.0f, 1.0f);
+    lua_setfield(L, -2, "one");
+#endif
+
+    return 1;
+}

bench/tests/mesh-normal-vector.lua

@@ -0,0 +1,165 @@
+--!strict
+local function prequire(name) local success, result = pcall(require, name); return if success then result else nil end
+local bench = script and require(script.Parent.bench_support) or prequire("bench_support") or require("../bench_support")
+
+function test()
+
+    type Vertex = { p: vector, uv: vector, n: vector, t: vector, b: vector, h: number }
+
+    local grid_size = 100
+
+    local mesh: {
+        vertices: {Vertex},
+        indices: {number},
+        triangle_cone_p: {vector},
+        triangle_cone_n: {vector}
+    } = {
+        vertices = table.create(grid_size * grid_size),
+        indices = table.create((grid_size - 1) * (grid_size - 1) * 6),
+        triangle_cone_p = table.create((grid_size - 1) * (grid_size - 1) * 2),
+        triangle_cone_n = table.create((grid_size - 1) * (grid_size - 1) * 2)
+    }
+    
+    function init_vertices()
+        local i = 1
+        for y = 1,grid_size do
+            for x = 1,grid_size do
+                local v: Vertex = {}
+                
+                v.p = vector.create(x, y, math.cos(x) + math.sin(y))
+                v.uv = vector.create((x-1)/(grid_size-1), (y-1)/(grid_size-1), 0)
+                v.n = vector.create(0, 0, 0)
+                v.b = vector.create(0, 0, 0)
+                v.t = vector.create(0, 0, 0)
+                v.h = 0
+                
+                mesh.vertices[i] = v
+                i += 1
+            end
+        end
+    end
+    
+    function init_indices()
+        local i = 1
+        for y = 1,grid_size-1 do
+            for x = 1,grid_size-1 do
+                mesh.indices[i] = x + (y-1)*grid_size
+                i += 1
+                mesh.indices[i] = x + y*grid_size
+                i += 1
+                mesh.indices[i] = (x+1) + (y-1)*grid_size
+                i += 1
+                mesh.indices[i] = (x+1) + (y-1)*grid_size
+                i += 1
+                mesh.indices[i] = x + y*grid_size
+                i += 1
+                mesh.indices[i] = (x+1) + y*grid_size
+                i += 1
+            end
+        end
+    end
+    
+    function calculate_normals()
+        local norm_sum = 0
+        
+        for i = 1,#mesh.indices,3 do
+            local a = mesh.vertices[mesh.indices[i]]
+            local b = mesh.vertices[mesh.indices[i + 1]]
+            local c = mesh.vertices[mesh.indices[i + 2]]
+            
+            local n = vector.cross(a.p - b.p, a.p - c.p)
+            
+            a.n += n
+            b.n += n
+            c.n += n
+        end
+        
+        for _,v in ipairs(mesh.vertices) do
+            v.n = vector.normalize(v.n)
+    
+            norm_sum += vector.dot(v.n, v.n)
+        end
+        
+        return norm_sum
+    end
+    
+    function compute_triangle_cones()
+        local mesh_area = 0
+        
+        local i = 1
+        for i = 1,#mesh.indices,3 do
+            local p0 = mesh.vertices[mesh.indices[i]]
+            local p1 = mesh.vertices[mesh.indices[i + 1]]
+            local p2 = mesh.vertices[mesh.indices[i + 2]]
+            
+            local p10 = p1.p - p0.p
+            local p20 = p2.p - p0.p
+            
+            local normal = vector.cross(p10, p20)
+    
+            local area = vector.magnitude(normal)
+            local invarea = (area == 0) and 0 or 1 / area;
+            
+            mesh.triangle_cone_p[i] = (p0.p + p1.p + p2.p) / 3
+            mesh.triangle_cone_n[i] = normal * invarea
+            i += 1
+    
+            mesh_area += area
+        end
+    
+        return mesh_area
+    end
+    
+    function compute_tangent_space()
+        local checksum = 0
+        
+        for i = 1,#mesh.indices,3 do
+            local a = mesh.vertices[mesh.indices[i]]
+            local b = mesh.vertices[mesh.indices[i + 1]]
+            local c = mesh.vertices[mesh.indices[i + 2]]
+    
+            local vba = b.p - a.p
+            local vca = c.p - a.p
+    
+            local uvba = b.uv - a.uv
+            local uvca = c.uv - a.uv
+    
+            local r = 1.0 / (uvba.X * uvca.Y - uvca.X * uvba.Y);
+    
+            local sdir = (uvca.Y * vba - uvba.Y * vca) * r
+            local tdir = (uvba.X * vca - uvca.X * vba) * r
+            
+            a.t += sdir
+            b.t += sdir
+            c.t += sdir
+            
+            a.b += tdir
+            b.b += tdir
+            c.b += tdir
+        end
+        
+        for _,v in ipairs(mesh.vertices) do
+            local t = v.t
+            
+            -- Gram-Schmidt orthogonalize
+            v.t = vector.normalize(t - v.n * vector.dot(v.n, t))
+            
+            local ht = vector.dot(vector.cross(v.n, t), v.b)
+            
+            v.h = ht < 0 and -1 or 1
+            
+            checksum += v.t.X + v.h
+        end
+        
+        return checksum
+    end
+    
+
+    init_vertices()
+    init_indices()
+    calculate_normals()
+    compute_triangle_cones()
+    compute_tangent_space()
+end
+
+bench.runCode(test, "mesh-normal-vector")

bench/tests/vector-math.lua

@@ -0,0 +1,39 @@
+local function prequire(name) local success, result = pcall(require, name); if success then return result end return nil end
+local bench = script and require(script.Parent.bench_support) or prequire("bench_support") or require("../bench_support")
+
+function fma(a: vector, b: vector, c: vector)
+    return a * b + c
+end
+
+function approx(a: vector): vector
+    local r = vector.create(1, 1, 1)
+    local aa = a
+    r += aa * 0.123
+    aa *= a
+    r += aa * 0.123
+    aa *= a
+    r += aa * 0.123
+    aa *= a
+    r += aa * 0.123
+    aa *= a
+    r += aa * 0.123
+    aa *= a
+    r += aa * 0.123
+    return r
+end
+
+function test()
+    local A = vector.create(1, 2, 3)
+    local B = vector.create(4, 5, 6)
+    local C = vector.create(7, 8, 9)
+    local fma = fma
+    local approx = approx
+
+    for i=1,100000 do
+        fma(A, B, C)
+
+        approx(A)
+    end
+end
+
+bench.runCode(test, "vector math")

tests/AstQuery.test.cpp

@@ -209,7 +209,7 @@ TEST_SUITE_BEGIN("AstQuery");
 
 TEST_CASE_FIXTURE(Fixture, "last_argument_function_call_type")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     check(R"(
 local function foo() return 2 end

tests/Compiler.test.cpp

@@ -22,6 +22,7 @@ LUAU_FASTINT(LuauCompileLoopUnrollThreshold)
 LUAU_FASTINT(LuauCompileLoopUnrollThresholdMaxBoost)
 LUAU_FASTINT(LuauRecursionLimit)
 LUAU_FASTFLAG(LuauUserDefinedTypeFunctionsSyntax2)
+LUAU_FASTFLAG(LuauCompileVectorTypeInfo)
 
 using namespace Luau;
 
@@ -94,6 +95,8 @@ TEST_CASE("BytecodeIsStable")
     // Note: these aren't strictly bound to specific bytecode versions, but must monotonically increase to keep backwards compat
     CHECK(LBF_VECTOR == 54);
     CHECK(LBF_TOSTRING == 63);
+    CHECK(LBF_BUFFER_WRITEF64 == 77);
+    CHECK(LBF_VECTOR_MAX == 88);
 
     // Bytecode capture type (serialized & in-memory)
     CHECK(LCT_UPVAL == 2); // bytecode v1
@@ -8417,6 +8420,21 @@ end
     );
 }
 
+TEST_CASE("BuiltinTypeVector")
+{
+    ScopedFastFlag luauCompileVectorTypeInfo{FFlag::LuauCompileVectorTypeInfo, true};
+
+    CHECK_EQ(
+        "\n" + compileTypeTable(R"(
+function myfunc(test: Instance, pos: vector)
+end
+)"),
+        R"(
+0: function(userdata, vector)
+)"
+    );
+}
+
 TEST_CASE("TypeAliasScoping")
 {
     CHECK_EQ(

tests/Conformance.test.cpp

@@ -36,6 +36,9 @@ LUAU_FASTFLAG(DebugLuauAbortingChecks)
 LUAU_FASTINT(CodegenHeuristicsInstructionLimit)
 LUAU_FASTFLAG(LuauNativeAttribute)
 LUAU_DYNAMIC_FASTFLAG(LuauStackLimit)
+LUAU_FASTFLAG(LuauVectorDefinitions)
+LUAU_DYNAMIC_FASTFLAG(LuauDebugInfoInvArgLeftovers)
+LUAU_FASTFLAG(LuauVectorLibNativeCodegen)
 
 static lua_CompileOptions defaultOptions()
 {
@@ -884,6 +887,30 @@ TEST_CASE("Vector")
     );
 }
 
+TEST_CASE("VectorLibrary")
+{
+    ScopedFastFlag luauVectorLibNativeCodegen{FFlag::LuauVectorLibNativeCodegen, true};
+
+    lua_CompileOptions copts = defaultOptions();
+
+    SUBCASE("O0")
+    {
+        copts.optimizationLevel = 0;
+    }
+    SUBCASE("O1")
+    {
+        copts.optimizationLevel = 1;
+    }
+    SUBCASE("O2")
+    {
+        copts.optimizationLevel = 2;
+    }
+
+    runConformance(
+        "vector_library.lua", [](lua_State* L) {}, nullptr, nullptr, &copts
+    );
+}
+
 static void populateRTTI(lua_State* L, Luau::TypeId type)
 {
     if (auto p = Luau::get<Luau::PrimitiveType>(type))
@@ -943,6 +970,10 @@ static void populateRTTI(lua_State* L, Luau::TypeId type)
 
         lua_pushstring(L, "function");
     }
+    else if (auto c = Luau::get<Luau::ClassType>(type))
+    {
+        lua_pushstring(L, c->name.c_str());
+    }
     else
     {
         LUAU_ASSERT(!"Unknown type");
@@ -951,6 +982,8 @@ static void populateRTTI(lua_State* L, Luau::TypeId type)
 
 TEST_CASE("Types")
 {
+    ScopedFastFlag luauVectorDefinitions{FFlag::LuauVectorDefinitions, true};
+
     runConformance(
         "types.lua",
         [](lua_State* L)
@@ -982,6 +1015,8 @@ TEST_CASE("DateTime")
 
 TEST_CASE("Debug")
 {
+    ScopedFastFlag luauDebugInfoInvArgLeftovers{DFFlag::LuauDebugInfoInvArgLeftovers, true};
+
     runConformance("debug.lua");
 }
 
@@ -2196,9 +2231,7 @@ TEST_CASE("UserdataApi")
     lua_getuserdatametatable(L, 50);
     lua_setmetatable(L, -2);
 
-    void* ud8 = lua_newuserdatatagged(L, 16, 51);
-    lua_getuserdatametatable(L, 51);
-    lua_setmetatable(L, -2);
+    void* ud8 = lua_newuserdatataggedwithmetatable(L, 16, 51);
 
     CHECK(luaL_checkudata(L, -2, "udata3") == ud7);
     CHECK(luaL_checkudata(L, -1, "udata4") == ud8);

tests/Differ.test.cpp

@@ -234,7 +234,7 @@ TEST_CASE_FIXTURE(DifferFixture, "right_cyclic_table_left_table_property_wrong")
 
 TEST_CASE_FIXTURE(DifferFixture, "equal_table_two_cyclic_tables_are_not_different")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
     local function id<a>(x: a): a
@@ -1473,7 +1473,7 @@ TEST_CASE_FIXTURE(DifferFixtureWithBuiltins, "equal_metatable")
 
 TEST_CASE_FIXTURE(DifferFixtureWithBuiltins, "metatable_normal")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
     local metaFoo = {

tests/Fixture.cpp

@@ -28,6 +28,8 @@ LUAU_FASTFLAG(LuauSolverV2);
 LUAU_FASTFLAG(DebugLuauLogSolverToJsonFile)
 LUAU_DYNAMIC_FASTINT(LuauTypeSolverRelease)
 
+LUAU_FASTFLAGVARIABLE(DebugLuauForceAllNewSolverTests);
+
 extern std::optional<unsigned> randomSeed; // tests/main.cpp
 
 namespace Luau

tests/Fixture.h

@@ -26,6 +26,12 @@
 #include <vector>
 
 LUAU_FASTFLAG(DebugLuauFreezeArena)
+LUAU_FASTFLAG(DebugLuauForceAllNewSolverTests)
+
+#define DOES_NOT_PASS_NEW_SOLVER_GUARD_IMPL(line) \
+    ScopedFastFlag sff_##line{FFlag::LuauSolverV2, FFlag::DebugLuauForceAllNewSolverTests};
+
+#define DOES_NOT_PASS_NEW_SOLVER_GUARD() DOES_NOT_PASS_NEW_SOLVER_GUARD_IMPL(__LINE__)
 
 namespace Luau
 {

tests/Frontend.test.cpp

@@ -12,7 +12,8 @@
 
 using namespace Luau;
 
-LUAU_FASTFLAG(LuauSolverV2)
+LUAU_FASTFLAG(LuauSolverV2);
+LUAU_FASTFLAG(LuauRequireCyclesDontAlwaysReturnAny);
 LUAU_FASTFLAG(DebugLuauFreezeArena);
 LUAU_FASTFLAG(DebugLuauMagicTypes);
 
@@ -313,6 +314,8 @@ TEST_CASE_FIXTURE(FrontendFixture, "nocheck_cycle_used_by_checked")
 
     if (FFlag::LuauSolverV2)
         CHECK_EQ("{ a: { hello: any }, b: { hello: any } }", toString(*cExports));
+    else if (FFlag::LuauRequireCyclesDontAlwaysReturnAny)
+        CHECK("{| a: any, b: any |}, {| a: {| hello: any |}, b: {| hello: any |} |}" == toString(*cExports));
     else
         CHECK_EQ("{| a: any, b: any |}", toString(*cExports));
 }
@@ -1375,7 +1378,7 @@ TEST_CASE_FIXTURE(FrontendFixture, "checked_modules_have_the_correct_mode")
 
 TEST_CASE_FIXTURE(FrontendFixture, "separate_caches_for_autocomplete")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     fileResolver.source["game/A"] = R"(
         --!nonstrict

tests/Module.test.cpp

@@ -110,9 +110,7 @@ TEST_CASE_FIXTURE(Fixture, "deepClone_cyclic_table")
     // breaks this test.  I'm not sure if that behaviour change is important or
     // not, but it's tangental to the core purpose of this test.
 
-    ScopedFastFlag sff[] = {
-        {FFlag::LuauSolverV2, false},
-    };
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local Cyclic = {}
@@ -283,7 +281,7 @@ TEST_CASE_FIXTURE(Fixture, "clone_class")
 
 TEST_CASE_FIXTURE(Fixture, "clone_free_types")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     TypeArena arena;
     TypeId freeTy = freshType(NotNull{&arena}, builtinTypes, nullptr);

tests/NonstrictMode.test.cpp

@@ -16,7 +16,7 @@ TEST_SUITE_BEGIN("NonstrictModeTests");
 
 TEST_CASE_FIXTURE(Fixture, "infer_nullary_function")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
     CheckResult result = check(R"(
         --!nonstrict
         function foo(x, y) end
@@ -39,7 +39,7 @@ TEST_CASE_FIXTURE(Fixture, "infer_nullary_function")
 
 TEST_CASE_FIXTURE(Fixture, "infer_the_maximum_number_of_values_the_function_could_return")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
     CheckResult result = check(R"(
         --!nonstrict
         function getMinCardCountForWidth(width)
@@ -103,7 +103,7 @@ TEST_CASE_FIXTURE(Fixture, "inconsistent_return_types_are_ok")
 
 TEST_CASE_FIXTURE(Fixture, "locals_are_any_by_default")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
     CheckResult result = check(R"(
         --!nonstrict
         local m = 55
@@ -130,7 +130,7 @@ TEST_CASE_FIXTURE(Fixture, "parameters_having_type_any_are_optional")
 
 TEST_CASE_FIXTURE(Fixture, "local_tables_are_not_any")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
     CheckResult result = check(R"(
         --!nonstrict
         local T = {}
@@ -148,7 +148,7 @@ TEST_CASE_FIXTURE(Fixture, "local_tables_are_not_any")
 
 TEST_CASE_FIXTURE(Fixture, "offer_a_hint_if_you_use_a_dot_instead_of_a_colon")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
     CheckResult result = check(R"(
         --!nonstrict
         local T = {}
@@ -163,7 +163,7 @@ TEST_CASE_FIXTURE(Fixture, "offer_a_hint_if_you_use_a_dot_instead_of_a_colon")
 
 TEST_CASE_FIXTURE(Fixture, "table_props_are_any")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
     CheckResult result = check(R"(
         --!nonstrict
         local T = {}
@@ -185,7 +185,7 @@ TEST_CASE_FIXTURE(Fixture, "table_props_are_any")
 
 TEST_CASE_FIXTURE(Fixture, "inline_table_props_are_also_any")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
     CheckResult result = check(R"(
         --!nonstrict
         local T = {
@@ -261,7 +261,7 @@ TEST_CASE_FIXTURE(Fixture, "delay_function_does_not_require_its_argument_to_retu
 
 TEST_CASE_FIXTURE(Fixture, "inconsistent_module_return_types_are_ok")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
     CheckResult result = check(R"(
         --!nonstrict
 

tests/Parser.test.cpp

@@ -1191,9 +1191,7 @@ until false
 
 TEST_CASE_FIXTURE(Fixture, "parse_nesting_based_end_detection_local_function")
 {
-    ScopedFastFlag sff[] = {
-        {FFlag::LuauSolverV2, false},
-    };
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     try
     {
@@ -1228,9 +1226,7 @@ end
 
 TEST_CASE_FIXTURE(Fixture, "parse_nesting_based_end_detection_failsafe_earlier")
 {
-    ScopedFastFlag sff[] = {
-        {FFlag::LuauSolverV2, false},
-    };
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     try
     {
@@ -2628,9 +2624,7 @@ TEST_CASE_FIXTURE(Fixture, "recovery_of_parenthesized_expressions")
         }
     };
 
-    ScopedFastFlag sff[] = {
-        {FFlag::LuauSolverV2, false},
-    };
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     checkRecovery("function foo(a, b. c) return a + b end", "function foo(a, b) return a + b end", 1);
     checkRecovery(
@@ -2872,9 +2866,7 @@ TEST_CASE_FIXTURE(Fixture, "AstName_comparison")
 
 TEST_CASE_FIXTURE(Fixture, "generic_type_list_recovery")
 {
-    ScopedFastFlag sff[] = {
-        {FFlag::LuauSolverV2, false},
-    };
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     try
     {

tests/RuntimeLimits.test.cpp

@@ -45,9 +45,7 @@ TEST_SUITE_BEGIN("RuntimeLimits");
 
 TEST_CASE_FIXTURE(LimitFixture, "typescript_port_of_Result_type")
 {
-    ScopedFastFlag sff[] = {
-        {FFlag::LuauSolverV2, false},
-    };
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     constexpr const char* src = R"LUA(
         --!strict

tests/ToDot.test.cpp

@@ -322,9 +322,7 @@ n3 [label="TableType 3"];
 
 TEST_CASE_FIXTURE(Fixture, "free")
 {
-    ScopedFastFlag sff[] = {
-        {FFlag::LuauSolverV2, false},
-    };
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     Type type{TypeVariant{FreeType{TypeLevel{0, 0}}}};
 

tests/ToString.test.cpp

@@ -45,7 +45,7 @@ TEST_CASE_FIXTURE(Fixture, "bound_types")
 
 TEST_CASE_FIXTURE(Fixture, "free_types")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check("local a");
     LUAU_REQUIRE_NO_ERRORS(result);
@@ -166,7 +166,7 @@ TEST_CASE_FIXTURE(Fixture, "named_metatable")
 
 TEST_CASE_FIXTURE(BuiltinsFixture, "named_metatable_toStringNamedFunction")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local function createTbl(): NamedMetatable
@@ -594,7 +594,7 @@ TEST_CASE_FIXTURE(Fixture, "toStringDetailed")
 
 TEST_CASE_FIXTURE(Fixture, "toStringErrorPack")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 local function target(callback: nil) return callback(4, "hello") end

tests/TypeFunction.user.test.cpp

@@ -13,6 +13,9 @@ LUAU_FASTFLAG(LuauUserDefinedTypeFunctions2)
 LUAU_FASTFLAG(LuauUserDefinedTypeFunctionNoEvaluation)
 LUAU_FASTFLAG(LuauUserTypeFunFixRegister)
 LUAU_FASTFLAG(LuauUserTypeFunFixNoReadWrite)
+LUAU_FASTFLAG(LuauUserTypeFunFixMetatable)
+LUAU_FASTFLAG(LuauUserDefinedTypeFunctionResetState)
+LUAU_FASTFLAG(LuauUserTypeFunNonstrict)
 
 TEST_SUITE_BEGIN("UserDefinedTypeFunctionTests");
 
@@ -987,6 +990,23 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "udtf_no_shared_state")
     CHECK(toString(result.errors[1]) == R"(Type function instance bar<"x"> is uninhabited)");
 }
 
+TEST_CASE_FIXTURE(BuiltinsFixture, "udtf_math_reset")
+{
+    ScopedFastFlag newSolver{FFlag::LuauSolverV2, true};
+    ScopedFastFlag udtfSyntax{FFlag::LuauUserDefinedTypeFunctionsSyntax2, true};
+    ScopedFastFlag udtf{FFlag::LuauUserDefinedTypeFunctions2, true};
+    ScopedFastFlag luauUserDefinedTypeFunctionResetState{FFlag::LuauUserDefinedTypeFunctionResetState, true};
+
+    CheckResult result = check(R"(
+        type function foo(x)
+            return types.singleton(tostring(math.random(1, 100)))
+        end
+        local x: foo<'a'> = ('' :: any) :: foo<'b'>
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+}
+
 TEST_CASE_FIXTURE(BuiltinsFixture, "udtf_optionify")
 {
     ScopedFastFlag newSolver{FFlag::LuauSolverV2, true};
@@ -1230,4 +1250,52 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "tag_field")
     CHECK(toString(result.errors[2]) == R"(Type pack '"table"' could not be converted into 'never'; at [0], "table" is not a subtype of never)");
 }
 
+TEST_CASE_FIXTURE(BuiltinsFixture, "metatable_serialization")
+{
+    ScopedFastFlag newSolver{FFlag::LuauSolverV2, true};
+    ScopedFastFlag udtfSyntax{FFlag::LuauUserDefinedTypeFunctionsSyntax2, true};
+    ScopedFastFlag udtf{FFlag::LuauUserDefinedTypeFunctions2, true};
+    ScopedFastFlag luauUserTypeFunFixRegister{FFlag::LuauUserTypeFunFixRegister, true};
+    ScopedFastFlag luauUserTypeFunFixMetatable{FFlag::LuauUserTypeFunFixMetatable, true};
+
+    CheckResult result = check(R"(
+        type function makemttbl()
+            local metaprops = {
+                [types.singleton("ma")] = types.boolean
+            }
+            local mt = types.newtable(metaprops)
+
+            local props = {
+                [types.singleton("a")] = types.number
+            }
+            return types.newtable(props, nil, mt)
+        end
+
+        type function id(x)
+            return x
+        end
+
+        local a: number = {} :: id<makemttbl<>>
+    )");
+
+    LUAU_REQUIRE_ERROR_COUNT(1, result);
+    CHECK(toString(result.errors[0]) == R"(Type '{ @metatable { ma: boolean }, { a: number } }' could not be converted into 'number')");
+}
+
+TEST_CASE_FIXTURE(BuiltinsFixture, "nonstrict_mode")
+{
+    ScopedFastFlag newSolver{FFlag::LuauSolverV2, true};
+    ScopedFastFlag udtfSyntax{FFlag::LuauUserDefinedTypeFunctionsSyntax2, true};
+    ScopedFastFlag udtf{FFlag::LuauUserDefinedTypeFunctions2, true};
+    ScopedFastFlag luauUserTypeFunFixRegister{FFlag::LuauUserTypeFunFixRegister, true};
+    ScopedFastFlag luauUserTypeFunNonstrict{FFlag::LuauUserTypeFunNonstrict, true};
+
+    CheckResult result = check(R"(
+--!nonstrict
+type function foo() return types.string end
+local a: foo<> = "a"
+    )");
+    LUAU_REQUIRE_NO_ERRORS(result);
+}
+
 TEST_SUITE_END();

tests/TypeInfer.aliases.test.cpp

@@ -106,7 +106,7 @@ TEST_CASE_FIXTURE(Fixture, "cannot_steal_hoisted_type_alias")
 TEST_CASE_FIXTURE(Fixture, "mismatched_generic_type_param")
 {
     // We erroneously report an extra error in this case when the new solver is enabled.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         type T<A> = (A...) -> ()
@@ -245,7 +245,7 @@ TEST_CASE_FIXTURE(Fixture, "dependent_generic_aliases")
 TEST_CASE_FIXTURE(Fixture, "mutually_recursive_generic_aliases")
 {
     // CLI-116108
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         --!strict
@@ -355,9 +355,7 @@ TEST_CASE_FIXTURE(Fixture, "stringify_type_alias_of_recursive_template_table_typ
 // Check that recursive intersection type doesn't generate an OOM
 TEST_CASE_FIXTURE(Fixture, "cli_38393_recursive_intersection_oom")
 {
-    ScopedFastFlag sff[] = {
-        {FFlag::LuauSolverV2, false},
-    }; // FIXME
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function _(l0:(t0)&((t0)&(((t0)&((t0)->()))->(typeof(_),typeof(# _)))),l39,...):any
@@ -418,7 +416,7 @@ TEST_CASE_FIXTURE(Fixture, "corecursive_function_types")
 
 TEST_CASE_FIXTURE(Fixture, "generic_param_remap")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     const std::string code = R"(
         -- An example of a forwarded use of a type that has different type arguments than parameters
@@ -544,7 +542,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "type_alias_import_mutation")
 
 TEST_CASE_FIXTURE(Fixture, "type_alias_local_mutation")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         type Cool = { a: number, b: string }
@@ -565,7 +563,7 @@ TEST_CASE_FIXTURE(Fixture, "type_alias_local_mutation")
 
 TEST_CASE_FIXTURE(Fixture, "type_alias_local_rename")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 type Cool = { a: number, b: string }
@@ -713,7 +711,7 @@ TEST_CASE_FIXTURE(Fixture, "mutually_recursive_types_restriction_ok")
 TEST_CASE_FIXTURE(Fixture, "mutually_recursive_types_restriction_not_ok_1")
 {
     // CLI-116108
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         -- OK because forwarded types are used with their parameters.
@@ -727,7 +725,7 @@ TEST_CASE_FIXTURE(Fixture, "mutually_recursive_types_restriction_not_ok_1")
 TEST_CASE_FIXTURE(Fixture, "mutually_recursive_types_restriction_not_ok_2")
 {
     // CLI-116108
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         -- Not OK because forwarded types are used with different types than their parameters.
@@ -751,7 +749,7 @@ TEST_CASE_FIXTURE(Fixture, "mutually_recursive_types_swapsies_ok")
 TEST_CASE_FIXTURE(Fixture, "mutually_recursive_types_swapsies_not_ok")
 {
     // CLI-116108
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         type Tree1<T,U> = { data: T, children: {Tree2<U,T>} }
@@ -876,7 +874,7 @@ TEST_CASE_FIXTURE(Fixture, "recursive_types_restriction_ok")
 TEST_CASE_FIXTURE(Fixture, "recursive_types_restriction_not_ok")
 {
     // CLI-116108
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         -- this would be an infinite type if we allowed it
@@ -889,7 +887,7 @@ TEST_CASE_FIXTURE(Fixture, "recursive_types_restriction_not_ok")
 TEST_CASE_FIXTURE(Fixture, "report_shadowed_aliases")
 {
     // CLI-116110
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     // We allow a previous type alias to depend on a future type alias. That exact feature enables a confusing example, like the following snippet,
     // which has the type alias FakeString point to the type alias `string` that which points to `number`.
@@ -973,7 +971,7 @@ TEST_CASE_FIXTURE(Fixture, "type_alias_locations")
 TEST_CASE_FIXTURE(BuiltinsFixture, "dont_lose_track_of_PendingExpansionTypes_after_substitution")
 {
     // CLI-114134 - We need egraphs to properly simplify these types.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     fileResolver.source["game/ReactCurrentDispatcher"] = R"(
         export type BasicStateAction<S> = ((S) -> S) | S

tests/TypeInfer.builtins.test.cpp

@@ -11,7 +11,7 @@ using namespace Luau;
 
 LUAU_FASTFLAG(LuauSolverV2)
 LUAU_DYNAMIC_FASTINT(LuauTypeSolverRelease)
-LUAU_FASTFLAG(LuauTypestateBuiltins)
+LUAU_FASTFLAG(LuauTypestateBuiltins2)
 LUAU_FASTFLAG(LuauStringFormatArityFix)
 
 TEST_SUITE_BEGIN("BuiltinTests");
@@ -136,7 +136,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "sort_with_predicate")
 
 TEST_CASE_FIXTURE(BuiltinsFixture, "sort_with_bad_predicate")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         --!strict
@@ -516,7 +516,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "buffer_is_a_type")
 
 TEST_CASE_FIXTURE(BuiltinsFixture, "coroutine_resume_anything_goes")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local function nifty(x, y)
@@ -1133,7 +1133,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "table_freeze_is_generic")
     )");
 
     LUAU_REQUIRE_ERROR_COUNT(1, result);
-    if (FFlag::LuauSolverV2 && FFlag::LuauTypestateBuiltins)
+    if (FFlag::LuauSolverV2 && FFlag::LuauTypestateBuiltins2)
         CHECK("Key 'b' not found in table '{ read a: number }'" == toString(result.errors[0]));
     else if (FFlag::LuauSolverV2)
         CHECK("Key 'b' not found in table '{ a: number }'" == toString(result.errors[0]));
@@ -1141,7 +1141,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "table_freeze_is_generic")
         CHECK_EQ("Key 'b' not found in table '{| a: number |}'", toString(result.errors[0]));
     CHECK(Location({13, 18}, {13, 23}) == result.errors[0].location);
 
-    if (FFlag::LuauSolverV2 && FFlag::LuauTypestateBuiltins)
+    if (FFlag::LuauSolverV2 && FFlag::LuauTypestateBuiltins2)
     {
         CHECK_EQ("{ read a: number }", toString(requireTypeAtPosition({15, 19})));
         CHECK_EQ("{ read b: string }", toString(requireTypeAtPosition({16, 19})));
@@ -1178,13 +1178,13 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "table_freeze_does_not_retroactively_block_mu
     LUAU_REQUIRE_NO_ERRORS(result);
 
 
-    if (FFlag::LuauTypestateBuiltins)
+    if (FFlag::LuauTypestateBuiltins2)
     {
-        CHECK_EQ("t1 | { read a: number, read q: string }", toString(requireType("t1")));
+        CHECK_EQ("{ a: number, q: string } | { read a: number, read q: string }", toString(requireType("t1"), {/*exhaustive */ true}));
         // before the assignment, it's `t1`
-        CHECK_EQ("t1", toString(requireTypeAtPosition({3, 8})));
+        CHECK_EQ("{ a: number, q: string }", toString(requireTypeAtPosition({3, 8}), {/*exhaustive */ true}));
         // after the assignment, it's read-only.
-        CHECK_EQ("{ read a: number, read q: string }", toString(requireTypeAtPosition({8, 18})));
+        CHECK_EQ("{ read a: number, read q: string }", toString(requireTypeAtPosition({8, 18}), {/*exhaustive */ true}));
     }
 
     CHECK_EQ("number", toString(requireType("a")));
@@ -1208,10 +1208,46 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "table_freeze_no_generic_table")
         end
     )");
 
-    if (FFlag::LuauTypestateBuiltins)
+    if (FFlag::LuauTypestateBuiltins2)
         LUAU_REQUIRE_NO_ERRORS(result);
 }
 
+TEST_CASE_FIXTURE(BuiltinsFixture, "table_freeze_on_metatable")
+{
+    CheckResult result = check(R"(
+        --!strict
+        local meta = {
+            __index = function()
+                return "foo"
+            end
+        }
+
+        local myTable = setmetatable({}, meta)
+        table.freeze(myTable)
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+}
+
+TEST_CASE_FIXTURE(BuiltinsFixture, "table_freeze_errors_on_no_args")
+{
+    CheckResult result = check(R"(
+        --!strict
+        table.freeze()
+    )");
+
+    // this does not error in the new solver without the typestate builtins functionality.
+    if (FFlag::LuauSolverV2 && !FFlag::LuauTypestateBuiltins2)
+    {
+        LUAU_REQUIRE_NO_ERRORS(result);
+        return;
+    }
+
+    LUAU_REQUIRE_ERROR_COUNT(1, result);
+
+    CHECK(get<CountMismatch>(result.errors[0]));
+}
+
 TEST_CASE_FIXTURE(BuiltinsFixture, "table_freeze_errors_on_non_tables")
 {
     CheckResult result = check(R"(
@@ -1220,7 +1256,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "table_freeze_errors_on_non_tables")
     )");
 
     // this does not error in the new solver without the typestate builtins functionality.
-    if (FFlag::LuauSolverV2 && !FFlag::LuauTypestateBuiltins)
+    if (FFlag::LuauSolverV2 && !FFlag::LuauTypestateBuiltins2)
     {
         LUAU_REQUIRE_NO_ERRORS(result);
         return;
@@ -1231,7 +1267,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "table_freeze_errors_on_non_tables")
     TypeMismatch* tm = get<TypeMismatch>(result.errors[0]);
     REQUIRE(tm);
 
-    if (FFlag::LuauSolverV2 && FFlag::LuauTypestateBuiltins)
+    if (FFlag::LuauSolverV2 && FFlag::LuauTypestateBuiltins2)
         CHECK_EQ(toString(tm->wantedType), "table");
     else
         CHECK_EQ(toString(tm->wantedType), "{-  -}");
@@ -1241,7 +1277,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "table_freeze_errors_on_non_tables")
 TEST_CASE_FIXTURE(BuiltinsFixture, "set_metatable_needs_arguments")
 {
     // In the new solver, nil can certainly be used where a generic is required, so all generic parameters are optional.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local a = {b=setmetatable}

tests/TypeInfer.classes.test.cpp

@@ -128,7 +128,7 @@ TEST_CASE_FIXTURE(ClassFixture, "we_can_infer_that_a_parameter_must_be_a_particu
 
 TEST_CASE_FIXTURE(ClassFixture, "we_can_report_when_someone_is_trying_to_use_a_table_rather_than_a_class")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function makeClone(o)
@@ -235,7 +235,7 @@ TEST_CASE_FIXTURE(ClassFixture, "can_assign_to_prop_of_base_class_using_string")
 TEST_CASE_FIXTURE(ClassFixture, "cannot_unify_class_instance_with_primitive")
 {
     // This is allowed in the new solver
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local v = Vector2.New(0, 5)
@@ -472,7 +472,7 @@ Type 'number' could not be converted into 'string')";
 TEST_CASE_FIXTURE(ClassFixture, "class_type_mismatch_with_name_conflict")
 {
     // CLI-116433
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 local i = ChildClass.New()

tests/TypeInfer.definitions.test.cpp

@@ -443,6 +443,26 @@ TEST_CASE_FIXTURE(Fixture, "class_definition_string_props")
     CHECK_EQ(toString(requireType("y")), "string");
 }
 
+TEST_CASE_FIXTURE(Fixture, "class_definition_malformed_string")
+{
+    unfreeze(frontend.globals.globalTypes);
+    LoadDefinitionFileResult result = frontend.loadDefinitionFile(
+        frontend.globals,
+        frontend.globals.globalScope,
+        R"(
+        declare class Foo
+            ["a\0property"]: string
+        end
+    )",
+        "@test",
+        /* captureComments */ false
+    );
+    freeze(frontend.globals.globalTypes);
+
+    REQUIRE(!result.success);
+    REQUIRE_EQ(result.parseResult.errors.size(), 1);
+    CHECK_EQ(result.parseResult.errors[0].getMessage(), "String literal contains malformed escape sequence or \\0");
+}
 
 TEST_CASE_FIXTURE(Fixture, "class_definition_indexer")
 {

tests/TypeInfer.functions.test.cpp

@@ -16,9 +16,10 @@
 
 using namespace Luau;
 
-LUAU_FASTFLAG(LuauInstantiateInSubtyping);
-LUAU_FASTFLAG(LuauSolverV2);
-LUAU_FASTINT(LuauTarjanChildLimit);
+LUAU_FASTFLAG(LuauInstantiateInSubtyping)
+LUAU_FASTFLAG(LuauSolverV2)
+LUAU_FASTINT(LuauTarjanChildLimit)
+LUAU_FASTFLAG(LuauRetrySubtypingWithoutHiddenPack)
 
 TEST_SUITE_BEGIN("TypeInferFunctions");
 
@@ -310,7 +311,7 @@ TEST_CASE_FIXTURE(Fixture, "infer_return_type_from_selected_overload")
 TEST_CASE_FIXTURE(Fixture, "too_many_arguments")
 {
     // This is not part of the new non-strict specification currently.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         --!nonstrict
@@ -602,7 +603,7 @@ TEST_CASE_FIXTURE(Fixture, "duplicate_functions_allowed_in_nonstrict")
 TEST_CASE_FIXTURE(Fixture, "duplicate_functions_with_different_signatures_not_allowed_in_nonstrict")
 {
     // This is not part of the spec for the new non-strict mode currently.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         --!nonstrict
@@ -881,7 +882,7 @@ TEST_CASE_FIXTURE(Fixture, "another_indirect_function_case_where_it_is_ok_to_pro
 TEST_CASE_FIXTURE(Fixture, "report_exiting_without_return_nonstrict")
 {
     // new non-strict mode spec does not include this error yet.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         --!nonstrict
@@ -1016,7 +1017,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "calling_function_with_anytypepack_doesnt_lea
 TEST_CASE_FIXTURE(Fixture, "too_many_return_values")
 {
     // FIXME: CLI-116157 variadic and generic type packs seem to be interacting incorrectly.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         --!strict
@@ -1040,7 +1041,7 @@ TEST_CASE_FIXTURE(Fixture, "too_many_return_values")
 TEST_CASE_FIXTURE(Fixture, "too_many_return_values_in_parentheses")
 {
     // FIXME: CLI-116157 variadic and generic type packs seem to be interacting incorrectly.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         --!strict
@@ -1064,7 +1065,7 @@ TEST_CASE_FIXTURE(Fixture, "too_many_return_values_in_parentheses")
 TEST_CASE_FIXTURE(Fixture, "too_many_return_values_no_function")
 {
     // FIXME: CLI-116157 variadic and generic type packs seem to be interacting incorrectly.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         --!strict
@@ -1233,7 +1234,7 @@ TEST_CASE_FIXTURE(Fixture, "return_type_by_overload")
 TEST_CASE_FIXTURE(BuiltinsFixture, "infer_anonymous_function_arguments")
 {
     // FIXME: CLI-116133 bidirectional type inference needs to push expected types in for higher-order function calls
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     // Simple direct arg to arg propagation
     CheckResult result = check(R"(
@@ -1352,7 +1353,7 @@ f(function(x) return x * 2 end)
 TEST_CASE_FIXTURE(BuiltinsFixture, "infer_generic_function_function_argument")
 {
     // FIXME: CLI-116133 bidirectional type inference needs to push expected types in for higher-order function calls
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 local function sum<a>(x: a, y: a, f: (a, a) -> a) return f(x, y) end
@@ -1383,7 +1384,7 @@ local r = foldl(a, {s=0,c=0}, function(a, b) return {s = a.s + b, c = a.c + 1} e
 TEST_CASE_FIXTURE(Fixture, "infer_generic_function_function_argument_overloaded")
 {
     // FIXME: CLI-116133 bidirectional type inference needs to push expected types in for higher-order function calls
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 local function g1<T>(a: T, f: (T) -> T) return f(a) end
@@ -1450,7 +1451,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "variadic_any_is_compatible_with_a_generic_Ty
 TEST_CASE_FIXTURE(Fixture, "infer_anonymous_function_arguments_outside_call")
 {
     // FIXME: CLI-116133 bidirectional type inference needs to push expected types in for higher-order function calls
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 type Table = { x: number, y: number }
@@ -1493,7 +1494,7 @@ end
 TEST_CASE_FIXTURE(Fixture, "error_detailed_function_mismatch_arg_count")
 {
     // FIXME: CLI-116111 test disabled until type path stringification is improved
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 type A = (number, number) -> string
@@ -1516,7 +1517,7 @@ caused by:
 TEST_CASE_FIXTURE(Fixture, "error_detailed_function_mismatch_arg")
 {
     // FIXME: CLI-116111 test disabled until type path stringification is improved
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 type A = (number, number) -> string
@@ -1540,7 +1541,7 @@ Type 'string' could not be converted into 'number')";
 TEST_CASE_FIXTURE(Fixture, "error_detailed_function_mismatch_ret_count")
 {
     // FIXME: CLI-116111 test disabled until type path stringification is improved
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 type A = (number, number) -> (number)
@@ -1563,7 +1564,7 @@ caused by:
 TEST_CASE_FIXTURE(Fixture, "error_detailed_function_mismatch_ret")
 {
     // FIXME: CLI-116111 test disabled until type path stringification is improved
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 type A = (number, number) -> string
@@ -1587,7 +1588,7 @@ Type 'string' could not be converted into 'number')";
 TEST_CASE_FIXTURE(Fixture, "error_detailed_function_mismatch_ret_mult")
 {
     // FIXME: CLI-116111 test disabled until type path stringification is improved
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 type A = (number, number) -> (number, string)
@@ -1718,7 +1719,7 @@ TEST_CASE_FIXTURE(Fixture, "inferred_higher_order_functions_are_quantified_at_th
 {
     // This test regresses in the new solver, but is sort of nonsensical insofar as `foo` is known to be `nil`, so it's "right" to not be able to call
     // it.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local foo
@@ -1787,7 +1788,7 @@ TEST_CASE_FIXTURE(Fixture, "strict_mode_ok_with_missing_arguments")
 TEST_CASE_FIXTURE(Fixture, "function_statement_sealed_table_assignment_through_indexer")
 {
     // FIXME: CLI-116122 bug where `t:b` does not check against the type from the indexer annotation on `t`.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 local t: {[string]: () -> number} = {}
@@ -1832,7 +1833,7 @@ TEST_CASE_FIXTURE(Fixture, "too_few_arguments_variadic")
 TEST_CASE_FIXTURE(Fixture, "too_few_arguments_variadic_generic")
 {
     // FIXME: CLI-116157 variadic and generic type packs seem to be interacting incorrectly.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 function test(a: number, b: string, ...)
@@ -1860,7 +1861,7 @@ wrapper(test)
 TEST_CASE_FIXTURE(BuiltinsFixture, "too_few_arguments_variadic_generic2")
 {
     // FIXME: CLI-116157 variadic and generic type packs seem to be interacting incorrectly.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 function test(a: number, b: string, ...)
@@ -2014,7 +2015,7 @@ u.b().foo()
 TEST_CASE_FIXTURE(BuiltinsFixture, "improved_function_arg_mismatch_error_nonstrict")
 {
     // This behavior is not part of the current specification of the new type solver.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         --!nonstrict
@@ -2029,7 +2030,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "improved_function_arg_mismatch_error_nonstri
 TEST_CASE_FIXTURE(Fixture, "luau_subtyping_is_np_hard")
 {
     // The case that _should_ succeed here (`z = x`) does not currently in the new solver.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 --!strict
@@ -2994,4 +2995,25 @@ local u,v = id(3), id(id(44))
     LUAU_REQUIRE_NO_ERRORS(result);
 }
 
+TEST_CASE_FIXTURE(Fixture, "hidden_variadics_should_not_break_subtyping")
+{
+    // Only applies to new solver.
+    ScopedFastFlag sff{FFlag::LuauRetrySubtypingWithoutHiddenPack, true};
+
+    CheckResult result = check(R"(
+        --!strict
+        type FooType = {
+            SetValue: (Value: number) -> ()
+        }
+
+        local Foo: FooType = {
+            SetValue = function(Value: number)
+
+            end
+        }
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+}
+
 TEST_SUITE_END();

tests/TypeInfer.generics.test.cpp

@@ -143,7 +143,7 @@ TEST_CASE_FIXTURE(Fixture, "properties_can_be_polytypes")
 
 TEST_CASE_FIXTURE(Fixture, "properties_can_be_instantiated_polytypes")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local t: { m: (number)->number } = { m = function(x:number) return x+1 end }
@@ -261,7 +261,7 @@ TEST_CASE_FIXTURE(Fixture, "check_mutual_generic_functions_errors")
 
 TEST_CASE_FIXTURE(Fixture, "generic_functions_in_types_old_solver")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         type T = { id: <a>(a) -> a }
@@ -287,7 +287,7 @@ TEST_CASE_FIXTURE(Fixture, "generic_functions_in_types_new_solver")
 
 TEST_CASE_FIXTURE(Fixture, "generic_factories")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         type T<a> = { id: (a) -> a }
@@ -310,7 +310,7 @@ TEST_CASE_FIXTURE(Fixture, "generic_factories")
 
 TEST_CASE_FIXTURE(Fixture, "factories_of_generics")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         type T = { id: <a>(a) -> a }
@@ -775,7 +775,7 @@ return exports
 
 TEST_CASE_FIXTURE(Fixture, "instantiated_function_argument_names_old_solver")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local function f<T, U...>(a: T, ...: U...) end
@@ -794,7 +794,7 @@ TEST_CASE_FIXTURE(Fixture, "instantiated_function_argument_names_old_solver")
 
 TEST_CASE_FIXTURE(Fixture, "error_detailed_function_mismatch_generic_types")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 type C = () -> ()
@@ -811,7 +811,7 @@ local d: D = c
 
 TEST_CASE_FIXTURE(Fixture, "error_detailed_function_mismatch_generic_pack")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 type C = () -> ()
@@ -887,7 +887,7 @@ Type 'number' could not be converted into 'string' in an invariant context)";
 
 TEST_CASE_FIXTURE(Fixture, "generic_type_pack_unification1")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 --!strict
@@ -907,7 +907,7 @@ local TheDispatcher: Dispatcher = {
 
 TEST_CASE_FIXTURE(Fixture, "generic_type_pack_unification2")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 --!strict
@@ -927,7 +927,7 @@ local TheDispatcher: Dispatcher = {
 
 TEST_CASE_FIXTURE(Fixture, "generic_type_pack_unification3")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 --!strict
@@ -947,7 +947,7 @@ local TheDispatcher: Dispatcher = {
 
 TEST_CASE_FIXTURE(Fixture, "generic_argument_count_too_few")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 function test(a: number)
@@ -966,7 +966,7 @@ wrapper(test)
 
 TEST_CASE_FIXTURE(Fixture, "generic_argument_count_too_many")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 function test2(a: number, b: string)
@@ -1463,7 +1463,7 @@ TEST_CASE_FIXTURE(Fixture, "no_extra_quantification_for_generic_functions")
 
 TEST_CASE_FIXTURE(Fixture, "do_not_always_instantiate_generic_intersection_types")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         --!strict
@@ -1498,8 +1498,9 @@ end
 
 TEST_CASE_FIXTURE(BuiltinsFixture, "higher_rank_polymorphism_should_not_accept_instantiated_arguments")
 {
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
+
     ScopedFastFlag sffs[] = {
-        {FFlag::LuauSolverV2, false},
         {FFlag::LuauInstantiateInSubtyping, true},
     };
 
@@ -1579,7 +1580,7 @@ TEST_CASE_FIXTURE(Fixture, "generic_implicit_explicit_name_clash")
 
 TEST_CASE_FIXTURE(BuiltinsFixture, "generic_type_functions_work_in_subtyping")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     if (!FFlag::LuauSolverV2)
         return;

tests/TypeInfer.intersectionTypes.test.cpp

@@ -332,9 +332,9 @@ TEST_CASE_FIXTURE(Fixture, "table_intersection_write_sealed")
 
 TEST_CASE_FIXTURE(Fixture, "table_intersection_write_sealed_indirect")
 {
-    ScopedFastFlag dcr{
-        FFlag::LuauSolverV2, false
-    }; // CLI-116476 Subtyping between type alias and an equivalent but not named type isn't working.
+    // CLI-116476 Subtyping between type alias and an equivalent but not named type isn't working.
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
+
     CheckResult result = check(R"(
         type X = { x: (number) -> number }
         type Y = { y: (string) -> string }
@@ -372,7 +372,7 @@ caused by:
 
 TEST_CASE_FIXTURE(Fixture, "table_write_sealed_indirect")
 {
-    ScopedFastFlag dcr{FFlag::LuauSolverV2, false}; // CLI-
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
     // After normalization, previous 'table_intersection_write_sealed_indirect' is identical to this one
     CheckResult result = check(R"(
     type XY = { x: (number) -> number, y: (string) -> string }
@@ -581,9 +581,9 @@ could not be converted into
 
 TEST_CASE_FIXTURE(Fixture, "union_saturate_overloaded_functions")
 {
-    ScopedFastFlag dcr{
-        FFlag::LuauSolverV2, false
-    }; // CLI-116474 Semantic subtyping of assignments needs to decide how to interpret intersections of functions
+    // CLI-116474 Semantic subtyping of assignments needs to decide how to interpret intersections of functions
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
+
     CheckResult result = check(R"(
         function f(x: ((number) -> number) & ((string) -> string))
             local y : ((number | string) -> (number | string)) = x -- OK
@@ -811,9 +811,9 @@ could not be converted into
 
 TEST_CASE_FIXTURE(Fixture, "overloadeded_functions_with_unknown_result")
 {
-    ScopedFastFlag dcr{
-        FFlag::LuauSolverV2, false
-    }; // CLI-116474 Semantic subtyping of assignments needs to decide how to interpret intersections of functions
+    // CLI-116474 Semantic subtyping of assignments needs to decide how to interpret intersections of functions
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
+
     CheckResult result = check(R"(
         function f<a...,b...>()
             function g(x : ((number) -> number) & ((nil) -> unknown))
@@ -833,9 +833,9 @@ could not be converted into
 
 TEST_CASE_FIXTURE(Fixture, "overloadeded_functions_with_unknown_arguments")
 {
-    ScopedFastFlag dcr{
-        FFlag::LuauSolverV2, false
-    }; // CLI-116474 Semantic subtyping of assignments needs to decide how to interpret intersections of functions
+    // CLI-116474 Semantic subtyping of assignments needs to decide how to interpret intersections of functions
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
+
     CheckResult result = check(R"(
         function f<a...,b...>()
             function g(x : ((number) -> number?) & ((unknown) -> string?))
@@ -939,9 +939,9 @@ could not be converted into
 
 TEST_CASE_FIXTURE(Fixture, "overloadeded_functions_with_overlapping_results_and_variadics")
 {
-    ScopedFastFlag dcr{
-        FFlag::LuauSolverV2, false
-    }; // CLI-116474 Semantic subtyping of assignments needs to decide how to interpret intersections of functions
+    // CLI-116474 Semantic subtyping of assignments needs to decide how to interpret intersections of functions
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
+
     CheckResult result = check(R"(
         function f(x : ((string?) -> (string | number)) & ((number?) -> ...number))
             local y : ((nil) -> (number, number?)) = x -- OK

tests/TypeInfer.loops.test.cpp

@@ -152,7 +152,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "for_in_loop")
 TEST_CASE_FIXTURE(BuiltinsFixture, "for_in_loop_with_next")
 {
     // CLI-116494 The generics K and V are leaking out of the next() function somehow.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local n
@@ -270,7 +270,7 @@ TEST_CASE_FIXTURE(Fixture, "for_in_loop_on_error")
 TEST_CASE_FIXTURE(Fixture, "for_in_loop_on_non_function")
 {
     // We report a spuriouus duplicate error here.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local bad_iter = 5
@@ -287,7 +287,7 @@ TEST_CASE_FIXTURE(Fixture, "for_in_loop_on_non_function")
 TEST_CASE_FIXTURE(BuiltinsFixture, "for_in_loop_error_on_factory_not_returning_the_right_amount_of_values")
 {
     // Spurious duplicate errors
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local function hasDivisors(value: number, table)
@@ -339,7 +339,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "for_in_loop_error_on_factory_not_returning_t
 TEST_CASE_FIXTURE(BuiltinsFixture, "for_in_loop_error_on_iterator_requiring_args_but_none_given")
 {
     // CLI-116496
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function prime_iter(state, index)
@@ -757,7 +757,7 @@ TEST_CASE_FIXTURE(Fixture, "loop_iter_basic")
 TEST_CASE_FIXTURE(Fixture, "loop_iter_trailing_nil")
 {
     // CLI-116498 Sometimes you can iterate over tables with no indexers.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local t: {string} = {}
@@ -774,9 +774,7 @@ TEST_CASE_FIXTURE(Fixture, "loop_iter_trailing_nil")
 TEST_CASE_FIXTURE(Fixture, "loop_iter_no_indexer_strict")
 {
     // CLI-116498 Sometimes you can iterate over tables with no indexers.
-    ScopedFastFlag sff[] = {
-        {FFlag::LuauSolverV2, false},
-    };
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local t = {}
@@ -1082,7 +1080,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "dcr_iteration_on_never_gives_never")
 TEST_CASE_FIXTURE(BuiltinsFixture, "iterate_over_properties")
 {
     // CLI-116498 - Sometimes you can iterate over tables with no indexer.
-    ScopedFastFlag sff0{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local function f()

tests/TypeInfer.modules.test.cpp

@@ -11,8 +11,9 @@
 #include "doctest.h"
 
 LUAU_FASTFLAG(LuauInstantiateInSubtyping)
+LUAU_FASTFLAG(LuauRequireCyclesDontAlwaysReturnAny)
 LUAU_FASTFLAG(LuauSolverV2)
-LUAU_FASTFLAG(LuauTypestateBuiltins)
+LUAU_FASTFLAG(LuauTypestateBuiltins2)
 
 using namespace Luau;
 
@@ -184,7 +185,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "cross_module_table_freeze")
     ModulePtr b = frontend.moduleResolver.getModule("game/B");
     REQUIRE(b != nullptr);
     // confirm that no cross-module mutation happened here!
-    if (FFlag::LuauSolverV2 && FFlag::LuauTypestateBuiltins)
+    if (FFlag::LuauSolverV2 && FFlag::LuauTypestateBuiltins2)
         CHECK(toString(b->returnType) == "{ read a: number }");
     else if (FFlag::LuauSolverV2)
         CHECK(toString(b->returnType) == "{ a: number }");
@@ -736,4 +737,45 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "spooky_blocked_type_laundered_by_bound_type"
     )"));
 }
 
+TEST_CASE_FIXTURE(BuiltinsFixture, "cycles_dont_make_everything_any")
+{
+    ScopedFastFlag sff{FFlag::LuauRequireCyclesDontAlwaysReturnAny, true};
+
+    fileResolver.source["game/A"] = R"(
+        --!strict
+        local module = {}
+
+        function module.foo()
+            return 2
+        end
+
+        function module.bar()
+            local m = require(game.B)
+            return m.foo() + 1
+        end
+
+        return module
+    )";
+
+    fileResolver.source["game/B"] = R"(
+        --!strict
+        local module = {}
+
+        function module.foo()
+            return 2
+        end
+
+        function module.bar()
+            local m = require(game.A)
+            return m.foo() + 1
+        end
+
+        return module
+    )";
+
+    frontend.check("game/A");
+
+    CHECK("module" == toString(frontend.moduleResolver.getModule("game/B")->returnType));
+}
+
 TEST_SUITE_END();

tests/TypeInfer.oop.test.cpp

@@ -19,7 +19,7 @@ TEST_SUITE_BEGIN("TypeInferOOP");
 TEST_CASE_FIXTURE(Fixture, "dont_suggest_using_colon_rather_than_dot_if_not_defined_with_colon")
 {
     // CLI-116571 method calls are missing arity checking?
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local someTable = {}
@@ -37,7 +37,7 @@ TEST_CASE_FIXTURE(Fixture, "dont_suggest_using_colon_rather_than_dot_if_not_defi
 TEST_CASE_FIXTURE(Fixture, "dont_suggest_using_colon_rather_than_dot_if_it_wont_help_2")
 {
     // CLI-116571 method calls are missing arity checking?
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local someTable = {}

tests/TypeInfer.operators.test.cpp

@@ -17,6 +17,7 @@
 using namespace Luau;
 
 LUAU_FASTFLAG(LuauSolverV2)
+LUAU_FASTFLAG(LuauMetatableFollow)
 
 TEST_SUITE_BEGIN("TypeInferOperators");
 
@@ -630,7 +631,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "typecheck_unary_minus_error")
 TEST_CASE_FIXTURE(BuiltinsFixture, "typecheck_unary_len_error")
 {
     // CLI-116463
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         --!strict
@@ -884,7 +885,7 @@ TEST_CASE_FIXTURE(Fixture, "error_on_invalid_operand_types_to_relational_operato
 TEST_CASE_FIXTURE(Fixture, "cli_38355_recursive_union")
 {
     // There's an extra spurious warning here when the new solver is enabled.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         --!strict
@@ -1425,7 +1426,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "luau_polyfill_is_array_simplified")
 TEST_CASE_FIXTURE(BuiltinsFixture, "luau_polyfill_is_array")
 {
     // CLI-116480 Subtyping bug: table should probably be a subtype of {[unknown]: unknown}
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 --!strict
@@ -1611,4 +1612,28 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "compound_operator_on_upvalue")
     LUAU_REQUIRE_NO_ERRORS(result);
 }
 
+TEST_CASE_FIXTURE(BuiltinsFixture, "metatable_operator_follow")
+{
+    ScopedFastFlag luauMetatableFollow{FFlag::LuauMetatableFollow, true};
+
+    CheckResult result = check(R"(
+local t1 = {}
+local t2 = {}
+local mt = {}
+
+mt.__eq = function(a, b)
+    return false
+end
+
+setmetatable(t1, mt)
+setmetatable(t2, mt)
+
+if t1 == t2 then
+
+end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+}
+
 TEST_SUITE_END();

tests/TypeInfer.provisional.test.cpp

@@ -73,7 +73,7 @@ TEST_CASE_FIXTURE(Fixture, "typeguard_inference_incomplete")
 
 TEST_CASE_FIXTURE(BuiltinsFixture, "luau-polyfill.Array.filter")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     // This test exercises the fact that we should reduce sealed/unsealed/free tables
     // res is a unsealed table with type {((T & ~nil)?) & any}
@@ -172,7 +172,7 @@ TEST_CASE_FIXTURE(Fixture, "it_should_be_agnostic_of_actual_size")
 // For now, infer it as just a free table.
 TEST_CASE_FIXTURE(BuiltinsFixture, "setmetatable_constrains_free_type_into_free_table")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local a = {}
@@ -192,7 +192,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "setmetatable_constrains_free_type_into_free_
 // Luau currently doesn't yet know how to allow assignments when the binding was refined.
 TEST_CASE_FIXTURE(Fixture, "while_body_are_also_refined")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         type Node<T> = { value: T, child: Node<T>? }
@@ -217,7 +217,7 @@ TEST_CASE_FIXTURE(Fixture, "while_body_are_also_refined")
 // We should be type checking the metamethod at the call site of setmetatable.
 TEST_CASE_FIXTURE(BuiltinsFixture, "error_on_eq_metamethod_returning_a_type_other_than_boolean")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local tab = {a = 1}
@@ -390,11 +390,9 @@ TEST_CASE_FIXTURE(Fixture, "specialization_binds_with_prototypes_too_early")
 
 TEST_CASE_FIXTURE(Fixture, "weird_fail_to_unify_type_pack")
 {
-    ScopedFastFlag sff[] = {
-        // I'm not sure why this is broken without DCR, but it seems to be fixed
-        // when DCR is enabled.
-        {FFlag::LuauSolverV2, false},
-    };
+    // I'm not sure why this is broken without DCR, but it seems to be fixed
+    // when DCR is enabled.
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local function f() return end
@@ -517,7 +515,7 @@ TEST_CASE_FIXTURE(Fixture, "dcr_can_partially_dispatch_a_constraint")
 
 TEST_CASE_FIXTURE(Fixture, "free_options_cannot_be_unified_together")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     TypeArena arena;
     TypeId nilType = builtinTypes->nilType;
@@ -553,7 +551,7 @@ TEST_CASE_FIXTURE(Fixture, "free_options_cannot_be_unified_together")
 
 TEST_CASE_FIXTURE(BuiltinsFixture, "for_in_loop_with_zero_iterators")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function no_iter() end
@@ -847,7 +845,7 @@ Type 'number?' could not be converted into 'number' in an invariant context)";
 
 TEST_CASE_FIXTURE(BuiltinsFixture, "table_insert_with_a_singleton_argument")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local function foo(t, x)
@@ -921,7 +919,7 @@ TEST_CASE_FIXTURE(Fixture, "expected_type_should_be_a_helpful_deduction_guide_fo
 
 TEST_CASE_FIXTURE(Fixture, "floating_generics_should_not_be_allowed")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local assign : <T, U, V, W>(target: T, source0: U?, source1: V?, source2: W?, ...any) -> T & U & V & W = (nil :: any)
@@ -945,7 +943,7 @@ TEST_CASE_FIXTURE(Fixture, "floating_generics_should_not_be_allowed")
 
 TEST_CASE_FIXTURE(Fixture, "free_options_can_be_unified_together")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     TypeArena arena;
     TypeId nilType = builtinTypes->nilType;
@@ -992,7 +990,7 @@ TEST_CASE_FIXTURE(Fixture, "unify_more_complex_unions_that_include_nil")
 
 TEST_CASE_FIXTURE(Fixture, "optional_class_instances_are_invariant_old_solver")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     createSomeClasses(&frontend);
 
@@ -1076,7 +1074,7 @@ end
 TEST_CASE_FIXTURE(BuiltinsFixture, "table_unification_infinite_recursion")
 {
     // The new solver doesn't recurse as heavily in this situation.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
 #if defined(_NOOPT) || defined(_DEBUG)
     ScopedFastInt LuauTypeInferRecursionLimit{FInt::LuauTypeInferRecursionLimit, 100};

tests/TypeInfer.refinements.test.cpp

@@ -1375,7 +1375,7 @@ TEST_CASE_FIXTURE(RefinementClassFixture, "discriminate_from_isa_of_x")
 TEST_CASE_FIXTURE(RefinementClassFixture, "typeguard_cast_free_table_to_vector")
 {
     // CLI-115286 - Refining via type(x) == 'vector' does not work in the new solver
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local function f(vec)
@@ -1569,7 +1569,7 @@ TEST_CASE_FIXTURE(RefinementClassFixture, "isa_type_refinement_must_be_known_ahe
 {
     // CLI-115087 - The new solver does not consistently combine tables with
     // class types when they appear in the upper bounds of a free type.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local function f(x): Instance

tests/TypeInfer.singletons.test.cpp

@@ -153,7 +153,7 @@ TEST_CASE_FIXTURE(Fixture, "overloaded_function_call_with_singletons")
 
 TEST_CASE_FIXTURE(Fixture, "overloaded_function_call_with_singletons_mismatch")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function f(g: ((true, string) -> ()) & ((false, number) -> ()))
@@ -463,7 +463,7 @@ local a: Animal = if true then { tag = 'cat', catfood = 'something' } else { tag
 
 TEST_CASE_FIXTURE(Fixture, "widen_the_supertype_if_it_is_free_and_subtype_has_singleton")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local function foo(f, x)
@@ -483,7 +483,7 @@ TEST_CASE_FIXTURE(Fixture, "widen_the_supertype_if_it_is_free_and_subtype_has_si
 
 TEST_CASE_FIXTURE(Fixture, "return_type_of_f_is_not_widened")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local function foo(f, x): "hello"? -- anyone there?

tests/TypeInfer.tables.test.cpp

@@ -19,6 +19,7 @@ LUAU_FASTFLAG(LuauSolverV2)
 LUAU_FASTFLAG(LuauInstantiateInSubtyping)
 LUAU_FASTFLAG(LuauFixIndexerSubtypingOrdering)
 LUAU_FASTFLAG(LuauAcceptIndexingTableUnionsIntersections)
+LUAU_FASTFLAG(LuauRetrySubtypingWithoutHiddenPack)
 
 LUAU_DYNAMIC_FASTINT(LuauTypeSolverRelease)
 
@@ -318,7 +319,7 @@ TEST_CASE_FIXTURE(Fixture, "call_method_with_explicit_self_argument")
 TEST_CASE_FIXTURE(Fixture, "used_dot_instead_of_colon")
 {
     // CLI-114792 Dot vs colon warnings aren't in the new solver yet.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local T = {}
@@ -371,7 +372,7 @@ TEST_CASE_FIXTURE(Fixture, "used_dot_instead_of_colon_but_correctly")
 TEST_CASE_FIXTURE(Fixture, "used_colon_instead_of_dot")
 {
     // CLI-114792 Dot vs colon warnings aren't in the new solver yet.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local T = {}
@@ -396,7 +397,7 @@ TEST_CASE_FIXTURE(Fixture, "used_colon_instead_of_dot")
 TEST_CASE_FIXTURE(Fixture, "open_table_unification_2")
 {
     // CLI-114792 We don't report MissingProperties in many places where the old solver does.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local a = {}
@@ -536,7 +537,7 @@ TEST_CASE_FIXTURE(Fixture, "table_param_width_subtyping_3")
 TEST_CASE_FIXTURE(Fixture, "table_unification_4")
 {
     // CLI-114134 - Use egraphs to simplify types better.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function foo(o)
@@ -567,7 +568,7 @@ TEST_CASE_FIXTURE(Fixture, "ok_to_add_property_to_free_table")
 TEST_CASE_FIXTURE(Fixture, "okay_to_add_property_to_unsealed_tables_by_assignment")
 {
     // CLI-114872
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         --!strict
@@ -586,7 +587,7 @@ TEST_CASE_FIXTURE(Fixture, "okay_to_add_property_to_unsealed_tables_by_assignmen
 TEST_CASE_FIXTURE(Fixture, "okay_to_add_property_to_unsealed_tables_by_function_call")
 {
     // CLI-114873
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         --!strict
@@ -811,7 +812,7 @@ TEST_CASE_FIXTURE(Fixture, "infer_indexer_from_value_property_in_literal")
 TEST_CASE_FIXTURE(Fixture, "infer_indexer_from_its_variable_type_and_unifiable")
 {
     // This code is totally different in the new solver.  We instead create a new type state for t2.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local t1: { [string]: string } = {}
@@ -893,7 +894,7 @@ TEST_CASE_FIXTURE(Fixture, "sealed_table_value_can_infer_an_indexer")
 
 TEST_CASE_FIXTURE(Fixture, "array_factory_function")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function empty() return {} end
@@ -930,7 +931,7 @@ TEST_CASE_FIXTURE(Fixture, "indexer_on_sealed_table_must_unify_with_free_table")
     // CLI-114134 What should be happening here is that the type of `t` should
     // be reduced from `{number} & {string}` to `never`, but that's not
     // happening.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function F(t): {number}
@@ -993,7 +994,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "indexing_from_a_table_should_prefer_properti
 
 TEST_CASE_FIXTURE(Fixture, "any_when_indexing_into_an_unsealed_table_with_no_indexer_in_nonstrict_mode")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         --!nonstrict
@@ -1145,7 +1146,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "meta_add_inferred")
 
 TEST_CASE_FIXTURE(BuiltinsFixture, "meta_add_both_ways")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         type VectorMt = { __add: (Vector, number) -> Vector }
@@ -1523,7 +1524,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "found_multiple_like_keys")
 TEST_CASE_FIXTURE(BuiltinsFixture, "dont_suggest_exact_match_keys")
 {
     // CLI-114977 Unsealed table writes don't account for order properly
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local t = {}
@@ -1566,7 +1567,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "getmetatable_returns_pointer_to_metatable")
 TEST_CASE_FIXTURE(BuiltinsFixture, "metatable_mismatch_should_fail")
 {
     // This test is invalid because we now create a new type state for t1 at the assignment.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local t1 = {x = 1}
@@ -1610,7 +1611,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "property_lookup_through_tabletypevar_metatab
 TEST_CASE_FIXTURE(BuiltinsFixture, "missing_metatable_for_sealed_tables_do_not_get_inferred")
 {
     // This test is invalid because we now create a new type state for t at the assignment.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local t = {x = 1}
@@ -1665,7 +1666,7 @@ TEST_CASE_FIXTURE(Fixture, "right_table_missing_key")
 TEST_CASE_FIXTURE(Fixture, "right_table_missing_key2")
 {
     // CLI-114792 We don't report MissingProperties
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function f(t: {}): { [string]: string, a: string }
@@ -1927,7 +1928,7 @@ TEST_CASE_FIXTURE(Fixture, "type_mismatch_on_massive_table_is_cut_short")
 TEST_CASE_FIXTURE(Fixture, "ok_to_set_nil_even_on_non_lvalue_base_expr")
 {
     // CLI-100076 Assigning nil to an indexer should always succeed
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local function f(): { [string]: number }
@@ -2096,7 +2097,7 @@ local Test: {Table} = {
 TEST_CASE_FIXTURE(Fixture, "common_table_element_general")
 {
     // CLI-115275 - Bidirectional inference does not always propagate indexer types into the expression
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         type Table = {
@@ -2218,7 +2219,7 @@ foo({
 TEST_CASE_FIXTURE(Fixture, "common_table_element_union_in_call_tail")
 {
     // CLI-115239 - Bidirectional checking does not work for __call metamethods
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         type Foo = {x: number | string}
@@ -2265,7 +2266,16 @@ TEST_CASE_FIXTURE(Fixture, "invariant_table_properties_means_instantiating_table
         local c : string = t.m("hi")
     )");
 
-    if (FFlag::LuauSolverV2)
+    if (FFlag::LuauSolverV2 && FFlag::LuauRetrySubtypingWithoutHiddenPack)
+    {
+        LUAU_REQUIRE_ERROR_COUNT(1, result);
+
+        CHECK(get<ExplicitFunctionAnnotationRecommended>(result.errors[0]));
+
+        // This is not actually the expected behavior, but the typemismatch we were seeing before was for the wrong reason.
+        // The behavior of this test is just regressed generally in the new solver, and will need to be consciously addressed.
+    }
+    else if (FFlag::LuauSolverV2)
     {
         LUAU_REQUIRE_ERROR_COUNT(2, result);
 
@@ -2504,7 +2514,7 @@ Type 'number' could not be converted into 'string' in an invariant context)";
 TEST_CASE_FIXTURE(Fixture, "explicitly_typed_table")
 {
     // Table properties like HasSuper.p must be invariant.  The new solver rightly rejects this program.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 --!strict
@@ -2554,7 +2564,7 @@ Table type '{ x: number, y: number }' not compatible with type 'Super' because t
 TEST_CASE_FIXTURE(Fixture, "explicitly_typed_table_with_indexer")
 {
     // CLI-114791 Bidirectional inference should be able to cause the inference engine to forget that a table literal has some property
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         --!strict
@@ -2572,7 +2582,7 @@ TEST_CASE_FIXTURE(Fixture, "explicitly_typed_table_with_indexer")
 TEST_CASE_FIXTURE(BuiltinsFixture, "recursive_metatable_type_call")
 {
     // CLI-114782
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 local b
@@ -2827,7 +2837,7 @@ TEST_CASE_FIXTURE(Fixture, "table_length")
 TEST_CASE_FIXTURE(Fixture, "nil_assign_doesnt_hit_indexer")
 {
     // CLI-100076 - Assigning a table key to `nil` in the presence of an indexer should always be permitted
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check("local a = {} a[0] = 7  a[0] = nil");
     LUAU_REQUIRE_ERROR_COUNT(0, result);
@@ -3296,7 +3306,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "table_call_metamethod_generic")
 TEST_CASE_FIXTURE(BuiltinsFixture, "table_simple_call")
 {
     // The new solver can see that this function is safe to oversaturate.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local a = setmetatable({ x = 2 }, {
@@ -3589,7 +3599,7 @@ local b = a.x
 TEST_CASE_FIXTURE(Fixture, "scalar_is_a_subtype_of_a_compatible_polymorphic_shape_type")
 {
     // CLI-115087 The new solver cannot infer that a table-like type is actually string
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local function f(s)
@@ -3678,7 +3688,7 @@ Table type 'typeof(string)' not compatible with type 't1 where t1 = {- absolutel
 TEST_CASE_FIXTURE(Fixture, "a_free_shape_can_turn_into_a_scalar_if_it_is_compatible")
 {
     // CLI-115087 The new solver cannot infer that a table-like type is actually string
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local function f(s): string
@@ -3733,7 +3743,7 @@ Table type 'typeof(string)' not compatible with type 't1 where t1 = {+ absolutel
 TEST_CASE_FIXTURE(BuiltinsFixture, "a_free_shape_can_turn_into_a_scalar_directly")
 {
     // We need egraphs to simplify the type of `out` here.  CLI-114134
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local function stringByteList(str)
@@ -4231,9 +4241,7 @@ TEST_CASE_FIXTURE(Fixture, "identify_all_problematic_table_fields")
 
 TEST_CASE_FIXTURE(Fixture, "read_and_write_only_table_properties_are_unsupported")
 {
-    ScopedFastFlag sff[] = {
-        {FFlag::LuauSolverV2, false},
-    };
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         type W = {read x: number}
@@ -4370,7 +4378,7 @@ TEST_CASE_FIXTURE(Fixture, "write_annotations_are_unsupported_even_with_the_new_
 
 TEST_CASE_FIXTURE(Fixture, "read_and_write_only_table_properties_are_unsupported")
 {
-    ScopedFastFlag sff[] = {{FFlag::LuauSolverV2, false}};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         type W = {read x: number}
@@ -4394,7 +4402,7 @@ TEST_CASE_FIXTURE(Fixture, "read_and_write_only_table_properties_are_unsupported
 
 TEST_CASE_FIXTURE(Fixture, "read_ond_write_only_indexers_are_unsupported")
 {
-    ScopedFastFlag sff[] = {{FFlag::LuauSolverV2, false}};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         type T = {read [string]: number}

tests/TypeInfer.test.cpp

@@ -146,9 +146,7 @@ TEST_CASE_FIXTURE(Fixture, "infer_locals_via_assignment_from_its_call_site")
 
 TEST_CASE_FIXTURE(Fixture, "infer_in_nocheck_mode")
 {
-    ScopedFastFlag sff[]{
-        {FFlag::LuauSolverV2, false},
-    };
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         --!nocheck
@@ -225,7 +223,7 @@ TEST_CASE_FIXTURE(Fixture, "statements_are_topologically_sorted")
 
 TEST_CASE_FIXTURE(Fixture, "unify_nearly_identical_recursive_types")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local o
@@ -266,7 +264,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "weird_case")
 
 TEST_CASE_FIXTURE(Fixture, "dont_ice_when_failing_the_occurs_check")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         --!strict
@@ -385,7 +383,7 @@ TEST_CASE_FIXTURE(Fixture, "exponential_blowup_from_copying_types")
 // checker. We also want it to somewhat match up with production values, so we push up the parser recursion limit a little bit instead.
 TEST_CASE_FIXTURE(Fixture, "check_type_infer_recursion_count")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
 #if defined(LUAU_ENABLE_ASAN)
     int limit = 250;
@@ -443,7 +441,7 @@ TEST_CASE_FIXTURE(Fixture, "check_expr_recursion_limit")
 TEST_CASE_FIXTURE(Fixture, "globals")
 {
     // The new solver does not permit assignments to globals like this.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         --!nonstrict
@@ -457,7 +455,7 @@ TEST_CASE_FIXTURE(Fixture, "globals")
 
 TEST_CASE_FIXTURE(Fixture, "globals2")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         --!nonstrict
@@ -507,7 +505,7 @@ TEST_CASE_FIXTURE(Fixture, "correctly_scope_locals_do")
 
 TEST_CASE_FIXTURE(Fixture, "checking_should_not_ice")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CHECK_NOTHROW(check(R"(
         --!nonstrict
@@ -601,7 +599,7 @@ TEST_CASE_FIXTURE(Fixture, "tc_after_error_recovery_no_assert")
 TEST_CASE_FIXTURE(BuiltinsFixture, "tc_after_error_recovery_no_replacement_name_in_error")
 {
     {
-        ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+        DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
         CheckResult result = check(R"(
             --!strict
@@ -623,7 +621,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "tc_after_error_recovery_no_replacement_name_
     }
 
     {
-        ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+        DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
         CheckResult result = check(R"(
             --!strict
@@ -698,7 +696,7 @@ TEST_CASE_FIXTURE(Fixture, "cli_39932_use_unifier_in_ensure_methods")
 
 TEST_CASE_FIXTURE(Fixture, "dont_report_type_errors_within_an_AstStatError")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         foo
@@ -709,7 +707,7 @@ TEST_CASE_FIXTURE(Fixture, "dont_report_type_errors_within_an_AstStatError")
 
 TEST_CASE_FIXTURE(Fixture, "dont_report_type_errors_within_an_AstExprError")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local a = foo:
@@ -1100,7 +1098,7 @@ end
 
 TEST_CASE_FIXTURE(Fixture, "cli_50041_committing_txnlog_in_apollo_client_error")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         --!strict
@@ -1223,7 +1221,7 @@ TEST_CASE_FIXTURE(Fixture, "type_infer_cache_limit_normalizer")
 TEST_CASE_FIXTURE(Fixture, "follow_on_new_types_in_substitution")
 {
     // CLI-114134
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local obj = {}
@@ -1564,7 +1562,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "lti_must_record_contributing_locations")
  */
 TEST_CASE_FIXTURE(BuiltinsFixture, "be_sure_to_use_active_txnlog_when_evaluating_a_variadic_overload")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local function concat<T>(target: {T}, ...: {T} | T): {T}

tests/TypeInfer.tryUnify.test.cpp

@@ -17,7 +17,7 @@ LUAU_FASTFLAG(LuauUnifierRecursionOnRestart);
 struct TryUnifyFixture : Fixture
 {
     // Cannot use `TryUnifyFixture` under DCR.
-    ScopedFastFlag noDcr{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     TypeArena arena;
     ScopePtr globalScope{new Scope{arena.addTypePack({TypeId{}})}};
@@ -154,7 +154,7 @@ TEST_CASE_FIXTURE(Fixture, "uninhabited_intersection_sub_anything")
 
 TEST_CASE_FIXTURE(Fixture, "uninhabited_table_sub_never")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function f(arg : { prop : string & number }) : never
@@ -166,7 +166,7 @@ TEST_CASE_FIXTURE(Fixture, "uninhabited_table_sub_never")
 
 TEST_CASE_FIXTURE(Fixture, "uninhabited_table_sub_anything")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function f(arg : { prop : string & number }) : boolean
@@ -178,7 +178,7 @@ TEST_CASE_FIXTURE(Fixture, "uninhabited_table_sub_anything")
 
 TEST_CASE_FIXTURE(Fixture, "members_of_failed_typepack_unification_are_unified_with_errorType")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function f(arg: number) end
@@ -195,7 +195,7 @@ TEST_CASE_FIXTURE(Fixture, "members_of_failed_typepack_unification_are_unified_w
 
 TEST_CASE_FIXTURE(Fixture, "result_of_failed_typepack_unification_is_constrained")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function f(arg: number) return arg end

tests/TypeInfer.typePacks.test.cpp

@@ -787,7 +787,7 @@ local d: Y<number, string, ...boolean, ...() -> ()>
 
 TEST_CASE_FIXTURE(Fixture, "type_alias_default_type_errors")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         type Y<T = T> = { a: T }
@@ -811,7 +811,7 @@ TEST_CASE_FIXTURE(Fixture, "type_alias_default_type_errors2")
 
 TEST_CASE_FIXTURE(Fixture, "type_alias_default_type_errors3")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         type Y<T = string, U... = ...string> = { a: (T) -> U... }
@@ -824,7 +824,7 @@ TEST_CASE_FIXTURE(Fixture, "type_alias_default_type_errors3")
 
 TEST_CASE_FIXTURE(Fixture, "type_alias_default_type_errors4")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         type Packed<T> = (T) -> T
@@ -1065,7 +1065,7 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "detect_cyclic_typepacks2")
 
 TEST_CASE_FIXTURE(Fixture, "unify_variadic_tails_in_arguments")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function foo(...: string): number

tests/TypeInfer.unionTypes.test.cpp

@@ -36,7 +36,7 @@ TEST_CASE_FIXTURE(Fixture, "return_types_can_be_disjoint")
 {
     // CLI-114134 We need egraphs to consistently reduce the cyclic union
     // introduced by the increment here.
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local count = 0
@@ -122,7 +122,7 @@ TEST_CASE_FIXTURE(Fixture, "optional_arguments")
 TEST_CASE_FIXTURE(Fixture, "optional_arguments_table")
 {
     // CLI-115588 - Bidirectional inference does not happen for assignments
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         local a:{a:string, b:string?}
@@ -478,7 +478,7 @@ end
 
 TEST_CASE_FIXTURE(Fixture, "unify_unsealed_table_union_check")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
 local x = { x = 3 }
@@ -653,7 +653,7 @@ TEST_CASE_FIXTURE(Fixture, "indexing_into_a_cyclic_union_doesnt_crash")
 
 TEST_CASE_FIXTURE(BuiltinsFixture, "table_union_write_indirect")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         type A = { x: number, y: (number) -> string } | { z: number, y: (number) -> string }
@@ -729,7 +729,7 @@ TEST_CASE_FIXTURE(Fixture, "union_of_generic_typepack_functions")
 
 TEST_CASE_FIXTURE(Fixture, "union_of_functions_mentioning_generics")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function f<a,b>()
@@ -749,7 +749,7 @@ TEST_CASE_FIXTURE(Fixture, "union_of_functions_mentioning_generics")
 
 TEST_CASE_FIXTURE(Fixture, "union_of_functions_mentioning_generic_typepacks")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function f<a...>()
@@ -770,7 +770,7 @@ could not be converted into
 
 TEST_CASE_FIXTURE(Fixture, "union_of_functions_with_mismatching_arg_arities")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function f(x : (number) -> number?)
@@ -789,7 +789,7 @@ could not be converted into
 
 TEST_CASE_FIXTURE(Fixture, "union_of_functions_with_mismatching_result_arities")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function f(x : () -> (number | string))
@@ -808,7 +808,7 @@ could not be converted into
 
 TEST_CASE_FIXTURE(Fixture, "union_of_functions_with_variadics")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function f(x : (...nil) -> (...number?))
@@ -854,7 +854,7 @@ could not be converted into
 
 TEST_CASE_FIXTURE(Fixture, "union_of_functions_with_mismatching_result_variadics")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function f(x : () -> (number?, ...number))
@@ -922,7 +922,7 @@ TEST_CASE_FIXTURE(Fixture, "union_table_any_property")
 
 TEST_CASE_FIXTURE(Fixture, "union_function_any_args")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function f(sup : ((...any) -> (...any))?, sub : ((number) -> (...any)))
@@ -946,7 +946,7 @@ TEST_CASE_FIXTURE(Fixture, "optional_any")
 
 TEST_CASE_FIXTURE(Fixture, "generic_function_with_optional_arg")
 {
-    ScopedFastFlag sff{FFlag::LuauSolverV2, false};
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CheckResult result = check(R"(
         function f<T>(x : T?) : {T}

tests/TypePath.test.cpp

@@ -538,9 +538,7 @@ TEST_SUITE_BEGIN("TypePathToString");
 
 TEST_CASE("field")
 {
-    ScopedFastFlag sff[] = {
-        {FFlag::LuauSolverV2, false},
-    };
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     CHECK(toString(PathBuilder().prop("foo").build()) == R"(["foo"])");
 }
@@ -567,9 +565,7 @@ TEST_CASE("empty_path")
 
 TEST_CASE("prop")
 {
-    ScopedFastFlag sff[] = {
-        {FFlag::LuauSolverV2, false},
-    };
+    DOES_NOT_PASS_NEW_SOLVER_GUARD();
 
     Path p = PathBuilder().prop("foo").build();
     CHECK(p == Path(TypePath::Property{"foo"}));

tests/conformance/debug.lua

@@ -138,4 +138,17 @@ end)
 
 coroutine.resume(wrapped2)
 
+local wrapped3 = coroutine.create(function()
+	local thread = coroutine.create(function(target)
+		for i = 1, 100 do pcall(debug.info, target, 0, "?f") end
+		return 123
+	end)
+
+	local success, res = coroutine.resume(thread, coroutine.running())
+	assert(success)
+	assert(res == 123)
+end)
+
+coroutine.resume(wrapped3)
+
 return 'OK'

tests/conformance/vector_library.lua

@@ -0,0 +1,159 @@
+-- This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
+print('testing vector library')
+
+function ecall(fn, ...)
+    local ok, err = pcall(fn, ...)
+    assert(not ok)
+    return err:sub((err:find(": ") or -1) + 2, #err)
+end
+
+-- make sure we cover both builtin and C impl
+assert(vector.create(1, 2, 4) == vector.create("1", "2", "4"))
+
+-- testing 'dot' with error handling and different call kinds to mostly check details in the codegen
+assert(vector.dot(vector.create(1, 2, 4), vector.create(5, 6, 7)) == 45)
+assert(ecall(function() vector.dot(vector.create(1, 2, 4)) end) == "missing argument #2 to 'dot' (vector expected)")
+assert(ecall(function() vector.dot(vector.create(1, 2, 4), 2) end) == "invalid argument #2 to 'dot' (vector expected, got number)")
+
+local function doDot1(a: vector, b)
+    return vector.dot(a, b)
+end
+
+local function doDot2(a: vector, b)
+    return (vector.dot(a, b))
+end
+
+local v124 = vector.create(1, 2, 4)
+
+assert(doDot1(v124, vector.create(5, 6, 7)) == 45)
+assert(doDot2(v124, vector.create(5, 6, 7)) == 45)
+assert(ecall(function() doDot1(v124, "a") end) == "invalid argument #2 to 'dot' (vector expected, got string)")
+assert(ecall(function() doDot2(v124, "a") end) == "invalid argument #2 to 'dot' (vector expected, got string)")
+assert(select("#", doDot1(v124, vector.create(5, 6, 7))) == 1)
+assert(select("#", doDot2(v124, vector.create(5, 6, 7))) == 1)
+
+-- 'cross' tests and next ones will only test basic results
+assert(vector.cross(vector.create(1, 0, 0), vector.create(0, 1, 0)) == vector.create(0, 0, 1))
+assert(vector.cross(vector.create(0, 1, 0), vector.create(1, 0, 0)) == vector.create(0, 0, -1))
+assert(select("#", vector.cross(vector.zero, vector.one)) == 1)
+
+-- 'normalize'
+assert(vector.normalize(vector.create(0.5, 0, 0)) == vector.create(1, 0, 0))
+assert(select("#", vector.normalize(vector.one)) == 1)
+
+-- 'magnitude'
+assert(vector.magnitude(vector.create(1, 2, 2)) == 3)
+assert(select("#", vector.magnitude(vector.one)) == 1)
+
+-- 'abs'
+assert(vector.abs(-vector.one) == vector.one)
+assert(vector.abs(vector.create(math.huge, 0, 0)).x == math.abs(math.huge))
+assert(vector.abs(vector.create(0/0, 0, 0)).x ~= 0/0)
+assert(select("#", vector.abs(vector.one)) == 1)
+
+-- 'floor'
+assert(vector.floor(vector.create(1, 2, 3)) == vector.create(1, 2, 3))
+assert(vector.floor(vector.create(1.5, 2.4, 3)) == vector.create(1, 2, 3))
+assert(vector.floor(vector.create(-1.5, -2.4, -3)) == vector.create(-2, -3, -3))
+assert(select("#", vector.floor(vector.one)) == 1)
+
+-- 'ceil'
+assert(vector.ceil(vector.create(1, 2, 3)) == vector.create(1, 2, 3))
+assert(vector.ceil(vector.create(1.5, 2.4, 3)) == vector.create(2, 3, 3))
+assert(vector.ceil(vector.create(-1.5, -2.4, -3)) == vector.create(-1, -2, -3))
+assert(select("#", vector.ceil(vector.one)) == 1)
+
+-- 'sign'
+assert(vector.sign(vector.zero) == vector.zero)
+assert(vector.sign(vector.one) == vector.one)
+assert(vector.sign(vector.create(-10, 0, 10)) == vector.create(-1, 0, 1))
+assert(vector.sign(vector.create(math.huge, 0, -math.huge)) == vector.create(1, 0, -1))
+-- negative zero and nan are consistent with math library, even if implementation defined
+assert(vector.sign(vector.create(-0, 0, 0)).x == math.sign(-0))
+assert(vector.sign(vector.create(0/0, 0, 0)).x == math.sign(0/0))
+assert(select("#", vector.sign(vector.one)) == 1)
+
+-- 'angle'
+assert(math.abs(vector.angle(vector.create(1, 2, 3), vector.create(4, 5, 6)) - 0.2257259) < 0.00001)
+assert(select("#", vector.angle(vector.zero, vector.one)) == 1)
+assert(select("#", vector.angle(vector.one, -vector.one, vector.zero)) == 1)
+
+do
+    -- random (non-unit) vectors
+    local rand = {
+        vector.create(-1.05, -0.04, 1.06),
+        vector.create(-0.75, 1.71, 1.29),
+        vector.create(1.94, 0.76, -0.93),
+        vector.create(0.02, -1.58, 0.20),
+        vector.create(1.64, -0.76, -0.73),
+        vector.create(-2.44, 0.66, 1.06),
+        vector.create(-2.61, 1.01, 0.50),
+        vector.create(1.21, -2.28, -0.45),
+        vector.create(-0.31, -0.12, 1.96),
+        vector.create(1.16, -0.07, -1.93)
+    }
+
+    -- numeric answers to the tests below (in degrees)
+    local ans = {
+        -105.1702,
+        -69.49491,
+        0.0,
+        -102.9083,
+        0.0,
+        0.0,
+        180.0,
+        -0.02797646,
+        -90.0,
+        165.8858
+    }
+
+    for i,v in ans do
+        ans[i] = math.rad(ans[i])
+    end
+    
+    local function fuzzyeq(x, y, eps) return x == y or math.abs(x - y) < (eps or 1e-6) end
+
+    assert(fuzzyeq(vector.angle(rand[10], rand[1]), math.abs(ans[10])))
+    assert(fuzzyeq(vector.angle(rand[2], rand[3]), math.abs(ans[1])))
+    assert(fuzzyeq(vector.angle(rand[4], rand[5]), math.abs(ans[2])))
+    assert(fuzzyeq(vector.angle(vector.zero, rand[6]), math.abs(ans[3])))
+    assert(fuzzyeq(vector.angle(vector.one, rand[7]), math.abs(ans[4])))
+    assert(fuzzyeq(vector.angle(vector.zero, vector.zero), math.abs(ans[5])))
+    assert(fuzzyeq(vector.angle(rand[8], rand[8]), math.abs(ans[6])))
+    assert(fuzzyeq(vector.angle(-rand[8], rand[8]), math.abs(ans[7])))
+    assert(fuzzyeq(vector.angle(rand[9], rand[9] + vector.create(0, 1, 0) * 0.001), math.abs(ans[8]), 1e-3)) -- slightly more generous eps
+    assert(fuzzyeq(vector.angle(vector.create(1, 0, 0), vector.create(0, 1, 0)), math.abs(ans[9])))
+
+    assert(fuzzyeq(vector.angle(rand[10], rand[1], rand[2]), ans[10]))
+    assert(fuzzyeq(vector.angle(rand[2], rand[3], rand[4]), ans[1]))
+    assert(fuzzyeq(vector.angle(rand[4], rand[5], rand[5]), ans[2]))
+    assert(fuzzyeq(vector.angle(vector.zero, rand[6], rand[10]), ans[3]))
+    assert(fuzzyeq(vector.angle(vector.one, rand[7], rand[10]), ans[4]))
+    assert(fuzzyeq(vector.angle(vector.zero, vector.zero, vector.zero), ans[5]))
+    assert(fuzzyeq(vector.angle(rand[8], rand[8], rand[10]), ans[6]))
+    assert(fuzzyeq(vector.angle(rand[9], rand[9] + vector.create(0, 1, 0) * 0.001, rand[10]), ans[8], 1e-3)) -- slightly more generous eps
+    assert(fuzzyeq(vector.angle(vector.create(1, 0, 0), vector.create(0, 1, 0), rand[10]), ans[9]))
+end
+
+-- 'min'/'max'
+assert(vector.max(vector.create(-1, 2, 0.5)) == vector.create(-1, 2, 0.5))
+assert(vector.min(vector.create(-1, 2, 0.5)) == vector.create(-1, 2, 0.5))
+
+assert(ecall(function() vector.min() end) == "missing argument #1 to 'min' (vector expected)")
+assert(ecall(function() vector.max() end) == "missing argument #1 to 'max' (vector expected)")
+
+assert(select("#", vector.max(vector.zero, vector.one)) == 1)
+assert(select("#", vector.min(vector.zero, vector.one)) == 1)
+
+assert(vector.max(vector.create(-1, 2, 3), vector.create(3, 2, 1)) == vector.create(3, 2, 3))
+assert(vector.min(vector.create(-1, 2, 3), vector.create(3, 2, 1)) == vector.create(-1, 2, 1))
+
+assert(vector.max(vector.create(1, 2, 3),vector.create(2, 3, 4),vector.create(3, 4, 5),vector.create(4, 5, 6)) == vector.create(4, 5, 6))
+assert(vector.min(vector.create(1, 2, 3),vector.create(2, 3, 4),vector.create(3, 4, 5),vector.create(4, 5, 6)) == vector.create(1, 2, 3))
+
+-- clamp
+assert(vector.clamp(vector.create(1, 1, 1), vector.create(0, 1, 2), vector.create(3, 3, 3)) == vector.create(1, 1, 2))
+assert(vector.clamp(vector.create(1, 1, 1), vector.create(-1, -1, -1), vector.create(0, 1, 2)) == vector.create(0, 1, 1))
+assert(select("#", vector.clamp(vector.zero, vector.zero, vector.one)) == 1)
+
+return 'OK'