Sync to upstream/release/569 (#878)

All of our changes this week have been focused on the new type solver
and the JIT.

As we march toward feature parity with the old solver, we've tightened
up a bunch of lingering issues with overload resolution, unsealed
tables, and type normalization. We've also fixed a bunch of crashes and
assertion failures in the new solver.

On the JIT front, we've started work on an A64 backend, improved the IR
analysis in a bunch of cases, and implemented assembly generation for
the builtin functions `type()` and `typeof()`.

---------

Co-authored-by: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>

Analysis/include/Luau/Clone.h

@@ -26,7 +26,4 @@ TypePackId clone(TypePackId tp, TypeArena& dest, CloneState& cloneState);
 TypeId clone(TypeId tp, TypeArena& dest, CloneState& cloneState);
 TypeFun clone(const TypeFun& typeFun, TypeArena& dest, CloneState& cloneState);
 
-TypeId shallowClone(TypeId ty, TypeArena& dest, const TxnLog* log, bool alwaysClone = false);
-TypeId shallowClone(TypeId ty, NotNull<TypeArena> dest);
-
 } // namespace Luau

Analysis/include/Luau/ControlFlow.h

@@ -11,10 +11,10 @@ using ScopePtr = std::shared_ptr<Scope>;
 
 enum class ControlFlow
 {
-    None     = 0b00001,
-    Returns  = 0b00010,
-    Throws   = 0b00100,
-    Break    = 0b01000, // Currently unused.
+    None = 0b00001,
+    Returns = 0b00010,
+    Throws = 0b00100,
+    Break = 0b01000,    // Currently unused.
     Continue = 0b10000, // Currently unused.
 };
 

Analysis/include/Luau/Unifiable.h

@@ -82,7 +82,7 @@ namespace Luau::Unifiable
 using Name = std::string;
 
 int freshIndex();
-  
+
 struct Free
 {
     explicit Free(TypeLevel level);

Analysis/src/Clone.cpp

@@ -7,7 +7,7 @@
 #include "Luau/Unifiable.h"
 
 LUAU_FASTFLAG(DebugLuauCopyBeforeNormalizing)
-LUAU_FASTFLAG(LuauClonePublicInterfaceLess)
+LUAU_FASTFLAG(LuauClonePublicInterfaceLess2)
 
 LUAU_FASTINTVARIABLE(LuauTypeCloneRecursionLimit, 300)
 
@@ -422,86 +422,4 @@ TypeFun clone(const TypeFun& typeFun, TypeArena& dest, CloneState& cloneState)
     return result;
 }
 
-TypeId shallowClone(TypeId ty, TypeArena& dest, const TxnLog* log, bool alwaysClone)
-{
-    ty = log->follow(ty);
-
-    TypeId result = ty;
-
-    if (auto pty = log->pending(ty))
-        ty = &pty->pending;
-
-    if (const FunctionType* ftv = get<FunctionType>(ty))
-    {
-        FunctionType clone = FunctionType{ftv->level, ftv->scope, ftv->argTypes, ftv->retTypes, ftv->definition, ftv->hasSelf};
-        clone.generics = ftv->generics;
-        clone.genericPacks = ftv->genericPacks;
-        clone.magicFunction = ftv->magicFunction;
-        clone.dcrMagicFunction = ftv->dcrMagicFunction;
-        clone.dcrMagicRefinement = ftv->dcrMagicRefinement;
-        clone.tags = ftv->tags;
-        clone.argNames = ftv->argNames;
-        result = dest.addType(std::move(clone));
-    }
-    else if (const TableType* ttv = get<TableType>(ty))
-    {
-        LUAU_ASSERT(!ttv->boundTo);
-        TableType clone = TableType{ttv->props, ttv->indexer, ttv->level, ttv->scope, ttv->state};
-        clone.definitionModuleName = ttv->definitionModuleName;
-        clone.definitionLocation = ttv->definitionLocation;
-        clone.name = ttv->name;
-        clone.syntheticName = ttv->syntheticName;
-        clone.instantiatedTypeParams = ttv->instantiatedTypeParams;
-        clone.instantiatedTypePackParams = ttv->instantiatedTypePackParams;
-        clone.tags = ttv->tags;
-        result = dest.addType(std::move(clone));
-    }
-    else if (const MetatableType* mtv = get<MetatableType>(ty))
-    {
-        MetatableType clone = MetatableType{mtv->table, mtv->metatable};
-        clone.syntheticName = mtv->syntheticName;
-        result = dest.addType(std::move(clone));
-    }
-    else if (const UnionType* utv = get<UnionType>(ty))
-    {
-        UnionType clone;
-        clone.options = utv->options;
-        result = dest.addType(std::move(clone));
-    }
-    else if (const IntersectionType* itv = get<IntersectionType>(ty))
-    {
-        IntersectionType clone;
-        clone.parts = itv->parts;
-        result = dest.addType(std::move(clone));
-    }
-    else if (const PendingExpansionType* petv = get<PendingExpansionType>(ty))
-    {
-        PendingExpansionType clone{petv->prefix, petv->name, petv->typeArguments, petv->packArguments};
-        result = dest.addType(std::move(clone));
-    }
-    else if (const ClassType* ctv = get<ClassType>(ty); FFlag::LuauClonePublicInterfaceLess && ctv && alwaysClone)
-    {
-        ClassType clone{ctv->name, ctv->props, ctv->parent, ctv->metatable, ctv->tags, ctv->userData, ctv->definitionModuleName};
-        result = dest.addType(std::move(clone));
-    }
-    else if (FFlag::LuauClonePublicInterfaceLess && alwaysClone)
-    {
-        result = dest.addType(*ty);
-    }
-    else if (const NegationType* ntv = get<NegationType>(ty))
-    {
-        result = dest.addType(NegationType{ntv->ty});
-    }
-    else
-        return result;
-
-    asMutable(result)->documentationSymbol = ty->documentationSymbol;
-    return result;
-}
-
-TypeId shallowClone(TypeId ty, NotNull<TypeArena> dest)
-{
-    return shallowClone(ty, *dest, TxnLog::empty());
-}
-
 } // namespace Luau

Analysis/src/ConstraintGraphBuilder.cpp

@@ -23,7 +23,7 @@ LUAU_FASTFLAG(LuauNegatedClassTypes);
 namespace Luau
 {
 
-bool doesCallError(const AstExprCall* call); // TypeInfer.cpp
+bool doesCallError(const AstExprCall* call);        // TypeInfer.cpp
 const AstStat* getFallthrough(const AstStat* node); // TypeInfer.cpp
 
 static std::optional<AstExpr*> matchRequire(const AstExprCall& call)
@@ -1359,10 +1359,34 @@ InferencePack ConstraintGraphBuilder::checkPack(const ScopePtr& scope, AstExprCa
         if (argTail && args.size() < 2)
             argTailPack = extendTypePack(*arena, builtinTypes, *argTail, 2 - args.size());
 
-        LUAU_ASSERT(args.size() + argTailPack.head.size() == 2);
+        TypeId target = nullptr;
+        TypeId mt = nullptr;
 
-        TypeId target = args.size() > 0 ? args[0] : argTailPack.head[0];
-        TypeId mt = args.size() > 1 ? args[1] : argTailPack.head[args.size() == 0 ? 1 : 0];
+        if (args.size() + argTailPack.head.size() == 2)
+        {
+            target = args.size() > 0 ? args[0] : argTailPack.head[0];
+            mt = args.size() > 1 ? args[1] : argTailPack.head[args.size() == 0 ? 1 : 0];
+        }
+        else
+        {
+            std::vector<TypeId> unpackedTypes;
+            if (args.size() > 0)
+                target = args[0];
+            else
+            {
+                target = arena->addType(BlockedType{});
+                unpackedTypes.emplace_back(target);
+            }
+
+            mt = arena->addType(BlockedType{});
+            unpackedTypes.emplace_back(mt);
+            TypePackId mtPack = arena->addTypePack(std::move(unpackedTypes));
+
+            addConstraint(scope, call->location, UnpackConstraint{mtPack, *argTail});
+        }
+
+        LUAU_ASSERT(target);
+        LUAU_ASSERT(mt);
 
         AstExpr* targetExpr = call->args.data[0];
 
@@ -2090,6 +2114,19 @@ ConstraintGraphBuilder::FunctionSignature ConstraintGraphBuilder::checkFunctionS
     TypePack expectedArgPack;
 
     const FunctionType* expectedFunction = expectedType ? get<FunctionType>(*expectedType) : nullptr;
+    // This check ensures that expectedType is precisely optional and not any (since any is also an optional type)
+    if (expectedType && isOptional(*expectedType) && !get<AnyType>(*expectedType))
+    {
+        auto ut = get<UnionType>(*expectedType);
+        for (auto u : ut)
+        {
+            if (get<FunctionType>(u) && !isNil(u))
+            {
+                expectedFunction = get<FunctionType>(u);
+                break;
+            }
+        }
+    }
 
     if (expectedFunction)
     {