Sync to upstream/release/668 (#1760)

## New Type Solver

1. Update resolved types for singleton unions and intersections to avoid
crashing when type checking type assertions.
2. Generalize free return type pack of a function type inferred at call
site to ensure that the free type does not leak to another module.
3. Fix crash from cyclic indexers by reducing if possible or producing
an error otherwise.
4. Fix handling of irreducible type functions to prevent type inference
from failing.
5. Fix handling of recursive metatables to avoid infinite recursion.

## New and Old Type Solver

Fix accidental capture of all exceptions in multi-threaded typechecking
by converting all typechecking exceptions to `InternalCompilerError` and
only capturing those.

## Fragment Autocomplete

1. Add a block based diff algorithm based on class index and span for
re-typechecking. This reduces the granularity of fragment autocomplete
to avoid flakiness when the fragment does not have enough type
information.
2. Fix bugs arising from incorrect scope selection for autocompletion.

## Roundtrippable AST

Store type alias location in `TypeFun` class to ensure it is accessible
for exported types as part of the public interface.

## Build System

1. Bump minimum supported CMake version to 3.10 since GitHub is phasing
out the currently supported minimum version 3.0, released 11 years ago.
2. Fix compilation when `HARDSTACKTESTS` is enabled.

## Miscellaneous

Flag removals and cleanup of unused code.

## Internal Contributors

Co-authored-by: Andy Friesen <afriesen@roblox.com>
Co-authored-by: Ariel Weiss <aaronweiss@roblox.com>
Co-authored-by: Hunter Goldstein <hgoldstein@roblox.com>
Co-authored-by: Talha Pathan <tpathan@roblox.com>
Co-authored-by: Vighnesh Vijay <vvijay@roblox.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>

## External Contributors

Thanks to [@grh-official](https://github.com/grh-official) for PR #1759 

**Full Changelog**:
0.667...0.668

---------

Co-authored-by: Hunter Goldstein <hgoldstein@roblox.com>
Co-authored-by: Varun Saini <61795485+vrn-sn@users.noreply.github.com>
Co-authored-by: Alexander Youngblood <ayoungblood@roblox.com>
Co-authored-by: Menarul Alam <malam@roblox.com>
Co-authored-by: Vighnesh <vvijay@roblox.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
Co-authored-by: Ariel Weiss <aaronweiss@roblox.com>

Author: 8 people

Analysis/include/Luau/ConstraintGenerator.h

@@ -132,6 +132,8 @@ struct ConstraintGenerator
 
     DenseHashMap<TypeId, TypeIds> localTypes{nullptr};
 
+    DenseHashMap<AstExpr*, Inference> inferredExprCache{nullptr};
+
     DcrLogger* logger;
 
     ConstraintGenerator(

Analysis/include/Luau/FragmentAutocomplete.h

@@ -86,6 +86,7 @@ struct FragmentRegion
     AstStatBlock* parentBlock = nullptr; // used for scope detection
 };
 
+std::optional<Position> blockDiffStart(AstStatBlock* blockOld, AstStatBlock* blockNew, AstStat* nearestStatementNewAst);
 FragmentRegion getFragmentRegion(AstStatBlock* root, const Position& cursorPosition);
 FragmentAutocompleteAncestryResult findAncestryForFragmentParse(AstStatBlock* stale, const Position& cursorPos, AstStatBlock* lastGoodParse);
 FragmentAutocompleteAncestryResult findAncestryForFragmentParse_DEPRECATED(AstStatBlock* root, const Position& cursorPos);

Analysis/include/Luau/Frontend.h

@@ -215,11 +215,6 @@ struct Frontend
         std::function<void(std::function<void()> task)> executeTask = {},
         std::function<bool(size_t done, size_t total)> progress = {}
     );
-    std::vector<ModuleName> checkQueuedModules_DEPRECATED(
-        std::optional<FrontendOptions> optionOverride = {},
-        std::function<void(std::function<void()> task)> executeTask = {},
-        std::function<bool(size_t done, size_t total)> progress = {}
-    );
 
     std::optional<CheckResult> getCheckResult(const ModuleName& name, bool accumulateNested, bool forAutocomplete = false);
     std::vector<ModuleName> getRequiredScripts(const ModuleName& name);

Analysis/include/Luau/Module.h

@@ -15,8 +15,6 @@
 #include <unordered_map>
 #include <optional>
 
-LUAU_FASTFLAG(LuauIncrementalAutocompleteCommentDetection)
-
 namespace Luau
 {
 

Analysis/include/Luau/TxnLog.h

@@ -192,16 +192,6 @@ struct TxnLog
     // The pointer returned lives until `commit` or `clear` is called.
     PendingTypePack* changeLevel(TypePackId tp, TypeLevel newLevel);
 
-    // Queues the replacement of a type's scope with the provided scope.
-    //
-    // The pointer returned lives until `commit` or `clear` is called.
-    PendingType* changeScope(TypeId ty, NotNull<Scope> scope);
-
-    // Queues the replacement of a type pack's scope with the provided scope.
-    //
-    // The pointer returned lives until `commit` or `clear` is called.
-    PendingTypePack* changeScope(TypePackId tp, NotNull<Scope> scope);
-
     // Queues a replacement of a table type with another table type with a new
     // indexer.
     //

Analysis/include/Luau/Type.h

@@ -356,10 +356,8 @@ struct FunctionType
     );
 
     // Local monomorphic function
-    FunctionType(TypeLevel level, TypePackId argTypes, TypePackId retTypes, std::optional<FunctionDefinition> defn = {}, bool hasSelf = false);
     FunctionType(
         TypeLevel level,
-        Scope* scope,
         TypePackId argTypes,
         TypePackId retTypes,
         std::optional<FunctionDefinition> defn = {},
@@ -376,16 +374,6 @@ struct FunctionType
         std::optional<FunctionDefinition> defn = {},
         bool hasSelf = false
     );
-    FunctionType(
-        TypeLevel level,
-        Scope* scope,
-        std::vector<TypeId> generics,
-        std::vector<TypePackId> genericPacks,
-        TypePackId argTypes,
-        TypePackId retTypes,
-        std::optional<FunctionDefinition> defn = {},
-        bool hasSelf = false
-    );
 
     std::optional<FunctionDefinition> definition;
     /// These should all be generic
@@ -394,7 +382,6 @@ struct FunctionType
     std::vector<std::optional<FunctionArgument>> argNames;
     Tags tags;
     TypeLevel level;
-    Scope* scope = nullptr;
     TypePackId argTypes;
     TypePackId retTypes;
     std::shared_ptr<MagicFunction> magic = nullptr;
@@ -481,7 +468,9 @@ struct Property
     TypeId type() const;
     void setType(TypeId ty);
 
-    // Sets the write type of this property to the read type.
+    // If this property has a present `writeTy`, set it equal to the `readTy`.
+    // This is to ensure that if we normalize a property that has divergent
+    // read and write types, we make them converge (for now).
     void makeShared();
 
     bool isShared() const;
@@ -526,9 +515,6 @@ struct TableType
     std::optional<TypeId> boundTo;
     Tags tags;
 
-    // Methods of this table that have an untyped self will use the same shared self type.
-    std::optional<TypeId> selfTy;
-
     // We track the number of as-yet-unadded properties to unsealed tables.
     // Some constraints will use this information to decide whether or not they
     // are able to dispatch.
@@ -890,23 +876,33 @@ struct TypeFun
      */
     TypeId type;
 
+    // The location of where this TypeFun was defined, if available
+    std::optional<Location> definitionLocation;
+
     TypeFun() = default;
 
     explicit TypeFun(TypeId ty)
         : type(ty)
     {
     }
 
-    TypeFun(std::vector<GenericTypeDefinition> typeParams, TypeId type)
+    TypeFun(std::vector<GenericTypeDefinition> typeParams, TypeId type, std::optional<Location> definitionLocation = std::nullopt)
         : typeParams(std::move(typeParams))
         , type(type)
+        , definitionLocation(definitionLocation)
     {
     }
 
-    TypeFun(std::vector<GenericTypeDefinition> typeParams, std::vector<GenericTypePackDefinition> typePackParams, TypeId type)
+    TypeFun(
+        std::vector<GenericTypeDefinition> typeParams,
+        std::vector<GenericTypePackDefinition> typePackParams,
+        TypeId type,
+        std::optional<Location> definitionLocation = std::nullopt
+    )
         : typeParams(std::move(typeParams))
         , typePackParams(std::move(typePackParams))
         , type(type)
+        , definitionLocation(definitionLocation)
     {
     }
 

Analysis/src/BuiltinDefinitions.cpp

@@ -29,7 +29,6 @@
  */
 
 LUAU_FASTFLAG(LuauSolverV2)
-LUAU_FASTFLAGVARIABLE(LuauStringFormatErrorSuppression)
 LUAU_FASTFLAGVARIABLE(LuauTableCloneClonesType3)
 LUAU_FASTFLAG(LuauTrackInteriorFreeTypesOnScope)
 LUAU_FASTFLAGVARIABLE(LuauFollowTableFreeze)
@@ -712,10 +711,8 @@ bool MagicFormat::typeCheck(const MagicFunctionTypeCheckContext& context)
 
         if (!result.isSubtype)
         {
-            if (FFlag::LuauStringFormatErrorSuppression)
+            switch (shouldSuppressErrors(NotNull{&context.typechecker->normalizer}, actualTy))
             {
-                switch (shouldSuppressErrors(NotNull{&context.typechecker->normalizer}, actualTy))
-                {
                 case ErrorSuppression::Suppress:
                     break;
                 case ErrorSuppression::NormalizationFailed:
@@ -725,12 +722,6 @@ bool MagicFormat::typeCheck(const MagicFunctionTypeCheckContext& context)
 
                     if (!reasonings.suppressed)
                         context.typechecker->reportError(TypeMismatch{expectedTy, actualTy, reasonings.toString()}, location);
-                }
-            }
-            else
-            {
-                Reasonings reasonings = context.typechecker->explainReasonings(actualTy, expectedTy, location, result);
-                context.typechecker->reportError(TypeMismatch{expectedTy, actualTy, reasonings.toString()}, location);
             }
         }
     }

Analysis/src/Clone.cpp

@@ -179,8 +179,6 @@ class TypeCloner
             generic->scope = nullptr;
         else if (auto free = getMutable<FreeType>(target))
             free->scope = nullptr;
-        else if (auto fn = getMutable<FunctionType>(target))
-            fn->scope = nullptr;
         else if (auto table = getMutable<TableType>(target))
             table->scope = nullptr;
 
@@ -521,11 +519,6 @@ class FragmentAutocompleteTypeCloner final : public TypeCloner
             if (FFlag::LuauClonedTableAndFunctionTypesMustHaveScopes)
                 tt->scope = replacementForNullScope;
         }
-        else if (auto fn = getMutable<FunctionType>(target))
-        {
-            if (FFlag::LuauClonedTableAndFunctionTypesMustHaveScopes)
-                fn->scope = replacementForNullScope;
-        }
 
         (*types)[ty] = target;
         queue.emplace_back(target);