Sync to upstream/release/702 (#2126)

Hello!

This week, we've made a bunch of improvements to the performance and
stability of the analysis system. We've also made some small
improvements to inlining and native codegen.

# Autocomplete

* Suggest singleton string keys from indexers

# General

* Reduce stack utilization of the parser

# Analysis

* User-defined type functions don't need separate irreducible errors
when they error.
* Fix a performance problem that could occur when selecting an overload
for a function call.
* Fix a hang that could occur in function generalization.
* Delete EqSat. It was a very promising experiment but it didn't work
out.
* Properly treat negation types as being contravariant in their
operands. (ie if `A <: B`, then `~B <: ~A`)
* Add a new C++ utility function `Frontend::parseType`. This function
allocates a `TypeId` from a string that contains a valid Luau type
annotation.
* Correctly infer the type of a property lookup on a table which
contains an indexer which is a union of string singletons. (eg
`{["foo"|"bar"]: number}`)

# VM

* Reevaluate the inlining cost model using constant function arguments.
* Constant-fold `string.char` and `string.sub`.

# Native Codegen
* Fix a perfermance regression that could happen when running out of
registers.
* 32-bit integer addition and subtraction using bit32 library can be
performed by integer instructions without extra double conversions
 
# Internal Contributors

Co-authored-by: Andy Friesen <[email protected]>
Co-authored-by: Ariel Weiss <[email protected]>
Co-authored-by: Hunter Goldstein <[email protected]>
Co-authored-by: Sora Kanosue <[email protected]>
Co-authored-by: Vyacheslav Egorov <[email protected]>

---------

Co-authored-by: Hunter Goldstein <[email protected]>
Co-authored-by: Varun Saini <[email protected]>
Co-authored-by: Alexander Youngblood <[email protected]>
Co-authored-by: Menarul Alam <[email protected]>
Co-authored-by: Aviral Goel <[email protected]>
Co-authored-by: Vighnesh <[email protected]>
Co-authored-by: Vyacheslav Egorov <[email protected]>
Co-authored-by: Ariel Weiss <[email protected]>
Co-authored-by: Ilya Rezvov <[email protected]>

Author: 10 people

Analysis/include/Luau/ConstraintGenerator.h

@@ -6,7 +6,6 @@
 #include "Luau/ConstraintSet.h"
 #include "Luau/ControlFlow.h"
 #include "Luau/DataFlowGraph.h"
-#include "Luau/EqSatSimplification.h"
 #include "Luau/HashUtil.h"
 #include "Luau/InsertionOrderedMap.h"
 #include "Luau/Module.h"
@@ -113,8 +112,6 @@ struct ConstraintGenerator
     // Needed to be able to enable error-suppression preservation for immediate refinements.
     NotNull<Normalizer> normalizer;
 
-    NotNull<Simplifier> simplifier;
-
     // Needed to register all available type functions for execution at later stages.
     NotNull<TypeFunctionRuntime> typeFunctionRuntime;
     DenseHashMap<const AstStatTypeFunction*, ScopePtr> astTypeFunctionEnvironmentScopes{nullptr};
@@ -141,7 +138,6 @@ struct ConstraintGenerator
     ConstraintGenerator(
         ModulePtr module,
         NotNull<Normalizer> normalizer,
-        NotNull<Simplifier> simplifier,
         NotNull<TypeFunctionRuntime> typeFunctionRuntime,
         NotNull<ModuleResolver> moduleResolver,
         NotNull<BuiltinTypes> builtinTypes,
@@ -381,6 +377,7 @@ struct ConstraintGenerator
     TypeId resolveTableType(const ScopePtr& scope, AstType* ty, AstTypeTable* tab, bool inTypeArguments, bool replaceErrorWithFresh);
     TypeId resolveFunctionType(const ScopePtr& scope, AstType* ty, AstTypeFunction* fn, bool inTypeArguments, bool replaceErrorWithFresh);
 
+public:
     /**
      * Resolves a type from its AST annotation.
      * @param scope the scope that the type annotation appears within.
@@ -390,6 +387,7 @@ struct ConstraintGenerator
      **/
     TypeId resolveType(const ScopePtr& scope, AstType* ty, bool inTypeArguments, bool replaceErrorWithFresh = false);
 
+private:
     // resolveType() is recursive, but we only want to invoke
     // inferGenericPolarities() once at the very end.  We thus isolate the
     // recursive part of the algorithm to this internal helper.

Analysis/include/Luau/ConstraintSolver.h

@@ -6,7 +6,6 @@
 #include "Luau/ConstraintSet.h"
 #include "Luau/DataFlowGraph.h"
 #include "Luau/DenseHash.h"
-#include "Luau/EqSatSimplification.h"
 #include "Luau/Error.h"
 #include "Luau/Location.h"
 #include "Luau/Module.h"
@@ -101,7 +100,6 @@ struct ConstraintSolver
     NotNull<BuiltinTypes> builtinTypes;
     InternalErrorReporter iceReporter;
     NotNull<Normalizer> normalizer;
-    NotNull<Simplifier> simplifier;
     NotNull<TypeFunctionRuntime> typeFunctionRuntime;
     // The entire set of constraints that the solver is trying to resolve.
     ConstraintSet constraintSet;
@@ -167,7 +165,6 @@ struct ConstraintSolver
 
     explicit ConstraintSolver(
         NotNull<Normalizer> normalizer,
-        NotNull<Simplifier> simplifier,
         NotNull<TypeFunctionRuntime> typeFunctionRuntime,
         ModulePtr module,
         NotNull<ModuleResolver> moduleResolver,
@@ -181,7 +178,6 @@ struct ConstraintSolver
     // TODO CLI-169086: Replace all uses of this constructor with the ConstraintSet constructor, above.
     explicit ConstraintSolver(
         NotNull<Normalizer> normalizer,
-        NotNull<Simplifier> simplifier,
         NotNull<TypeFunctionRuntime> typeFunctionRuntime,
         NotNull<Scope> rootScope,
         std::vector<NotNull<Constraint>> constraints,

Analysis/include/Luau/DataFlowGraph.h

@@ -112,6 +112,8 @@ struct DataFlowGraphBuilder
         NotNull<struct InternalErrorReporter> handle
     );
 
+    static DataFlowGraph empty(NotNull<DefArena> defArena, NotNull<RefinementKeyArena> keyArena);
+
 private:
     DataFlowGraphBuilder(NotNull<DefArena> defArena, NotNull<RefinementKeyArena> keyArena);