[CSClosure] Allocate temporary type-join and opaque value exprs in solver arena

(cherry picked from commit f3df7ab)

Author: xedin

include/swift/AST/Expr.h

@@ -4360,6 +4360,10 @@ class OpaqueValueExpr : public Expr {
     Bits.OpaqueValueExpr.IsPlaceholder = isPlaceholder;
   }
 
+  static OpaqueValueExpr *
+  createImplicit(ASTContext &ctx, Type Ty, bool isPlaceholder = false,
+                 AllocationArena arena = AllocationArena::Permanent);
+
   /// Whether this opaque value expression represents a placeholder that
   /// is injected before type checking to act as a placeholder for some
   /// value to be specified later.
@@ -6022,17 +6026,20 @@ class TypeJoinExpr final : public Expr,
   static TypeJoinExpr *
   createImpl(ASTContext &ctx,
              llvm::PointerUnion<DeclRefExpr *, TypeBase *> varOrType,
-             ArrayRef<Expr *> elements);
+             ArrayRef<Expr *> elements,
+             AllocationArena arena = AllocationArena::Permanent);
 
 public:
-  static TypeJoinExpr *create(ASTContext &ctx, DeclRefExpr *var,
-                              ArrayRef<Expr *> exprs) {
-    return createImpl(ctx, var, exprs);
+  static TypeJoinExpr *
+  create(ASTContext &ctx, DeclRefExpr *var, ArrayRef<Expr *> exprs,
+         AllocationArena arena = AllocationArena::Permanent) {
+    return createImpl(ctx, var, exprs, arena);
   }
 
-  static TypeJoinExpr *create(ASTContext &ctx, Type joinType,
-                              ArrayRef<Expr *> exprs) {
-    return createImpl(ctx, joinType.getPointer(), exprs);
+  static TypeJoinExpr *
+  create(ASTContext &ctx, Type joinType, ArrayRef<Expr *> exprs,
+         AllocationArena arena = AllocationArena::Permanent) {
+    return createImpl(ctx, joinType.getPointer(), exprs, arena);
   }
 
   SourceLoc getLoc() const { return SourceLoc(); }

lib/AST/Expr.cpp

@@ -1559,6 +1559,15 @@ static ValueDecl *getCalledValue(Expr *E, bool skipFunctionConversions) {
   return nullptr;
 }
 
+OpaqueValueExpr *OpaqueValueExpr::createImplicit(ASTContext &ctx, Type Ty,
+                                                 bool isPlaceholder,
+                                                 AllocationArena arena) {
+  auto *mem =
+      ctx.Allocate(sizeof(OpaqueValueExpr), alignof(OpaqueValueExpr), arena);
+  return new (mem) OpaqueValueExpr(
+      /*Range=*/SourceRange(), Ty, isPlaceholder);
+}
+
 PropertyWrapperValuePlaceholderExpr *
 PropertyWrapperValuePlaceholderExpr::create(ASTContext &ctx, SourceRange range,
                                             Type ty, Expr *wrappedValue,
@@ -2540,9 +2549,9 @@ TypeJoinExpr::TypeJoinExpr(llvm::PointerUnion<DeclRefExpr *, TypeBase *> result,
 
 TypeJoinExpr *TypeJoinExpr::createImpl(
     ASTContext &ctx, llvm::PointerUnion<DeclRefExpr *, TypeBase *> varOrType,
-    ArrayRef<Expr *> elements) {
+    ArrayRef<Expr *> elements, AllocationArena arena) {
   size_t size = totalSizeToAlloc<Expr *>(elements.size());
-  void *mem = ctx.Allocate(size, alignof(TypeJoinExpr));
+  void *mem = ctx.Allocate(size, alignof(TypeJoinExpr), arena);
   return new (mem) TypeJoinExpr(varOrType, elements);
 }