Fixed no copying IsIsolated flag when cloning subscript params

include/swift/AST/Decl.h

@@ -6993,6 +6993,10 @@ class ParamDecl : public VarDecl {
   /// Create a an identical copy of this ParamDecl.
   static ParamDecl *clone(const ASTContext &Ctx, ParamDecl *PD);
 
+  static ParamDecl *cloneAccessor(const ASTContext &Ctx,
+                                  ParamDecl const *subscriptParam,
+                                  DeclContext *Parent);
+
   static ParamDecl *
   createImplicit(ASTContext &Context, SourceLoc specifierLoc,
                  SourceLoc argumentNameLoc, Identifier argumentName,

lib/AST/Decl.cpp

@@ -8888,6 +8888,21 @@ ParamDecl *ParamDecl::clone(const ASTContext &Ctx, ParamDecl *PD) {
   return Clone;
 }
 
+ParamDecl *ParamDecl::cloneAccessor(const ASTContext &Ctx,
+                                    ParamDecl const *subscriptParam,
+                                    DeclContext *Parent) {
+  auto *param = new (Ctx) ParamDecl(
+      subscriptParam->getSpecifierLoc(), subscriptParam->getArgumentNameLoc(),
+      subscriptParam->getArgumentName(), subscriptParam->getNameLoc(),
+      subscriptParam->getName(), /*declContext*/ Parent);
+  param->setOptions(subscriptParam->getOptions());
+
+  // The cloned parameter is implicit.
+  param->setImplicit();
+
+  return param;
+}
+
 ParamDecl *
 ParamDecl::createImplicit(ASTContext &Context, SourceLoc specifierLoc,
                           SourceLoc argumentNameLoc, Identifier argumentName,
@@ -11107,23 +11122,7 @@ AccessorDecl *AccessorDecl::createParsed(
       paramsEnd = indices->getEndLoc();
     }
     for (auto *subscriptParam : *indices) {
-      // Clone the parameter.
-      auto *param = new (ctx) ParamDecl(
-          subscriptParam->getSpecifierLoc(),
-          subscriptParam->getArgumentNameLoc(),
-          subscriptParam->getArgumentName(), subscriptParam->getNameLoc(),
-          subscriptParam->getName(), /*declContext*/ accessor);
-      param->setAutoClosure(subscriptParam->isAutoClosure());
-
-      // The cloned parameter is implicit.
-      param->setImplicit();
-
-      if (subscriptParam->isSending())
-        param->setSending();
-
-      if (subscriptParam->isCallerIsolated())
-        param->setCallerIsolated();
-
+      auto param = ParamDecl::cloneAccessor(ctx, subscriptParam, accessor);
       newParams.push_back(param);
     }
 

test/Concurrency/isolated_parameters.swift

@@ -8,7 +8,7 @@
 
 @available(SwiftStdlib 5.1, *)
 actor A {
-  func f() { } // expected-typechecker-note 5{{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
+  func f() { } // expected-typechecker-note 3{{calls to instance method 'f()' from outside of its actor context are implicitly asynchronous}}
 }
 
 @available(SwiftStdlib 5.1, *)
@@ -364,11 +364,8 @@ func isolatedClosures() {
   // expected-typechecker-warning@+2 {{cannot have more than one 'isolated' parameter; this is an error in the Swift 6 language mode}}
   // expected-typechecker-warning@+1 {{subscript with 'isolated' parameter cannot be 'nonisolated'; this is an error in the Swift 6 language mode}}{{3-15=}}
   nonisolated subscript(_ a: isolated A, _ b: isolated A) -> Int {
-    // FIXME: wrong isolation. should be isolated to `a`.
-    #if ALLOW_TYPECHECKER_ERRORS
-    a.f() // expected-typechecker-error {{call to actor-isolated instance method 'f()' in a synchronous actor-isolated context}}
-    b.f() // expected-typechecker-error {{call to actor-isolated instance method 'f()' in a synchronous actor-isolated context}}
-    #endif
+    a.f()
+    b.f()
     return 0
   }
 
@@ -591,3 +588,14 @@ public actor MyActorIsolatedParameterMerge {
 class ClassWithIsolatedAsyncInitializer {
     init(isolation: isolated (any Actor)? = #isolation) async {}
 }
+
+// https://github.com/swiftlang/swift/issues/80992
+struct WritableActorKeyPath<Root: Actor, Value>: Sendable {
+    var getter: @Sendable (isolated Root) -> Value
+    var setter: @Sendable (isolated Root, Value) -> Void
+
+    subscript(_ root: isolated Root) -> Value {
+        get { getter(root) }
+        nonmutating set { setter(root, newValue) }
+    }
+}