[Distributed] Allow isolated any DistributedActor

include/swift/AST/Types.h

@@ -922,6 +922,9 @@ class alignas(1 << TypeAlignInBits) TypeBase
   /// Determines whether this type is an actor type.
   bool isActorType();
 
+  /// Determines whether this type is an any actor type.
+  bool isAnyActorType();
+
   /// Returns true if this type is a Sendable type.
   bool isSendableType(DeclContext *declContext);
 

lib/AST/Type.cpp

@@ -574,6 +574,12 @@ bool TypeBase::isActorType() {
   return false;
 }
 
+bool TypeBase::isAnyActorType() {
+  if (auto actor = getAnyActor())
+    return actor->isAnyActor();
+  return false;
+}
+
 bool TypeBase::isSendableType(DeclContext *ctx) {
   return isSendableType(ctx->getParentModule());
 }

lib/Sema/TypeCheckType.cpp

@@ -4484,12 +4484,12 @@ TypeResolver::resolveIsolatedTypeRepr(IsolatedTypeRepr *repr,
   Type type = resolveType(repr->getBase(), options);
 
   // isolated parameters must be of actor type
-  if (!type->hasTypeParameter() && !type->isActorType() && !type->hasError()) {
+  if (!type->hasTypeParameter() && !type->isAnyActorType() && !type->hasError()) {
     // Optional actor types are fine - `nil` represents `nonisolated`.
     auto wrapped = type->getOptionalObjectType();
     auto allowOptional = getASTContext().LangOpts
         .hasFeature(Feature::OptionalIsolatedParameters);
-    if (allowOptional && wrapped && wrapped->isActorType()) {
+    if (allowOptional && wrapped && wrapped->isAnyActorType()) {
       return type;
     }
 

test/Distributed/Runtime/distributed_actor_isolated_existential.swift

@@ -0,0 +1,64 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend-emit-module -emit-module-path %t/FakeDistributedActorSystems.swiftmodule -module-name FakeDistributedActorSystems -disable-availability-checking %S/../Inputs/FakeDistributedActorSystems.swift
+// RUN: %target-build-swift -module-name main -j2 -parse-as-library -I %t %s %S/../Inputs/FakeDistributedActorSystems.swift -o %t/a.out
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out
+
+// REQUIRES: executable_test
+// REQUIRES: concurrency
+// REQUIRES: distributed
+
+// rdar://76038845
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: back_deployment_runtime
+// UNSUPPORTED: freestanding
+
+// FIXME(distributed): Distributed actors currently have some issues on windows rdar://82593574
+// UNSUPPORTED: OS=windows-msvc
+
+import StdlibUnittest
+import Distributed
+import FakeDistributedActorSystems
+
+@available(SwiftStdlib 5.9, *)
+typealias DefaultDistributedActorSystem = FakeRoundtripActorSystem
+
+@available(SwiftStdlib 5.9, *)
+func globalFunc(isolatedTo actor: isolated any DistributedActor) async {
+  MainActor.preconditionIsolated() // we forced the `actor` onto the main actor's executor
+}
+
+@available(SwiftStdlib 5.9, *) // because conforming to the protocol requirement introduced in 5.9
+distributed actor NormalWorker {
+
+  nonisolated var unownedExecutor: UnownedSerialExecutor {
+    return MainActor.sharedUnownedExecutor
+  }
+
+  distributed func offerSelf() async {
+    print("executed: \(#function)")
+    MainActor.preconditionIsolated() // we forced the `actor` onto the main actor's executor
+
+    await globalFunc(isolatedTo: self)
+    MainActor.preconditionIsolated() // we forced the `actor` onto the main actor's executor
+  }
+}
+
+@available(SwiftStdlib 5.1, *)
+@main struct Main {
+  @available(SwiftStdlib 5.1, *)
+  static func main() async {
+    if #available(SwiftStdlib 5.9, *) {
+      let tests = TestSuite("DistributedIsolatedTests")
+      let system = DefaultDistributedActorSystem()
+      let normalLocalWorker = NormalWorker(actorSystem: system)
+      precondition(__isLocalActor(normalLocalWorker), "must be local")
+
+      tests.test("remote actor reference should have crash-on-enqueue executor") {
+        try! await normalLocalWorker.offerSelf()
+      }
+
+      await runAllTestsAsync()
+    }
+  }
+}

test/Distributed/distributed_actor_isolation.swift

@@ -260,3 +260,5 @@ extension Greeting where SerializationRequirement == Codable {
 }
 
 func isolated_generic_ok<T: DistributedActor>(_ t: isolated T) {}
+
+func isolated_existential_ok(_ t: isolated any DistributedActor) {}