[Distributed] fix AnyActorIdentity equality impl

Author: ktoso

stdlib/public/Distributed/DistributedActor.swift

@@ -138,7 +138,10 @@ public struct AnyActorIdentity: ActorIdentity, @unchecked Sendable, CustomString
         .hash(into: &hasher)
     }
     _equalTo = { other in
-      guard let rhs = other as? ID else {
+      guard let otherAnyIdentity = other as? AnyActorIdentity else {
+        return false
+      }
+      guard let rhs = otherAnyIdentity.underlying as? ID else {
         return false
       }
       return identity == rhs

test/Distributed/Runtime/distributed_actor_identity.swift

@@ -0,0 +1,59 @@
+// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking -Xfrontend -enable-experimental-distributed -parse-as-library)
+
+// REQUIRES: executable_test
+// REQUIRES: concurrency
+// REQUIRES: distributed
+
+// rdar://76038845
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: back_deployment_runtime
+
+import StdlibUnittest
+import _Distributed
+
+@available(SwiftStdlib 5.5, *)
+struct ActorAddress: ActorIdentity, CustomStringConvertible {
+  let id: String
+  var description: Swift.String {
+    "ActorAddress(id: \(id))"
+  }
+}
+
+@main struct Main {
+  static func main() async {
+    if #available(SwiftStdlib 5.5, *) {
+
+      let ActorIdentityTests = TestSuite("ActorIdentity")
+
+      ActorIdentityTests.test("equality") {
+        let a = ActorAddress(id: "a")
+        let b = ActorAddress(id: "b")
+
+        let anyA = AnyActorIdentity(a)
+        let anyB = AnyActorIdentity(b)
+
+        expectEqual(a, a)
+        expectEqual(anyA, anyA)
+
+        expectNotEqual(a, b)
+        expectNotEqual(anyA, anyB)
+      }
+
+      ActorIdentityTests.test("hash") {
+        let a = ActorAddress(id: "a")
+        let b = ActorAddress(id: "b")
+
+        let anyA = AnyActorIdentity(a)
+        let anyB = AnyActorIdentity(b)
+
+        expectEqual(a.hashValue, a.hashValue)
+        expectEqual(anyA.hashValue, anyA.hashValue)
+
+        expectNotEqual(a.hashValue, b.hashValue)
+        expectNotEqual(anyA.hashValue, anyB.hashValue)
+      }
+    }
+
+    await runAllTestsAsync()
+  }
+}