[Sema/Tests] NFC: Add a few tests to make sure that conversions that involve @execution(...) behave as expected

Author: xedin

test/Concurrency/attr_execution_conversions.swift

@@ -0,0 +1,77 @@
+// RUN: %target-typecheck-verify-swift -target %target-swift-5.1-abi-triple
+
+// REQUIRES: concurrency
+
+@execution(concurrent)
+func concurrentTest() async {
+}
+
+@execution(caller)
+func callerTest() async {
+}
+
+@MainActor
+func actorIsolated() async {}
+
+let _: @execution(caller) () async -> Void = concurrentTest // Ok
+let _: @execution(concurrent) () async -> Void = callerTest // Ok
+
+let _: @MainActor () async -> Void = concurrentTest // Ok
+let _: @MainActor () async -> Void = callerTest // Ok
+
+let _: @isolated(any) () async -> Void = concurrentTest // Ok
+let _: @isolated(any) () async -> Void = callerTest
+// expected-error@-1 {{cannot convert value of type '@execution(caller) () async -> ()' to specified type '@isolated(any) () async -> Void'}}
+
+let _: @execution(caller) () async -> Void = actorIsolated // Ok
+let _: @execution(concurrent) () async -> Void = actorIsolated // Ok
+
+func testIsolationErasure(fn: @escaping @isolated(any) () async -> Void) {
+  let _: @execution(concurrent) () async -> Void = fn // Ok
+  let _: @execution(caller) () async -> Void = fn // Ok
+}
+
+func testUpcast(arr: [@execution(caller) () async -> Void]) {
+  let _: [() async -> Void] = arr // Ok - collection upcast
+  let _: [String: () async -> Void] = ["": arr]
+  // expected-error@-1 {{cannot convert value of type '[@execution(caller) () async -> Void]' to expected dictionary value type '() async -> Void'}}
+}
+
+// Isolated parameter
+func testParameterIsolation(fn: @escaping (isolated (any Actor)?) async -> Void) {
+  let _: @execution(caller) () async -> Void = fn
+  // expected-error@-1 {{cannot convert value of type '(isolated (any Actor)?) async -> Void' to specified type '@execution(caller) () async -> Void'}}
+  let _: @execution(concurrent) () async -> Void = fn
+  // expected-error@-1 {{cannot convert value of type '(isolated (any Actor)?) async -> Void' to specified type '() async -> Void'}}
+}
+
+// Non-conversion situations
+do {
+  struct S<T> {
+  }
+  func test<T>(_: S<T>, _: T.Type) {}
+  
+  test(S<() async -> Void>(), type(of: callerTest))
+  // expected-error@-1 {{cannot convert value of type '(@execution(caller) () async -> ()).Type' to expected argument type '(() async -> Void).Type'}}
+
+  test(S<@execution(caller) () async -> Void>(), type(of: concurrentTest))
+  // expected-error@-1 {{cannot convert value of type '(() async -> ()).Type' to expected argument type '(@execution(caller) () async -> Void).Type'}}
+
+  test(S<@MainActor () async -> Void>(), type(of: callerTest))
+  // expected-error@-1 {{cannot convert value of type '(@execution(caller) () async -> ()).Type' to expected argument type '(@MainActor () async -> Void).Type'}}
+
+  test(S<@MainActor () async -> Void>(), type(of: concurrentTest))
+  // expected-error@-1 {{cannot convert value of type '(() async -> ()).Type' to expected argument type '(@MainActor () async -> Void).Type'}}
+
+  test(S<(isolated (any Actor)?) async -> Void>(), type(of: callerTest))
+  // expected-error@-1 {{cannot convert value of type '(@execution(caller) () async -> ()).Type' to expected argument type '((isolated (any Actor)?) async -> Void).Type'}}
+
+  test(S<(isolated (any Actor)?) async -> Void>(), type(of: concurrentTest))
+  // expected-error@-1 {{cannot convert value of type '(() async -> ()).Type' to expected argument type '((isolated (any Actor)?) async -> Void).Type'}}
+
+  test(S<@isolated(any) () async -> Void>(), type(of: concurrentTest))
+  // expected-error@-1 {{cannot convert value of type '(() async -> ()).Type' to expected argument type '(@isolated(any) () async -> Void).Type'}}
+  test(S<@isolated(any) () async -> Void>(), type(of: callerTest))
+  // expected-error@-1 {{cannot convert value of type '(@execution(caller) () async -> ()).Type' to expected argument type '(@isolated(any) () async -> Void).Type'}}
+}
+