add regression test for SR-13760

Author: kavon

test/Concurrency/Inputs/Delegate.h

@@ -0,0 +1,21 @@
+#ifndef Delegate_h
+#define Delegate_h
+
+@import Foundation;
+
+@interface Request : NSObject
+
+@end
+
+@interface Delegate : NSObject
+
+- (void)makeRequest1:(Request * _Nonnull)request completionHandler:(void (^ _Nullable)(void))handler;
+
+- (void)makeRequest2:(NSObject * _Nonnull)request completionHandler:(void (^ _Nullable)(void))handler;
+
+- (void)makeRequest3:(Request * _Nullable)request completionHandler:(void (^ _Nullable)(void))handler;
+
+@end
+
+
+#endif

test/Concurrency/objc_async_overload.swift

@@ -0,0 +1,31 @@
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-experimental-concurrency -typecheck -verify -import-objc-header %S/Inputs/Delegate.h %s
+
+// REQUIRES: objc_interop
+
+
+// overload resolution should pick sync version in a sync context
+func syncContext() {
+  let r = Request()
+  let d = Delegate()
+  d.makeRequest1(r) // NOTE: this use to trigger an overload resolution error, see SR-13760
+  d.makeRequest2(r)
+  d.makeRequest3(r)
+}
+
+// overload resolution should pick async version in an async context
+func asyncNoAwait() async {
+  let r = Request()
+  let d = Delegate()
+  d.makeRequest1(r) // expected-error {{call is 'async' but is not marked with 'await'}}
+  d.makeRequest2(r) // expected-error {{call is 'async' but is not marked with 'await'}}
+  d.makeRequest3(r) // expected-error {{call is 'async' but is not marked with 'await'}}
+}
+
+
+func asyncWithAwait() async {
+  let r = Request()
+  let d = Delegate()
+  await d.makeRequest1(r)
+  await d.makeRequest2(r)
+  await d.makeRequest3(r)
+}