Tests: Increase test coverage in objc_async_conformance.swift.

Add regression tests for rdar://125935350.

Author: tshortli

test/ClangImporter/objc_async_conformance.swift

@@ -116,3 +116,22 @@ class C6: C5, ServiceProvider {
 extension ImplementsLoadable: @retroactive Loadable {
   public func loadStuff(withOtherIdentifier otherIdentifier: Int, reply: @escaping () -> Void) {}
 }
+
+class ImplementsDictionaryLoader1: DictionaryLoader {
+  func loadDictionary(completionHandler: @escaping ([String: NSNumber]?) -> Void) {}
+}
+
+// expected-error@+1 {{type 'ImplementsDictionaryLoader2' does not conform to protocol 'DictionaryLoader'}}
+class ImplementsDictionaryLoader2: DictionaryLoader {
+  func loadDictionary(completionHandler: @escaping ([String: Any]?) -> Void) {} // expected-note {{candidate has non-matching type '(@escaping ([String : Any]?) -> Void) -> ()'}}
+}
+
+// expected-error@+1 {{type 'ImplementsDictionaryLoader3' does not conform to protocol 'DictionaryLoader'}}
+class ImplementsDictionaryLoader3: DictionaryLoader {
+  func loadDictionary(completionHandler: @escaping ([String: NSNumber?]?) -> Void) {} // expected-note {{candidate has non-matching type '(@escaping ([String : NSNumber?]?) -> Void) -> ()'}}
+}
+
+// expected-error@+1 {{type 'ImplementsDictionaryLoader4' does not conform to protocol 'DictionaryLoader'}}
+class ImplementsDictionaryLoader4: DictionaryLoader {
+  func loadDictionary(completionHandler: @escaping ([String: Int]?) -> Void) {} // expected-note {{candidate has non-matching type '(@escaping ([String : Int]?) -> Void) -> ()'}}
+}

test/Inputs/clang-importer-sdk/usr/include/ObjCConcurrency.h

@@ -355,4 +355,8 @@ MAIN_ACTOR
 - (void)loadStuffWithGroupID:(NSInteger)groupID reply:(void (^)())reply;
 @end
 
+@protocol DictionaryLoader
+- (void)loadDictionaryWithCompletionHandler:(void (^)(NSDictionary <NSString *, NSNumber *> * _Nullable))completionHandler;
+@end
+
 #pragma clang assume_nonnull end