diff --git a/test/ClangImporter/objc_async_conformance.swift b/test/ClangImporter/objc_async_conformance.swift
index ff20f1b8971bb..e463a4b6cacea 100644
--- a/test/ClangImporter/objc_async_conformance.swift
+++ b/test/ClangImporter/objc_async_conformance.swift
@@ -116,3 +116,33 @@ 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) -> ()'}}
+}
+
+class ImplementsFloatLoader: FloatLoader {
+  public func loadFloat(completionHandler: @escaping (Float) -> Void) {}
+}
+
+class ImplementsFloatLoader2: FloatLoader {
+  public func loadFloat(withCompletionHandler completionHandler: @escaping (Float) -> Void) {}
+  // expected-warning@-1 {{instance method 'loadFloat(withCompletionHandler:)' nearly matches optional requirement 'loadFloat(completionHandler:)' of protocol 'FloatLoader'}}
+  // expected-note@-2 {{rename to 'loadFloat(completionHandler:)' to satisfy this requirement}}
+  // expected-note@-3 {{move 'loadFloat(withCompletionHandler:)' to an extension to silence this warning}}
+}
diff --git a/test/Inputs/clang-importer-sdk/usr/include/ObjCConcurrency.h b/test/Inputs/clang-importer-sdk/usr/include/ObjCConcurrency.h
index 1029b9072b655..0a85dbe69fcef 100644
--- a/test/Inputs/clang-importer-sdk/usr/include/ObjCConcurrency.h
+++ b/test/Inputs/clang-importer-sdk/usr/include/ObjCConcurrency.h
@@ -355,4 +355,13 @@ MAIN_ACTOR
 - (void)loadStuffWithGroupID:(NSInteger)groupID reply:(void (^)())reply;
 @end
 
+@protocol DictionaryLoader
+- (void)loadDictionaryWithCompletionHandler:(void (^)(NSDictionary <NSString *, NSNumber *> * _Nullable))completionHandler;
+@end
+
+@protocol FloatLoader
+@optional
+- (void)loadFloatWithCompletionHandler:(void (^)(float))completionHandler;
+@end
+
 #pragma clang assume_nonnull end