[Clang importer] Make sure we mirror protocol decls for all names.

When mirroring declarations from protocols, make sure to mirror for
all potential imported names. Otherwise, we might miss out on one or
the other of an async import or a completion-handler import of the
same method.

Fixes rdar://71429577.

Author: DougGregor

lib/ClangImporter/ImportDecl.cpp

@@ -7459,14 +7459,15 @@ void SwiftDeclConverter::importNonOverriddenMirroredMethods(DeclContext *dc,
 
     // Import the method.
     auto proto = entries[i].second;
-    if (auto imported =
-            Impl.importMirroredDecl(objcMethod, dc, getVersion(), proto)) {
-      members.push_back(imported);
-
-      for (auto alternate : Impl.getAlternateDecls(imported))
-        if (imported->getDeclContext() == alternate->getDeclContext())
-          members.push_back(alternate);
-    }
+    Impl.forEachDistinctName(objcMethod,
+      [&](ImportedName name, ImportNameVersion version) {
+        if (auto imported =
+              Impl.importMirroredDecl(objcMethod, dc, version, proto)) {
+          if (imported->getDeclContext() == dc)
+            members.push_back(imported);
+        }
+        return true;
+    });
   }
 }
 

test/ClangImporter/objc_async.swift

@@ -25,6 +25,8 @@ func testSlowServer(slowServer: SlowServer) async throws {
 
   await slowServer.serverRestart("localhost")
   await slowServer.server("localhost", atPriorityRestart: 0.8)
+
+  _ = await slowServer.allOperations()
 }
 
 func testSlowServerSynchronous(slowServer: SlowServer) {
@@ -36,4 +38,6 @@ func testSlowServerOldSchool(slowServer: SlowServer) {
   slowServer.doSomethingSlow("mail") { i in
     _ = i
   }
+
+  _ = slowServer.allOperations
 }

test/IDE/print_clang_objc_async.swift

@@ -6,7 +6,7 @@
 // REQUIRES: objc_interop
 // REQUIRES: concurrency
 
-// CHECK-LABEL: class SlowServer : NSObject {
+// CHECK-LABEL: class SlowServer : NSObject, ServiceProvider {
 // CHECK-DAG:     func doSomethingSlow(_ operation: String, completionHandler handler: @escaping (Int) -> Void)
 // CHECK-DAG:     func doSomethingSlow(_ operation: String) async -> Int
 // CHECK-DAG:     func doSomethingDangerous(_ operation: String, completionHandler handler: ((String?, Error?) -> Void)? = nil)

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

@@ -3,7 +3,12 @@
 
 #pragma clang assume_nonnull begin
 
-@interface SlowServer : NSObject
+@protocol ServiceProvider
+@property(readonly) NSArray<NSString *> *allOperations;
+-(void)allOperationsWithCompletionHandler:(void (^)(NSArray<NSString *> *))completion;
+@end
+
+@interface SlowServer : NSObject <ServiceProvider>
 -(void)doSomethingSlow:(NSString *)operation completionHandler:(void (^)(NSInteger))handler;
 -(void)doSomethingDangerous:(NSString *)operation completionHandler:(void (^ _Nullable)(NSString *_Nullable, NSError * _Nullable))handler;
 -(void)checkAvailabilityWithCompletionHandler:(void (^)(BOOL isAvailable))completionHandler;