Ensure that Sendable is inherited properly, take 3.

include/swift/AST/TypeCheckRequests.h

@@ -3095,15 +3095,15 @@ class SynthesizeMainFunctionRequest
 /// the Sendable protocol.
 class GetImplicitSendableRequest :
     public SimpleRequest<GetImplicitSendableRequest,
-                         NormalProtocolConformance *(NominalTypeDecl *),
+                         ProtocolConformance *(NominalTypeDecl *),
                          RequestFlags::Cached> {
 public:
   using SimpleRequest::SimpleRequest;
 
 private:
   friend SimpleRequest;
 
-  NormalProtocolConformance *evaluate(
+  ProtocolConformance *evaluate(
       Evaluator &evaluator, NominalTypeDecl *nominal) const;
 
 public:

include/swift/AST/TypeCheckerTypeIDZone.def

@@ -354,7 +354,7 @@ SWIFT_REQUEST(TypeChecker, SimpleDidSetRequest,
 SWIFT_REQUEST(TypeChecker, SynthesizeMainFunctionRequest,
               FuncDecl *(Decl *), Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, GetImplicitSendableRequest,
-              NormalProtocolConformance *(NominalTypeDecl *),
+              ProtocolConformance *(NominalTypeDecl *),
               Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, RenamedDeclRequest,
               ValueDecl *(const ValueDecl *),

lib/Sema/TypeCheckConcurrency.cpp

@@ -3855,7 +3855,7 @@ bool swift::checkSendableConformance(
   return checkSendableInstanceStorage(nominal, conformanceDC, check);
 }
 
-NormalProtocolConformance *GetImplicitSendableRequest::evaluate(
+ProtocolConformance *GetImplicitSendableRequest::evaluate(
     Evaluator &evaluator, NominalTypeDecl *nominal) const {
   // Protocols never get implicit Sendable conformances.
   if (isa<ProtocolDecl>(nominal))
@@ -3900,14 +3900,14 @@ NormalProtocolConformance *GetImplicitSendableRequest::evaluate(
     return nullptr;
   }
 
+  ASTContext &ctx = nominal->getASTContext();
+  auto proto = ctx.getProtocol(KnownProtocolKind::Sendable);
+  if (!proto)
+    return nullptr;
+
   // Local function to form the implicit conformance.
   auto formConformance = [&](const DeclAttribute *attrMakingUnavailable)
         -> NormalProtocolConformance * {
-    ASTContext &ctx = nominal->getASTContext();
-    auto proto = ctx.getProtocol(KnownProtocolKind::Sendable);
-    if (!proto)
-      return nullptr;
-
     DeclContext *conformanceDC = nominal;
     if (attrMakingUnavailable) {
       llvm::VersionTuple NoVersion;
@@ -3959,17 +3959,22 @@ NormalProtocolConformance *GetImplicitSendableRequest::evaluate(
 
   // A non-protocol type with a global actor is implicitly Sendable.
   if (nominal->getGlobalActorAttr()) {
-    // If this is a class, check the superclass. We won't infer Sendable
-    // if the superclass is already Sendable, to avoid introducing redundant
-    // conformances.
+    // If this is a class, check the superclass. If it's already Sendable,
+    // form an inherited conformance.
     if (classDecl) {
       if (Type superclass = classDecl->getSuperclass()) {
         auto classModule = classDecl->getParentModule();
-        if (TypeChecker::conformsToKnownProtocol(
+        if (auto inheritedConformance = TypeChecker::conformsToProtocol(
                 classDecl->mapTypeIntoContext(superclass),
-                KnownProtocolKind::Sendable,
-                classModule, /*allowMissing=*/false))
-          return nullptr;
+                proto, classModule, /*allowMissing=*/false)) {
+          inheritedConformance = inheritedConformance
+              .mapConformanceOutOfContext();
+          if (inheritedConformance.isConcrete()) {
+            return ctx.getInheritedConformance(
+                nominal->getDeclaredInterfaceType(),
+                inheritedConformance.getConcrete());
+          }
+        }
       }
     }
 

test/ClangImporter/objc_async.swift

@@ -218,4 +218,14 @@ func testMirrored(instance: ClassWithAsync) async {
   }
 }
 
+@MainActor class MyView: NXView {
+  func f() {
+    Task {
+      await self.g()
+    }
+  }
+
+  func g() async { }
+}
+
 } // SwiftStdlib 5.5