[Sema]Skip Sendable conformance check when are added to parameters or return types of an actor-isolated function

Author: stzn

lib/Sema/TypeCheckConcurrency.cpp

@@ -1166,6 +1166,9 @@ bool swift::diagnoseNonSendableTypesInReference(
     if (funcCheckOptions.contains(FunctionCheckKind::Params)) {
       // only check params if funcCheckKind specifies so
       for (auto param : *function->getParameters()) {
+        if (param->isSending())
+          return true;
+
         Type paramType = param->getInterfaceType().subst(subs);
         if (diagnoseNonSendableTypes(
                 paramType, fromDC, derivedConformanceType,
@@ -1179,6 +1182,9 @@ bool swift::diagnoseNonSendableTypesInReference(
     // Check the result type of a function.
     if (auto func = dyn_cast<FuncDecl>(function)) {
       if (funcCheckOptions.contains(FunctionCheckKind::Results)) {
+        if (func->hasSendingResult())
+          return true;
+
         // only check results if funcCheckKind specifies so
         Type resultType = func->getResultInterfaceType().subst(subs);
         if (diagnoseNonSendableTypes(

test/Sema/issue-76710.swift

@@ -0,0 +1,52 @@
+// RUN: %target-typecheck-verify-swift -swift-version 6
+
+// https://github.com/swiftlang/swift/issues/76710
+
+class NonSendableKlass1 {}
+
+protocol P1 {
+    func bar(_ a: sending NonSendableKlass1) async -> sending NonSendableKlass1
+}
+
+@MainActor
+class P1Class: P1 {
+  func bar(_ a: sending NonSendableKlass1) async -> sending NonSendableKlass1 { a }
+}
+
+class NonSendableKlass2 {}
+// expected-note@-1 2{{class 'NonSendableKlass2' does not conform to the 'Sendable' protocol}}
+
+protocol P2 {
+  func bar(_ a: NonSendableKlass2) async -> NonSendableKlass2
+}
+
+@MainActor
+class P2Class: P2 {
+  func bar(_ a: NonSendableKlass2) async -> NonSendableKlass2 { a }
+  // expected-error@-1 {{non-sendable type 'NonSendableKlass2' cannot be returned from main actor-isolated implementation to caller of protocol requirement 'bar'}}
+  // expected-error@-2 {{non-sendable parameter type 'NonSendableKlass2' cannot be sent from caller of protocol requirement 'bar' into main actor-isolated implementation}}
+}
+
+class NonSendableKlass3 {}
+
+protocol P3 {
+  func bar(_ a: sending NonSendableKlass3) async -> sending NonSendableKlass3
+}
+
+actor P3Actor: P3 {
+  func bar(_ a: sending NonSendableKlass3) async -> sending NonSendableKlass3 { NonSendableKlass3() }
+}
+
+class NonSendableKlass4 {}
+// expected-note@-1 2{{class 'NonSendableKlass4' does not conform to the 'Sendable' protocol}}
+
+protocol P4 {
+  func bar(_ a: NonSendableKlass4) async -> NonSendableKlass4
+}
+
+actor P4Actor: P4 {
+  func bar(_ a: NonSendableKlass4) async -> NonSendableKlass4 { NonSendableKlass4() }
+  // expected-error@-1 {{non-sendable type 'NonSendableKlass4' cannot be returned from actor-isolated implementation to caller of protocol requirement 'bar'}}
+  // expected-error@-2 {{non-sendable parameter type 'NonSendableKlass4' cannot be sent from caller of protocol requirement 'bar' into actor-isolated implementation}}
+}
+