[ClangImporter] Wrap compositions with Sendable protocol into existentials

Resolves: #65730

Author: xedin

lib/ClangImporter/ImportType.cpp

@@ -1916,7 +1916,13 @@ class GetSendableType :
     auto composition =
         ProtocolCompositionType::get(ctx, members, inverses, explicitAnyObject);
 
-    return { composition, true };
+    // If we started from a protocol or a composition we should already
+    // be in an existential context. Otherwise we'd have to wrap a new
+    // composition into an existential.
+    if (isa<ProtocolType>(ty) || isa<ProtocolCompositionType>(ty))
+      return {composition, true};
+
+    return {ExistentialType::get(composition), true};
   }
 
   /// Visitor action: Recurse into the children of this type and try to add

test/Concurrency/sendable_objc_attr_in_type_context_swift5.swift

@@ -58,6 +58,7 @@ void doSomethingConcurrently(__attribute__((noescape)) void SWIFT_SENDABLE (^blo
 @end
 
 @protocol InnerSendableTypes
+-(void) testComposition:(SWIFT_SENDABLE MyValue *)composition;
 -(void) test:(NSDictionary<NSString *, SWIFT_SENDABLE id> *)options;
 -(void) testWithCallback:(NSString *)name handler:(MAIN_ACTOR void (^)(NSDictionary<NSString *, SWIFT_SENDABLE id> *, NSError * _Nullable))handler;
 @end
@@ -109,6 +110,10 @@ func test_sendable_attr_in_type_context(test: Test) {
 }
 
 class TestConformanceWithStripping : InnerSendableTypes {
+  func testComposition(_: MyValue) {
+    // expected-warning@-1 {{sendability of function types in instance method 'testComposition' does not match requirement in protocol 'InnerSendableTypes'; this is an error in the Swift 6 language mode}}
+  }
+
   func test(_ options: [String: Any]) {
     // expected-warning@-1 {{sendability of function types in instance method 'test' does not match requirement in protocol 'InnerSendableTypes'; this is an error in the Swift 6 language mode}}
   }
@@ -119,6 +124,9 @@ class TestConformanceWithStripping : InnerSendableTypes {
 }
 
 class TestConformanceWithoutStripping : InnerSendableTypes {
+  func testComposition(_: any MyValue & Sendable) { // Ok
+  }
+
   func test(_ options: [String: any Sendable]) { // Ok
   }
 

test/Concurrency/sendable_objc_attr_in_type_context_swift5_strict.swift

@@ -59,6 +59,7 @@ void doSomethingConcurrently(__attribute__((noescape)) void SWIFT_SENDABLE (^blo
 @end
 
 @protocol InnerSendableTypes
+-(void) testComposition:(SWIFT_SENDABLE MyValue *)composition;
 -(void) test:(NSDictionary<NSString *, SWIFT_SENDABLE id> *)options;
 -(void) testWithCallback:(NSString *)name handler:(MAIN_ACTOR void (^)(NSDictionary<NSString *, SWIFT_SENDABLE id> *, NSError * _Nullable))handler;
 @end
@@ -116,6 +117,10 @@ func test_sendable_attr_in_type_context(test: Test) {
 class TestConformanceWithStripping : InnerSendableTypes {
   // expected-error@-1 {{type 'TestConformanceWithStripping' does not conform to protocol 'InnerSendableTypes'}}
 
+  func testComposition(_: MyValue) {
+    // expected-note@-1 {{candidate has non-matching type '(MyValue) -> ()'}}
+  }
+
   func test(_ options: [String: Any]) {
     // expected-note@-1 {{candidate has non-matching type '([String : Any]) -> ()'}}
   }
@@ -126,6 +131,9 @@ class TestConformanceWithStripping : InnerSendableTypes {
 }
 
 class TestConformanceWithoutStripping : InnerSendableTypes {
+  func testComposition(_: MyValue & Sendable) { // Ok
+  }
+
   func test(_ options: [String: any Sendable]) { // Ok
   }
 

test/Concurrency/sendable_objc_attr_in_type_context_swift6.swift

@@ -58,6 +58,7 @@ void doSomethingConcurrently(__attribute__((noescape)) void SWIFT_SENDABLE (^blo
 @end
 
 @protocol InnerSendableTypes
+-(void) testComposition:(SWIFT_SENDABLE MyValue *)composition;
 -(void) test:(NSDictionary<NSString *, SWIFT_SENDABLE id> *)options;
 -(void) testWithCallback:(NSString *)name handler:(MAIN_ACTOR void (^)(NSDictionary<NSString *, SWIFT_SENDABLE id> *, NSError * _Nullable))handler;
 @end
@@ -115,6 +116,10 @@ func test_sendable_attr_in_type_context(test: Test) {
 class TestConformanceWithStripping : InnerSendableTypes {
   // expected-error@-1 {{type 'TestConformanceWithStripping' does not conform to protocol 'InnerSendableTypes'}}
 
+  func testComposition(_: MyValue) {
+    // expected-note@-1 {{candidate has non-matching type '(MyValue) -> ()'}}
+  }
+
   func test(_ options: [String: Any]) {
     // expected-note@-1 {{candidate has non-matching type '([String : Any]) -> ()'}}
   }
@@ -125,6 +130,9 @@ class TestConformanceWithStripping : InnerSendableTypes {
 }
 
 class TestConformanceWithoutStripping : InnerSendableTypes {
+  func testComposition(_: any MyValue & Sendable) { // Ok
+  }
+
   func test(_ options: [String: any Sendable]) { // Ok
   }
 

test/IDE/print_clang_objc_async.swift

@@ -129,13 +129,12 @@ import _Concurrency
 // CHECK-LABEL: class NXSender :
 // CHECK: func sendAny(_ obj: any Sendable) -> any Sendable
 // CHECK: func sendOptionalAny(_ obj: (any Sendable)?) -> (any Sendable)?
-// FIXME(https://github.com/apple/swift/issues/65730): Compositions not wrappped in existentials
-// CHECK: func sendSendable(_ sendable: SendableClass & Sendable) -> SendableClass & Sendable
-// CHECK: func sendSendableSubclasses(_ sendableSubclass: NonSendableClass & Sendable) -> NonSendableClass & Sendable
+// CHECK: func sendSendable(_ sendable: any SendableClass & Sendable) -> any SendableClass & Sendable
+// CHECK: func sendSendableSubclasses(_ sendableSubclass: any NonSendableClass & Sendable) -> any NonSendableClass & Sendable
 // CHECK: func sendProto(_ obj: any LabellyProtocol & Sendable) -> any LabellyProtocol & Sendable
 // CHECK: func sendProtos(_ obj: any LabellyProtocol & ObjCClub & Sendable) -> any LabellyProtocol & ObjCClub & Sendable
 // CHECK: func sendAnyArray(_ array: [any Sendable]) -> [any Sendable]
-// CHECK: func sendGeneric(_ generic: GenericObject<SendableClass> & Sendable) -> GenericObject<SendableClass> & Sendable
+// CHECK: func sendGeneric(_ generic: any GenericObject<SendableClass> & Sendable) -> any GenericObject<SendableClass> & Sendable
 // CHECK: func sendPtr(_ val: UnsafeMutableRawPointer) -> UnsafeMutableRawPointer
 // CHECK: func sendStringArray(_ obj: [String]) -> [String]
 // CHECK: func sendAnyTypedef(_ obj: any Sendable) -> any Sendable