Respect @preconcurrency in the diagnostic for @Sendable methods of non-Sendable types

Author: DougGregor

include/swift/AST/DiagnosticsSema.def

@@ -5520,8 +5520,8 @@ ERROR(sendable_isolated_sync_function,none,
       "%0 synchronous %kind1 cannot be marked as '@Sendable'",
       (ActorIsolation, const ValueDecl *))
 ERROR(nonsendable_instance_method,none,
-      "instance methods of non-Sendable types cannot be marked as '@Sendable'",
-      ())
+      "instance method of non-Sendable type %0 cannot be marked as '@Sendable'",
+      (Type))
 ERROR(concurrent_access_of_local_capture,none,
       "%select{mutation of|reference to}0 captured %kind1 in "
       "concurrently-executing code",

lib/Sema/TypeCheckAttr.cpp

@@ -6938,10 +6938,13 @@ void AttributeChecker::visitSendableAttr(SendableAttr *attr) {
   // Prevent Sendable Attr from being added to methods of non-sendable types
   if (auto *funcDecl = dyn_cast<AbstractFunctionDecl>(D)) {
     if (auto selfDecl = funcDecl->getImplicitSelfDecl()) {
-      if (!selfDecl->getTypeInContext()->isSendableType()) {
-        diagnose(attr->getLocation(), diag::nonsendable_instance_method)
-        .warnUntilSwiftVersion(6);
-      }
+      diagnoseIfAnyNonSendableTypes(
+          selfDecl->getTypeInContext(),
+          SendableCheckContext(funcDecl),
+          Type(),
+          SourceLoc(),
+          attr->getLocation(),
+          diag::nonsendable_instance_method);
     }
   }
 }

lib/Sema/TypeCheckConcurrency.cpp

@@ -511,7 +511,6 @@ static bool varIsSafeAcrossActors(const ModuleDecl *fromModule,
     return true;
 
   if (!var->isLet()) {
-    ASTContext &ctx = var->getASTContext();
     // A mutable storage of a value type accessed from within the module is
     // okay.
     if (dyn_cast_or_null<StructDecl>(var->getDeclContext()->getAsDecl()) &&

test/Concurrency/predates_concurrency_import.swift

@@ -33,3 +33,11 @@ let nonStrictGlobal = NonStrictClass() // no warning
 
 let strictGlobal = StrictStruct() // expected-warning{{let 'strictGlobal' is not concurrency-safe because non-'Sendable' type 'StrictStruct' may have shared mutable state}}
 // expected-note@-1{{isolate 'strictGlobal' to a global actor, or conform 'StrictStruct' to 'Sendable'}}
+
+extension NonStrictClass {
+  @Sendable func f() { }
+}
+
+extension StrictStruct {
+  @Sendable func f() { } // expected-warning{{instance method of non-Sendable type 'StrictStruct' cannot be marked as '@Sendable'}}
+}

test/Concurrency/predates_concurrency_import_swift6.swift

@@ -19,3 +19,11 @@ func test(ss: StrictStruct, ns: NonStrictClass) {
 let nonStrictGlobal = NonStrictClass()
 let strictGlobal = StrictStruct() // expected-warning{{let 'strictGlobal' is not concurrency-safe because non-'Sendable' type 'StrictStruct' may have shared mutable state}}
 // expected-note@-1{{isolate 'strictGlobal' to a global actor, or conform 'StrictStruct' to 'Sendable'}}
+
+extension NonStrictClass {
+  @Sendable func f() { }
+}
+
+extension StrictStruct {
+  @Sendable func f() { } // expected-warning{{instance method of non-Sendable type 'StrictStruct' cannot be marked as '@Sendable'}}
+}

test/Concurrency/sendable_functions.swift

@@ -1,5 +1,4 @@
-// RUN: %target-swift-frontend -emit-sil -o /dev/null -verify %s
-// RUN: %target-swift-frontend -emit-sil -o /dev/null -verify %s -strict-concurrency=targeted
+// RUN: %target-swift-frontend -emit-sil -o /dev/null -verify %s -strict-concurrency=complete
 // RUN: %target-swift-frontend -emit-sil -o /dev/null -verify %s -strict-concurrency=complete
 // RUN: %target-swift-frontend -emit-sil -o /dev/null -verify %s -strict-concurrency=complete -enable-upcoming-feature RegionBasedIsolation
 
@@ -23,18 +22,18 @@ actor A {
   }
 }
 
-class NonSendableC {
+class NonSendableC { // expected-note{{class 'NonSendableC' does not conform to the 'Sendable' protocol}}
     var x: Int = 0
 
-    @Sendable func inc() { // expected-warning{{instance methods of non-Sendable types cannot be marked as '@Sendable'}}
+    @Sendable func inc() { // expected-warning{{instance method of non-Sendable type 'NonSendableC' cannot be marked as '@Sendable'}}
         x += 1
     }
 }
 
-struct S<T> {
+struct S<T> { // expected-note{{consider making generic parameter 'T' conform to the 'Sendable' protocol}}
   let t: T
 
-  @Sendable func test() {} // expected-warning{{instance methods of non-Sendable types cannot be marked as '@Sendable'}}
+  @Sendable func test() {} // expected-warning{{instance method of non-Sendable type 'S<T>' cannot be marked as '@Sendable'}}
 }
 
 extension S: Sendable where T: Sendable {

test/Concurrency/sendable_methods.swift

@@ -1,5 +1,5 @@
-// RUN: %target-typecheck-verify-swift -enable-upcoming-feature InferSendableFromCaptures -disable-availability-checking
-// RUN: %target-swift-emit-silgen %s -verify -enable-upcoming-feature InferSendableFromCaptures -disable-availability-checking -module-name sendable_methods | %FileCheck %s
+// RUN: %target-typecheck-verify-swift -enable-upcoming-feature InferSendableFromCaptures -disable-availability-checking -strict-concurrency=complete
+// RUN: %target-swift-emit-silgen %s -verify -enable-upcoming-feature InferSendableFromCaptures -disable-availability-checking -module-name sendable_methods -strict-concurrency=complete | %FileCheck %s
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
@@ -151,10 +151,10 @@ struct World {
 
 let helloworld:  @Sendable () -> Void = World.greet
 
-class NonSendableC {
+class NonSendableC { // expected-note{{class 'NonSendableC' does not conform to the 'Sendable' protocol}}
     var x: Int = 0
 
-    @Sendable func inc() { // expected-warning {{instance methods of non-Sendable types cannot be marked as '@Sendable'; this is an error in the Swift 6 language mode}}
+    @Sendable func inc() { // expected-warning {{instance method of non-Sendable type 'NonSendableC' cannot be marked as '@Sendable'}}
         x += 1
     }
 }
@@ -186,10 +186,6 @@ struct SomeGlobalActor {
   static var shared: TestActor { TestActor() }
 }
 
-@SomeGlobalActor
-let globalValue: NonSendable = NonSendable()
-
-
 @SomeGlobalActor
 // CHECK-LABEL: sil hidden [ossa] @$s16sendable_methods8generic3yyxYalF : $@convention(thin) @async <T> (@in_guaranteed T) -> ()
 //