Respect @preconcurrency on nominal types uniformly

When determining whether a non-sendable type is a nominal type that is
affected by `@preconcurrency`, be sure to look at the specific type
even when it's part of larger type, e.g., the `NS` in `NS?`. This
makes `@preconcurrency` work properly through structural types like
arrays, optionals, and dictionaries.

While here, also check whether the nominal declaration itself has been
marked as `@preconcurrency`.

Fixes rdar://125081249.

Author: DougGregor

lib/Sema/TypeCheckConcurrency.cpp

@@ -840,16 +840,25 @@ SendableCheckContext::preconcurrencyBehavior(Decl *decl) const {
     return std::nullopt;
 
   if (auto *nominal = dyn_cast<NominalTypeDecl>(decl)) {
-    // Determine whether this nominal type is visible via a @preconcurrency
-    // import.
-    auto import = nominal->findImport(fromDC);
-    auto sourceFile = fromDC->getParentSourceFile();
+    ModuleDecl *importedModule = nullptr;
+    if (nominal->getAttrs().hasAttribute<PreconcurrencyAttr>()) {
+      // If the declaration itself has the @preconcurrency attribute,
+      // respect it.
+      importedModule = nominal->getParentModule();
+    } else {
+      // Determine whether this nominal type is visible via a @preconcurrency
+      // import.
+      auto import = nominal->findImport(fromDC);
+      auto sourceFile = fromDC->getParentSourceFile();
 
-    if (!import || !import->options.contains(ImportFlags::Preconcurrency))
-      return std::nullopt;
+      if (!import || !import->options.contains(ImportFlags::Preconcurrency))
+        return std::nullopt;
 
-    if (sourceFile)
-      sourceFile->setImportUsedPreconcurrency(*import);
+      if (sourceFile)
+        sourceFile->setImportUsedPreconcurrency(*import);
+
+      importedModule = import->module.importedModule;
+    }
 
     // When the type is explicitly non-Sendable, @preconcurrency imports
     // downgrade the diagnostic to a warning in Swift 6.
@@ -858,7 +867,7 @@ SendableCheckContext::preconcurrencyBehavior(Decl *decl) const {
 
     // When the type is implicitly non-Sendable, `@preconcurrency` suppresses
     // diagnostics until the imported module enables Swift 6.
-    return import->module.importedModule->isConcurrencyChecked()
+    return importedModule->isConcurrencyChecked()
         ? DiagnosticBehavior::Warning
         : DiagnosticBehavior::Ignore;
   }
@@ -5708,7 +5717,7 @@ static bool checkSendableInstanceStorage(
           /*inDerivedConformance*/Type(), element->getLoc(),
           [&](Type type, DiagnosticBehavior behavior) {
             auto preconcurrency =
-                context.preconcurrencyBehavior(elementType->getAnyNominal());
+                context.preconcurrencyBehavior(type->getAnyNominal());
             if (isImplicitSendableCheck(check)) {
               // If this is for an externally-visible conformance, fail.
               if (check == SendableCheck::ImplicitForExternallyVisible) {
@@ -5719,7 +5728,7 @@ static bool checkSendableInstanceStorage(
               // If we are to ignore this diagnostic, just continue.
               if (behavior == DiagnosticBehavior::Ignore ||
                   preconcurrency == DiagnosticBehavior::Ignore)
-                return false;
+                return true;
 
               invalid = true;
               return true;

lib/Sema/TypeCheckConcurrency.h

@@ -441,7 +441,7 @@ bool diagnoseNonSendableTypes(
       type, fromContext, derivedConformance, typeLoc,
       [&](Type specificType, DiagnosticBehavior behavior) {
         auto preconcurrency =
-            fromContext.preconcurrencyBehavior(type->getAnyNominal());
+          fromContext.preconcurrencyBehavior(specificType->getAnyNominal());
 
         ctx.Diags.diagnose(diagnoseLoc, diag, type, diagArgs...)
             .limitBehaviorUntilSwiftVersion(behavior, 6)
@@ -477,7 +477,7 @@ bool diagnoseIfAnyNonSendableTypes(
       type, fromContext, derivedConformance, typeLoc,
       [&](Type specificType, DiagnosticBehavior behavior) {
         auto preconcurrency =
-            fromContext.preconcurrencyBehavior(type->getAnyNominal());
+          fromContext.preconcurrencyBehavior(specificType->getAnyNominal());
 
         if (behavior == DiagnosticBehavior::Ignore ||
             preconcurrency == DiagnosticBehavior::Ignore)

test/Concurrency/predates_concurrency_import.swift

@@ -16,17 +16,29 @@
 @preconcurrency import OtherActors
 // expected-warning@-1{{'@preconcurrency' attribute on module 'OtherActors' has no effect}}{{1-17=}}
 
+@preconcurrency
+class MyPredatesConcurrencyClass { }
+
+enum EnumWithPredatesConcurrencyValue {
+  case stored(MyPredatesConcurrencyClass)
+}
+
 func acceptSendable<T: Sendable>(_: T) { }
 
 @available(SwiftStdlib 5.1, *)
 func test(
   ss: StrictStruct, ns: NonStrictClass, oma: OtherModuleActor,
-  ssc: SomeSendableClass
+  ssOpt: StrictStruct?, nsOpt: NonStrictClass?
+  ssc: SomeSendableClass,
+  mpcc: MyPredatesConcurrencyClass
 ) async {
   acceptSendable(ss) // expected-warning{{type 'StrictStruct' does not conform to the 'Sendable' protocol}}
   acceptSendable(ns) // silence issue entirely
+  acceptSendable(ssOpt) // expected-warning{{type 'StrictStruct?' does not conform to the 'Sendable' protocol}}
+  acceptSendable(nsOpt) // silence issue entirely
   acceptSendable(oma) // okay
   acceptSendable(ssc) // okay
+  acceptSendable(mpcc)
 }
 
 let nonStrictGlobal = NonStrictClass() // no warning

test/Concurrency/transfernonsendable_preconcurrency.swift

@@ -6,9 +6,6 @@
 // A swift 5 module /with/ concurrency checking
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/PreconcurrencyChecked.swiftmodule -module-name PreconcurrencyChecked %S/Inputs/transfernonsendable_preconcurrency_checked.swift -disable-availability-checking -swift-version 5 -strict-concurrency=complete
 
-// Test swift 5 with strict concurrency with region isolation disabled
-// RUN: %target-swift-frontend -swift-version 5 %s -emit-sil -o /dev/null -verify -verify-additional-prefix swift-5-no-tns- -parse-as-library -I %t -strict-concurrency=complete -disable-availability-checking -disable-region-based-isolation-with-strict-concurrency
-
 // Test swift 5 with strict concurrency
 // RUN: %target-swift-frontend -swift-version 5 %s -emit-sil -o /dev/null -verify -verify-additional-prefix swift-5- -parse-as-library -I %t -strict-concurrency=complete -disable-availability-checking
 
@@ -26,7 +23,7 @@
 ////////////////////////
 
 @preconcurrency import PreconcurrencyUnchecked
-import PreconcurrencyChecked // expected-swift-5-no-tns-warning {{add '@preconcurrency' to suppress 'Sendable'-related warnings from module 'PreconcurrencyChecked'}}
+import PreconcurrencyChecked
 
 typealias PreCUncheckedNonSendableKlass = PreconcurrencyUnchecked.NonSendableKlass
 typealias PreCUncheckedExplicitlyNonSendableKlass = PreconcurrencyUnchecked.ExplicitlyNonSendableKlass
@@ -62,11 +59,10 @@ func testPreconcurrencyImplicitlyNonSendable() async {
 func testPreconcurrencyExplicitlyNonSendable() async {
   let x = PreCUncheckedExplicitlyNonSendableKlass()
   await transferToMain(x)
-  // expected-swift-5-no-tns-warning @-1 {{passing argument of non-sendable type 'PreCUncheckedExplicitlyNonSendableKlass' (aka 'ExplicitlyNonSendableKlass') into main actor-isolated context may introduce data races}}
-  // expected-swift-5-warning @-2 {{sending 'x' risks causing data races}}
-  // expected-swift-5-note @-3 {{sending 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-swift-6-warning @-4 {{sending 'x' risks causing data races}}
-  // expected-swift-6-note @-5 {{sending 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-swift-5-warning @-1 {{sending 'x' risks causing data races}}
+  // expected-swift-5-note @-2 {{sending 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-swift-6-warning @-3 {{sending 'x' risks causing data races}}
+  // expected-swift-6-note @-4 {{sending 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
   useValue(x)
   // expected-swift-5-note @-1 {{access can happen concurrently}}
   // expected-swift-6-note @-2 {{access can happen concurrently}}
@@ -75,7 +71,7 @@ func testPreconcurrencyExplicitlyNonSendable() async {
 // In swift 5 this is a warning and in swift 6 this is an error.
 func testNormal() async {
   let x = PostCUncheckedNonSendableKlass()
-  await transferToMain(x) // expected-swift-5-no-tns-warning {{passing argument of non-sendable type 'PostCUncheckedNonSendableKlass' (aka 'NonSendableKlass') into main actor-isolated context may introduce data races}}
+  await transferToMain(x)
   // expected-swift-5-warning @-1 {{sending 'x' risks causing data races}}
   // expected-swift-6-error @-2 {{sending 'x' risks causing data races}}
   // expected-swift-5-note @-3 {{sending 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
@@ -90,11 +86,10 @@ func testOnlyErrorOnExactValue() async {
   // We would squelch this if we transferred it directly. Also we error even
   // though we use x later.
   await transferToMain(y)
-  // expected-swift-5-no-tns-warning @-1 2{{passing argument of non-sendable type '(PreCUncheckedNonSendableKlass, PreCUncheckedNonSendableKlass)' (aka '(NonSendableKlass, NonSendableKlass)') into main actor-isolated context may introduce data races}}
-  // expected-swift-5-warning @-2 {{sending 'y' risks causing data races}}
-  // expected-swift-5-note @-3 {{sending 'y' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
-  // expected-swift-6-error @-4 {{sending 'y' risks causing data races}}
-  // expected-swift-6-note @-5 {{sending 'y' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-swift-5-warning @-1 {{sending 'y' risks causing data races}}
+  // expected-swift-5-note @-2 {{sending 'y' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
+  // expected-swift-6-error @-3 {{sending 'y' risks causing data races}}
+  // expected-swift-6-note @-4 {{sending 'y' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and local nonisolated uses}}
   useValue(x)
   // expected-swift-5-note @-1 {{access can happen concurrently}}
   // expected-swift-6-note @-2 {{access can happen concurrently}}
@@ -117,15 +112,15 @@ func testNeverTransfer(_ x: PreCUncheckedNonSendableKlass) async {
 }
 
 func testNeverTransferExplicit(_ x: PreCUncheckedExplicitlyNonSendableKlass) async {
-  await transferToMain(x) // expected-swift-5-no-tns-warning {{passing argument of non-sendable type 'PreCUncheckedExplicitlyNonSendableKlass' (aka 'ExplicitlyNonSendableKlass') into main actor-isolated context may introduce data races}}
+  await transferToMain(x)
   // expected-swift-5-warning @-1 {{sending 'x' risks causing data races}}
   // expected-swift-5-note @-2 {{sending task-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and task-isolated uses}}
   // expected-swift-6-warning @-3 {{sending 'x' risks causing data races}}
   // expected-swift-6-note @-4 {{sending task-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and task-isolated uses}}
 }
 
 func testNeverTransferNormal(_ x: PostCUncheckedNonSendableKlass) async {
-  await transferToMain(x) // expected-swift-5-no-tns-warning {{passing argument of non-sendable type 'PostCUncheckedNonSendableKlass' (aka 'NonSendableKlass') into main actor-isolated context may introduce data races}}
+  await transferToMain(x)
   // expected-swift-5-warning @-1 {{sending 'x' risks causing data races}}
   // expected-swift-5-note @-2 {{sending task-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and task-isolated uses}}
   // expected-swift-6-error @-3 {{sending 'x' risks causing data races}}
@@ -134,7 +129,7 @@ func testNeverTransferNormal(_ x: PostCUncheckedNonSendableKlass) async {
 
 // Inexact match => normal behavior.
 func testNeverTransferInexactMatch(_ x: (PreCUncheckedNonSendableKlass, PreCUncheckedNonSendableKlass)) async {
-  await transferToMain(x) // expected-swift-5-no-tns-warning 2{{passing argument of non-sendable type '(PreCUncheckedNonSendableKlass, PreCUncheckedNonSendableKlass)' (aka '(NonSendableKlass, NonSendableKlass)') into main actor-isolated context may introduce data races}}
+  await transferToMain(x)
   // expected-swift-5-warning @-1 {{sending 'x' risks causing data races}}
   // expected-swift-5-note @-2 {{sending task-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and task-isolated uses}}
   // expected-swift-6-error @-3 {{sending 'x' risks causing data races}}
@@ -143,7 +138,7 @@ func testNeverTransferInexactMatch(_ x: (PreCUncheckedNonSendableKlass, PreCUnch
 
 // Inexact match => normal behavior.
 func testNeverTransferInexactMatchExplicit(_ x: (PreCUncheckedExplicitlyNonSendableKlass, PreCUncheckedExplicitlyNonSendableKlass)) async {
-  await transferToMain(x) // expected-swift-5-no-tns-warning {{passing argument of non-sendable type '(PreCUncheckedExplicitlyNonSendableKlass, PreCUncheckedExplicitlyNonSendableKlass)' (aka '(ExplicitlyNonSendableKlass, ExplicitlyNonSendableKlass)') into main actor-isolated context may introduce data races}}
+  await transferToMain(x)
   // expected-swift-5-warning @-1 {{sending 'x' risks causing data races}}
   // expected-swift-5-note @-2 {{sending task-isolated 'x' to main actor-isolated global function 'transferToMain' risks causing data races between main actor-isolated and task-isolated uses}}
   // expected-swift-6-error @-3 {{sending 'x' risks causing data races}}