[cxx-interop] Relax error when using SWIFT_RETURNS_(UN)RETAINED on templated return types resolving to non-frts (#78968)

We should not complain about usage of SWIFT_RETURNS_(UN)RETAINED for templated C++ APIs when instantiated with a non SWIFT_SHARED_REFERENCE types

rdar://143732201

Author: fahadnayyar

lib/ClangImporter/ImportDecl.cpp

@@ -3656,6 +3656,11 @@ namespace {
         }
       } else {
         if (returnsRetainedAttrIsPresent || returnsUnretainedAttrIsPresent) {
+          if (const auto *functionDecl = dyn_cast<clang::FunctionDecl>(decl)) {
+            if (functionDecl->isTemplateInstantiation()) {
+              return;
+            }
+          }
           Impl.diagnose(
               loc,
               diag::

test/Interop/Cxx/foreign-reference/Inputs/cxx-functions-and-methods-returning-frt.h

@@ -4,9 +4,9 @@
 // FRT or SWIFT_SHARED_REFERENCE type
 struct FRTStruct {
   // Friend function declarations
-  friend FRTStruct *returnInstanceOfFRTStruct(int v);
-  friend FRTStruct *returnInstanceOfFRTStructWithAttrReturnsRetained(int v);
-  friend FRTStruct *returnInstanceOfFRTStructWithAttrReturnsUnretained(int v);
+  friend FRTStruct *returnInstanceOfFRTStruct(int v); // expected-warning {{'returnInstanceOfFRTStruct' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE}}
+  friend FRTStruct *returnInstanceOfFRTStructWithAttrReturnsRetained(int v); // expected-warning {{'returnInstanceOfFRTStructWithAttrReturnsRetained' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE}}
+  friend FRTStruct *returnInstanceOfFRTStructWithAttrReturnsUnretained(int v); // expected-warning {{'returnInstanceOfFRTStructWithAttrReturnsUnretained' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE}}
 } __attribute__((swift_attr("import_reference")))
 __attribute__((swift_attr("retain:retainFRTStruct")))
 __attribute__((swift_attr("release:releaseFRTStruct")));
@@ -146,15 +146,15 @@ struct StructWithStaticMethodsReturningFRTWithAttributeReturnsUnretained {
 // Global/free C++ functions returning FRT with both attributes
 // swift_attr("returns_unretained") and swift_attr("returns_retained")
 FRTStruct
-    *_Nonnull global_function_returning_FRT_with_both_attrs_returns_retained_returns_unretained()
+    *_Nonnull global_function_returning_FRT_with_both_attrs_returns_retained_returns_unretained() // expected-error {{'global_function_returning_FRT_with_both_attrs_returns_retained_returns_unretained' cannot be annotated with both SWIFT_RETURNS_RETAINED and SWIFT_RETURNS_UNRETAINED}}
         __attribute__((swift_attr("returns_retained")))
         __attribute__((swift_attr("returns_unretained")));
 
 // Struct having static method returning FRT with both attributes
 // swift_attr("returns_unretained") and swift_attr("returns_retained")
 struct
     StructWithStaticMethodsReturningFRTWithBothAttributesReturnsRetainedAndReturnsUnretained {
-  static FRTStruct *_Nonnull StaticMethodReturningFRT()
+  static FRTStruct *_Nonnull StaticMethodReturningFRT() // expected-error {{'StaticMethodReturningFRT' cannot be annotated with both SWIFT_RETURNS_RETAINED and SWIFT_RETURNS_UNRETAINED}}
       __attribute__((swift_attr("returns_retained")))
       __attribute__((swift_attr("returns_unretained")));
 };
@@ -178,50 +178,50 @@ __attribute__((swift_attr("unsafe")));
 
 // C++ APIs returning cxx frts (for testing diagnostics)
 struct StructWithAPIsReturningCxxFrt {
-  static FRTStruct *_Nonnull StaticMethodReturningCxxFrt();
+  static FRTStruct *_Nonnull StaticMethodReturningCxxFrt(); // expected-warning {{'StaticMethodReturningCxxFrt' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE}} 
   static FRTStruct *_Nonnull StaticMethodReturningCxxFrtWithAnnotation()
       __attribute__((swift_attr("returns_retained")));
 };
 
-FRTStruct *_Nonnull global_function_returning_cxx_frt();
+FRTStruct *_Nonnull global_function_returning_cxx_frt(); // expected-warning {{'global_function_returning_cxx_frt' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE}}
 FRTStruct *_Nonnull global_function_returning_cxx_frt_with_annotations()
     __attribute__((swift_attr("returns_retained")));
 
 // C++ APIs returning non-cxx-frts (for testing diagnostics)
 struct StructWithAPIsReturningNonCxxFrt {
   static NonFRTStruct *_Nonnull StaticMethodReturningNonCxxFrt();
-  static NonFRTStruct *_Nonnull StaticMethodReturningNonCxxFrtWithAnnotation()
+  static NonFRTStruct *_Nonnull StaticMethodReturningNonCxxFrtWithAnnotation() // expected-error {{'StaticMethodReturningNonCxxFrtWithAnnotation' cannot be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type}}
       __attribute__((swift_attr("returns_retained")));
 };
 
 NonFRTStruct *_Nonnull global_function_returning_non_cxx_frt();
-NonFRTStruct *_Nonnull global_function_returning_non_cxx_frt_with_annotations()
+NonFRTStruct *_Nonnull global_function_returning_non_cxx_frt_with_annotations() // expected-error {{'global_function_returning_non_cxx_frt_with_annotations' cannot be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type}}
     __attribute__((swift_attr("returns_retained")));
 
 // C++ APIs returning SWIFT_IMMORTAL_REFERENCE types (for testing diagnostics)
 struct StructWithAPIsReturningImmortalReference {
   static ImmortalRefStruct *_Nonnull StaticMethodReturningImmortalReference();
   static ImmortalRefStruct
-      *_Nonnull StaticMethodReturningImmortalReferenceWithAnnotation()
+      *_Nonnull StaticMethodReturningImmortalReferenceWithAnnotation() // expected-error {{'StaticMethodReturningImmortalReferenceWithAnnotation' cannot be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type}}
           __attribute__((swift_attr("returns_retained")));
 };
 
 ImmortalRefStruct *_Nonnull global_function_returning_immortal_reference();
 ImmortalRefStruct
-    *_Nonnull global_function_returning_immortal_reference_with_annotations()
+    *_Nonnull global_function_returning_immortal_reference_with_annotations() // expected-error {{'global_function_returning_immortal_reference_with_annotations' cannot be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type}}
         __attribute__((swift_attr("returns_retained")));
 
 // C++ APIs returning SWIFT_UNSAFE_REFERENCE types (for testing diagnostics)
 struct StructWithAPIsReturningUnsafeReference {
   static UnsafeRefStruct *_Nonnull StaticMethodReturningUnsafeReference();
   static UnsafeRefStruct
-      *_Nonnull StaticMethodReturningUnsafeReferenceWithAnnotation()
+      *_Nonnull StaticMethodReturningUnsafeReferenceWithAnnotation() // expected-error {{'StaticMethodReturningUnsafeReferenceWithAnnotation' cannot be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type}}
           __attribute__((swift_attr("returns_retained")));
 };
 
 UnsafeRefStruct *_Nonnull global_function_returning_unsafe_reference();
 UnsafeRefStruct
-    *_Nonnull global_function_returning_unsafe_reference_with_annotations()
+    *_Nonnull global_function_returning_unsafe_reference_with_annotations() // expected-error {{'global_function_returning_unsafe_reference_with_annotations' cannot be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type}}
         __attribute__((swift_attr("returns_retained")));
 
 // Global/free C++ functions returning non-FRT
@@ -296,13 +296,13 @@ __attribute__((swift_attr(
 
 public:
   FRTOverloadedOperators *_Nonnull
-  operator+(const FRTOverloadedOperators &other)
+  operator+(const FRTOverloadedOperators &other) // expected-warning {{SWIFT_RETURNS_RETAINED and SWIFT_RETURNS_UNRETAINED is not supported yet for overloaded C++ 'operator+'. Overloaded C++ operators always return SWIFT_SHARED_REFERENCE types as owned}}
       __attribute__((swift_attr("returns_unretained")));
   FRTOverloadedOperators *_Nonnull
   operator-(const FRTOverloadedOperators &other);
 };
 
-FRTOverloadedOperators *_Nonnull returnFRTOverloadedOperators();
+FRTOverloadedOperators *_Nonnull returnFRTOverloadedOperators(); // expected-warning {{'returnFRTOverloadedOperators' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE}}
 
 void retain_FRTOverloadedOperators(FRTOverloadedOperators *_Nonnull v);
 void release_FRTOverloadedOperators(FRTOverloadedOperators *_Nonnull v);

test/Interop/Cxx/foreign-reference/frt-retained-unretained-attributes-error.swift

@@ -1,55 +1,34 @@
 // RUN: rm -rf %t
-// RUN: not %target-swift-frontend -typecheck -I %S/Inputs  %s -cxx-interoperability-mode=upcoming-swift 2>&1 | %FileCheck %s
+ // RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs  %s -cxx-interoperability-mode=upcoming-swift -verify-additional-file %S/Inputs/cxx-functions-and-methods-returning-frt.h -Xcc -Wno-return-type -Xcc -Wno-nullability-completeness
+
+// XFAIL: OS=windows-msvc
+// TODO: Enable this on windows when -verify-additional-file issue on Windows Swift CI is resolved 
 
 import FunctionsAndMethodsReturningFRT
 import CxxStdlib
 
 let frtLocalVar1 = global_function_returning_FRT_with_both_attrs_returns_retained_returns_unretained()
-// CHECK: error: 'global_function_returning_FRT_with_both_attrs_returns_retained_returns_unretained' cannot be annotated with both SWIFT_RETURNS_RETAINED and SWIFT_RETURNS_UNRETAINED
-
 let frtLocalVar2 = StructWithStaticMethodsReturningFRTWithBothAttributesReturnsRetainedAndReturnsUnretained.StaticMethodReturningFRT()
-// CHECK: error: 'StaticMethodReturningFRT' cannot be annotated with both SWIFT_RETURNS_RETAINED and SWIFT_RETURNS_UNRETAINED
 let frtLocalVar3 = StructWithAPIsReturningCxxFrt.StaticMethodReturningCxxFrt()
-// CHECK: warning: 'StaticMethodReturningCxxFrt' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE
 let frtLocalVar4 = StructWithAPIsReturningCxxFrt.StaticMethodReturningCxxFrtWithAnnotation()
-
 let frtLocalVar5 = global_function_returning_cxx_frt()
-// CHECK: warning: 'global_function_returning_cxx_frt' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE
 let frtLocalVar6 = global_function_returning_cxx_frt_with_annotations()
-
 let frtLocalVar7 = StructWithAPIsReturningNonCxxFrt.StaticMethodReturningNonCxxFrt()
 let frtLocalVar8 = StructWithAPIsReturningNonCxxFrt.StaticMethodReturningNonCxxFrtWithAnnotation()
-// CHECK: error: 'StaticMethodReturningNonCxxFrtWithAnnotation' cannot be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type
-
 let frtLocalVar9 = global_function_returning_non_cxx_frt()
 let frtLocalVar10 = global_function_returning_non_cxx_frt_with_annotations()
-// CHECK: error: 'global_function_returning_non_cxx_frt_with_annotations' cannot be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type
-
 let frtLocalVar11 = StructWithAPIsReturningImmortalReference.StaticMethodReturningImmortalReference()
 let frtLocalVar12 = StructWithAPIsReturningImmortalReference.StaticMethodReturningImmortalReferenceWithAnnotation()
-// CHECK: error: 'StaticMethodReturningImmortalReferenceWithAnnotation' cannot be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type
-
 let frtLocalVar13 = global_function_returning_immortal_reference()
 let frtLocalVar14 = global_function_returning_immortal_reference_with_annotations()
-// CHECK: error: 'global_function_returning_immortal_reference_with_annotations' cannot be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type
-
-let frtLocalVar15 = StructWithAPIsReturningUnsafeReference.StaticMethodReturningUnsafeReference()
 let frtLocalVar16 = StructWithAPIsReturningUnsafeReference.StaticMethodReturningUnsafeReferenceWithAnnotation()
-// CHECK: error: 'StaticMethodReturningUnsafeReferenceWithAnnotation' cannot be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type
-
 let frtLocalVar17 = global_function_returning_unsafe_reference()
 let frtLocalVar18 = global_function_returning_unsafe_reference_with_annotations()
-// CHECK: error: 'global_function_returning_unsafe_reference_with_annotations' cannot be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED because it is not returning a SWIFT_SHARED_REFERENCE type
-
 let x = returnFRTOverloadedOperators()
-// CHECK: warning: 'returnFRTOverloadedOperators' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE
 let y = returnFRTOverloadedOperators()
-// CHECK: warning: 'returnFRTOverloadedOperators' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE
 let z = x + y
-// CHECK: warning: SWIFT_RETURNS_RETAINED and SWIFT_RETURNS_UNRETAINED is not supported yet for overloaded C++ 'operator+'. Overloaded C++ operators always return SWIFT_SHARED_REFERENCE types as owned
 let w = x - y
-// CHECK-NOT: warning: 'operator-' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE
-
 let f = FunctionVoidToFRTStruct()
 let frt = f()
-// CHECK-NOT: warning: 'operator()' should be annotated with either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED as it is returning a SWIFT_SHARED_REFERENCE
+let nonFrt = NonFRTStruct()
+let nonFrtLocalVar1 = global_function_returning_templated_retrun_frt_owned(nonFrt)

test/Interop/Cxx/foreign-reference/frt-retained-unretained-attributes.swift

@@ -185,7 +185,7 @@ func testStaticMethodsReturningNonFRT() {
     // CHECK: function_ref @{{.*}}StaticMethodReturningNonFRT_copy{{.*}} : $@convention(c) () -> UnsafeMutablePointer<NonFRTStruct> 
 }
 
-func testtFreeFunctionsTemplated(frt : FRTStruct) {
+func testtFreeFunctionsTemplated(frt : FRTStruct, nonFrt: NonFRTStruct) {
     let frtLocalVar1 : Int = 1;
 
     let frtLocalVar2 = global_templated_function_returning_FRT(frtLocalVar1)
@@ -227,6 +227,8 @@ func testtFreeFunctionsTemplated(frt : FRTStruct) {
     let frtLocalVar14 = global_function_returning_templated_retrun_frt_owned(frt)
     // CHECK: function_ref @{{.*}}global_function_returning_templated_retrun_frt_owned{{.*}} : $@convention(c) (FRTStruct) -> @owned FRTStruct
 
+    let nonFrtLocalVar1 = global_function_returning_templated_retrun_frt_owned(nonFrt)
+    // CHECK: function_ref @{{.*}}global_function_returning_templated_retrun_frt_owned{{.*}} : $@convention(c) (NonFRTStruct) -> NonFRTStruct
 }
 
 func testVirtualMethods(base: Base, derived: Derived) {