[cxx-interop] Clean up diagnostics for functions returning FRTs

- Delete baseline language feature WarnUnannotatedReturnOfCxxFrt,
  which won't really be useful to users
- Remove some references to "cxx", since FRTs are not exclusively
  imported from C++
- Clean up lit test RUN lines to use %{fs-sep}

Author: j-hui

include/swift/AST/DiagnosticGroups.def

@@ -45,7 +45,7 @@ GROUP(AlwaysAvailableDomain, "always-available-domain")
 GROUP(AvailabilityUnrecognizedName, "availability-unrecognized-name")
 GROUP(ClangDeclarationImport, "clang-declaration-import")
 GROUP(ConformanceIsolation, "conformance-isolation")
-GROUP(CxxForeignReferenceType, "cxx-foreign-reference-type")
+GROUP(ForeignReferenceType, "foreign-reference-type")
 GROUP(DeprecatedDeclaration, "deprecated-declaration")
 GROUP(DynamicCallable, "dynamic-callable-requirements")
 GROUP(EmbeddedRestrictions, "embedded-restrictions")

include/swift/AST/DiagnosticsSema.def

@@ -2211,7 +2211,7 @@ ERROR(expose_nested_type_to_cxx,none,
       "nested %kind0 can not yet be represented in C++", (ValueDecl *))
 ERROR(expose_macro_to_cxx,none,
       "Swift macro can not yet be represented in C++", (ValueDecl *))
-GROUPED_WARNING(warn_unannotated_cxx_func_returning_frt, CxxForeignReferenceType, none,
+GROUPED_WARNING(warn_unannotated_cxx_func_returning_frt, ForeignReferenceType, none,
         "cannot infer the ownership of the returned value, annotate %0 with "
         "either SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED",
         (const ValueDecl *))

include/swift/Basic/Features.def

@@ -213,7 +213,6 @@ BASELINE_LANGUAGE_FEATURE(BuiltinUnprotectedStackAlloc, 0, "Builtin.unprotectedS
 BASELINE_LANGUAGE_FEATURE(BuiltinTaskRunInline, 0, "Builtin.taskRunInline")
 BASELINE_LANGUAGE_FEATURE(BuiltinUnprotectedAddressOf, 0, "Builtin.unprotectedAddressOf")
 BASELINE_LANGUAGE_FEATURE(NewCxxMethodSafetyHeuristics, 0, "Only import C++ methods that return pointers (projections) on owned types as unsafe")
-BASELINE_LANGUAGE_FEATURE(WarnUnannotatedReturnOfCxxFrt, 0, "Warn about unannotated C++ functions returning foreign reference types")
 BASELINE_LANGUAGE_FEATURE(SpecializeAttributeWithAvailability, 0, "@_specialize attribute with availability")
 BASELINE_LANGUAGE_FEATURE(BuiltinAssumeAlignment, 0, "Builtin.assumeAlignment")
 BASELINE_LANGUAGE_FEATURE(BuiltinCreateTaskGroupWithFlags, 0, "Builtin.createTaskGroupWithFlags")

test/Interop/Cxx/foreign-reference/frt-reference-returns-diagnostics.swift

@@ -1,5 +1,6 @@
-// RUN: rm -rf %t
-// RUN: %target-typecheck-verify-swift -I %S%{fs-sep}Inputs -cxx-interoperability-mode=default -verify-additional-file %S%{fs-sep}Inputs%{fs-sep}frt-reference-returns.h
+// RUN: %target-typecheck-verify-swift -cxx-interoperability-mode=default \
+// RUN:   -I %S%{fs-sep}Inputs \
+// RUN:   -verify-additional-file %S%{fs-sep}Inputs%{fs-sep}frt-reference-returns.h
 
 import FRTReferenceReturns
 

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

@@ -1,9 +1,7 @@
-// RUN: rm -rf %t
-// 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 
-
+// RUN: %target-swift-frontend -typecheck -verify -cxx-interoperability-mode=default \
+// RUN:   -Xcc -Wno-return-type -Xcc -Wno-nullability-completeness \
+// RUN:   -I %S%{fs-sep}Inputs %s \
+// RUN:   -verify-additional-file %S%{fs-sep}Inputs%{fs-sep}cxx-functions-and-methods-returning-frt.h
 
 import FunctionsAndMethodsReturningFRT
 import CxxStdlib

test/Interop/Cxx/foreign-reference/inheritance-diagnostics.swift

@@ -1,6 +1,7 @@
-// RUN: rm -rf %t
-// RUN: %target-swift-frontend -typecheck -verify -I %S%{fs-sep}Inputs  %s -cxx-interoperability-mode=upcoming-swift -verify-additional-file %S%{fs-sep}Inputs%{fs-sep}inheritance.h -Xcc -Wno-return-type -Xcc -Wno-inaccessible-base
-
+// RUN: %target-swift-frontend -typecheck -verify -cxx-interoperability-mode=default \
+// RUN:   -Xcc -Wno-return-type -Xcc -Wno-inaccessible-base \
+// RUN:   -I %S%{fs-sep}Inputs %s \
+// RUN:   -verify-additional-file %S%{fs-sep}Inputs%{fs-sep}inheritance.h
 
 import Inheritance
 

test/Interop/Cxx/objc-correctness/objc-returning-cxx-frt-diagnostics.swift

@@ -1,10 +1,12 @@
-// RUN: rm -rf %t
-// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs  %s -cxx-interoperability-mode=upcoming-swift -verify-additional-file %S/Inputs/cxx-frt.h -Xcc -Wno-return-type
+// RUN: %target-swift-frontend -typecheck -verify -cxx-interoperability-mode=default \
+// RUN:   -Xcc -Wno-return-type \
+// RUN:   -I %S/Inputs %s \
+// RUN:   -verify-additional-file %S/Inputs/cxx-frt.h
 
+// REQUIRES: objc_interop
 
 import CxxForeignRef
 
-// REQUIRES: objc_interop
 func testObjCMethods() {
     _ = Bridge.objCMethodReturningFRTBothAnnotations()
     _ = Bridge.objCMethodReturningNonCxxFrtAnannotated()