[-fms-extensions] Permit incomplete types in dynamic exception specifications

Microsoft headers, comdef.h and comutil.h, assume that this is an OK
thing to do.  Downgrade the hard error to a warning if we are in
-fms-extensions mode.

This fixes PR28080.

llvm-svn: 272412

1 files changed, 5 insertions, 2 deletions

diff --git a/clang/lib/Sema/SemaExceptionSpec.cpp b/clang/lib/Sema/SemaExceptionSpec.cpp
index f12bf2415db..f2ae6bfe2ff 100644
--- a/clang/lib/Sema/SemaExceptionSpec.cpp
+++ b/clang/lib/Sema/SemaExceptionSpec.cpp
@@ -110,10 +110,13 @@ bool Sema::CheckSpecifiedExceptionType(QualType &T, SourceRange Range) {
   //   A type denoted in an exception-specification shall not denote a
   //   pointer or reference to an incomplete type, other than (cv) void* or a
   //   pointer or reference to a class currently being defined.
+  // In Microsoft mode, downgrade this to a warning.
+  unsigned DiagID = diag::err_incomplete_in_exception_spec;
+  if (getLangOpts().MicrosoftExt)
+    DiagID = diag::ext_incomplete_in_exception_spec;
   if (!(PointeeT->isRecordType() &&
         PointeeT->getAs<RecordType>()->isBeingDefined()) &&
-      RequireCompleteType(Range.getBegin(), PointeeT,
-                          diag::err_incomplete_in_exception_spec, Kind, Range))
+      RequireCompleteType(Range.getBegin(), PointeeT, DiagID, Kind, Range))
     return true;
 
   return false;