Tweak warning text for returning incomplete type from extern "C" functions.

A warning was added in r150128 for returning non-C compatible
user-defined types from functions with C linkage.

This makes the text more clear for the case when the type isn't
decidedly non-C compatible, but incomplete.

llvm-svn: 160681

1 files changed, 5 insertions, 4 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 52aa5b72d19..12444e55594 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -6086,10 +6086,11 @@ bool Sema::CheckFunctionDeclaration(Scope *S, FunctionDecl *NewFD,
     // compatible, and if it does, warn the user.
     if (NewFD->isExternC()) {
       QualType R = NewFD->getResultType();
-      if (!R.isPODType(Context) && 
-          !R->isVoidType())
-        Diag( NewFD->getLocation(), diag::warn_return_value_udt ) 
-          << NewFD << R;
+      if (R->isIncompleteType() && !R->isVoidType())
+        Diag(NewFD->getLocation(), diag::warn_return_value_udt_incomplete)
+            << NewFD << R;
+      else if (!R.isPODType(Context) && !R->isVoidType())
+        Diag(NewFD->getLocation(), diag::warn_return_value_udt) << NewFD << R;
     }
   }
   return Redeclaration;