[Sema] Don't allow unverified bitfields in FieldDecls

VerifyBitField must be called if we are to form a bitfield FieldDecl.
We will not verify the bitfield if the decl is known to be malformed in
other ways; pretend that we don't have a bitfield if this happens.

llvm-svn: 235816

clang/lib/Sema/SemaDecl.cpp

@@ -12481,8 +12481,10 @@ FieldDecl *Sema::CheckFieldDecl(DeclarationName Name, QualType T,
     InvalidDecl = true;
 
   bool ZeroWidth = false;
+  if (InvalidDecl)
+    BitWidth = nullptr;
   // If this is declared as a bit-field, check the bit-field.
-  if (!InvalidDecl && BitWidth) {
+  if (BitWidth) {
     BitWidth = VerifyBitField(Loc, II, T, Record->isMsStruct(Context), BitWidth,
                               &ZeroWidth).get();
     if (!BitWidth) {

clang/test/Sema/bitfield.c

@@ -74,3 +74,7 @@ typedef __typeof__(+(--t5.n)) Signed; // This should not promote to signed.
 
 typedef __typeof__(+(t5.n++)) Unsigned; // Post-increment is underspecified, but seems to
 typedef __typeof__(+(t5.n--)) Unsigned; // also act like compound-assignment.
+
+struct Test6 {
+  : 0.0; // expected-error{{type name requires a specifier or qualifier}}
+};