Sema: Handle declspecs without declarators in records properly in C mode

We had two bugs:
- We wouldn't properly warn when a struct/union/enum was mentioned
  inside of a record definition if no declarator was provided.  We
  should have mentioned that this declaration declares nothing.
- We didn't properly support Microsoft's extension where certain
  declspecs without declarators would act as anonymous structs/unions.
  * We completely ignored the case where such a declspec could be a
    union.
  * We didn't properly handle the case where a record was defined inside
    another record:
      struct X {
        int a;
        struct Y {
          int b;
        };
      };

llvm-svn: 215347

2 files changed, 16 insertions, 1 deletions

diff --git a/clang/test/Sema/MicrosoftExtensions.c b/clang/test/Sema/MicrosoftExtensions.c
index 429dd943a74..f64012098b2 100644
--- a/clang/test/Sema/MicrosoftExtensions.c
+++ b/clang/test/Sema/MicrosoftExtensions.c
@@ -39,9 +39,24 @@ struct nested2 {
   NESTED1;  // expected-warning {{anonymous structs are a Microsoft extension}}
 };
 
+struct nested3 {
+  long d;
+  struct nested4 { // expected-warning {{anonymous structs are a Microsoft extension}}
+    long e;
+  };
+  union nested5 { // expected-warning {{anonymous unions are a Microsoft extension}}
+    long f;
+  };
+};
+
+typedef union nested6 {
+  long f;
+} NESTED6;
+
 struct test {
   int c;
   struct nested2;   // expected-warning {{anonymous structs are a Microsoft extension}}
+  NESTED6;   // expected-warning {{anonymous unions are a Microsoft extension}}
 };
 
 void foo()
diff --git a/clang/test/Sema/anonymous-struct-union.c b/clang/test/Sema/anonymous-struct-union.c
index 35d31754162..26dbeb87f5f 100644
--- a/clang/test/Sema/anonymous-struct-union.c
+++ b/clang/test/Sema/anonymous-struct-union.c
@@ -37,7 +37,7 @@ void test_unqual_references(struct X x, const struct X xc) {
 
 struct Redecl {
   int x; // expected-note{{previous declaration is here}}
-  struct y { };
+  struct y { }; // expected-warning{{declaration does not declare anything}}
 
   union {
     int x; // expected-error{{member of anonymous union redeclares 'x'}}