[clang-format] correctly format protobuf fields named "enum".

[dchai]

Summary

Similar to TypeScript, "enum" is not a reserved word.

[MyDeveloperDay]

LGTM

[dchai]

I don't have commit access; can someone please merge this on my behalf?

cfe/trunk/lib/Format/UnwrappedLineParser.cpp

bool UnwrappedLineParser::parseEnum() {
 
   // In TypeScript, "enum" can also be used as property name, e.g. in interface
   // declarations. An "enum" keyword followed by a colon would be a syntax
   // error and thus assume it is just an identifier.
   if (Style.Language == FormatStyle::LK_JavaScript &&
       FormatTok->isOneOf(tok::colon, tok::question))
     return false;
 
+  // In protobuf, "enum" can be used as a field name.
+  if (Style.Language == FormatStyle::LK_Proto && FormatTok->is(tok::equal))
+    return false;
+
   // Eat up enum class ...
   if (FormatTok->Tok.is(tok::kw_class) || FormatTok->Tok.is(tok::kw_struct))
     nextToken();
 
   while (FormatTok->Tok.getIdentifierInfo() ||
          FormatTok->isOneOf(tok::colon, tok::coloncolon, tok::less,
                             tok::greater, tok::comma, tok::question)) {
     nextToken();

cfe/trunk/unittests/Format/FormatTestProto.cpp

TEST_F(FormatTestProto, FormatsEnums) {
   verifyFormat("enum Type {\n"
                "  UNKNOWN = 0 [(some_options) = {\n"
                "    a: aa,  // wrap\n"
                "    b: bb\n"
                "  }];\n"
                "};");
 }
 
+TEST_F(FormatTestProto, EnumAsFieldName) {
+  verifyFormat("message SomeMessage {\n"
+               "  required int32 enum = 1;\n"
+               "}");
+}
+
 TEST_F(FormatTestProto, UnderstandsReturns) {
   verifyFormat("rpc Search(SearchRequest) returns (SearchResponse);");
 }
 
 TEST_F(FormatTestProto, MessageFieldAttributes) {
   verifyFormat("optional string test = 1 [default = \"test\"];");
   verifyFormat("optional bool a = 1 [default = true, deprecated = true];");
   verifyFormat("optional LongMessageType long_proto_field = 1 [\n"