In Parser::isCXXDeclarationSpecifier, consider a non-type identifier

followed by an identifier as declaration specificer (except for ObjC).
This allows e.g. an out-of-line C++ member function definitions to be
recognized as functions and not as variable declarations if the type
name for the first parameter is not recognized as a type--say, when there
is a function name shadowing an enum type name and the parameter is
missing the "enum" keyword needed to distinguish the two.

Note that returning TPResult::Error() instead of TPResult::True()
appears to have the same end result, while TPResult::Ambiguous()
results in a crash.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@155163 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Parse/ParseTentative.cpp

@@ -931,8 +931,12 @@ Parser::isCXXDeclarationSpecifier(Parser::TPResult BracedCastResult) {
     // recurse to handle whatever we get.
     if (TryAnnotateTypeOrScopeToken())
       return TPResult::Error();
-    if (Tok.is(tok::identifier))
-      return TPResult::False();
+    if (Tok.is(tok::identifier)) {
+      const Token &Next = NextToken();
+      bool NotObjC = !(getLangOpts().ObjC1 || getLangOpts().ObjC2);
+      return (NotObjC && Next.is(tok::identifier)) ?
+          TPResult::True() : TPResult::False();
+    }
     return isCXXDeclarationSpecifier(BracedCastResult);
 
   case tok::coloncolon: {    // ::foo::bar

test/FixIt/fixit.cpp

@@ -204,3 +204,15 @@ template<template<typename> Foo, // expected-error {{template template parameter
          template<typename> typename Bar, // expected-error {{template template parameter requires 'class' after the parameter list}}
          template<typename> struct Baz> // expected-error {{template template parameter requires 'class' after the parameter list}}
 void func();
+
+
+namespace ShadowedTagType {
+class Foo {
+ public:
+  enum Bar { X, Y };
+  void SetBar(Bar bar);
+  Bar Bar();
+ private:
+  Bar bar_; // expected-error {{must use 'enum' tag to refer to type 'Bar' in this scope}}
+};
+void Foo::SetBar(Bar bar) { bar_ = bar; } // expected-error {{must use 'enum' tag to refer to type 'Bar' in this scope}}