Improve diagnostics when the parser encounters a declarator with an

unknown type name, e.g.,

  foo::bar x;

when "bar" does not refer to a type in "foo". 

With this change, the parser now calls into the action to perform
diagnostics and can try to recover by substituting in an appropriate
type. For example, this allows us to easily diagnose some missing
"typename" specifiers, which we now do:

  test/SemaCXX/unknown-type-name.cpp:29:1: error: missing 'typename'
        prior to dependent type name 'A<T>::type'
  A<T>::type A<T>::f() { return type(); }
  ^~~~~~~~~~
  typename 

Fixes PR3990.

llvm-svn: 84053

1 files changed, 3 insertions, 3 deletions

diff --git a/clang/test/SemaCXX/nested-name-spec.cpp b/clang/test/SemaCXX/nested-name-spec.cpp
index 4ddf3bbce4e..5178557030b 100644
--- a/clang/test/SemaCXX/nested-name-spec.cpp
+++ b/clang/test/SemaCXX/nested-name-spec.cpp
@@ -13,8 +13,8 @@ namespace A {
 }
 
 A:: ; // expected-error {{expected unqualified-id}}
-::A::ax::undef ex3; // expected-error {{no member named}} expected-error {{unknown type name 'undef'}}
-A::undef1::undef2 ex4; // expected-error {{no member named 'undef1'}} expected-error {{unknown type name 'undef2'}}
+::A::ax::undef ex3; // expected-error {{no member named}}
+A::undef1::undef2 ex4; // expected-error {{no member named 'undef1'}}
 
 int A::C::Ag1() { return 0; }
 
@@ -166,7 +166,7 @@ void N::f() { } // okay
 
 struct Y;  // expected-note{{forward declaration of 'struct Y'}}
 Y::foo y; // expected-error{{incomplete type 'struct Y' named in nested name specifier}} \
-         // expected-error{{unknown type name 'foo'}}
+         // expected-error{{no type named 'foo' in}}
 
 X::X() : a(5) { } // expected-error{{use of undeclared identifier 'X'}} \
       // expected-error{{C++ requires a type specifier for all declarations}} \