[Bug c++/55668] New: Incorrect lookup for template member of dependent template

[tudorb at fb dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55668

             Bug #: 55668
           Summary: Incorrect lookup for template member of dependent
                    template
    Classification: Unclassified
           Product: gcc
           Version: 4.7.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: tudorb@fb.com


The following correct program gives an error; it appears that "a.template
foo<0>" looks up foo in global scope and fails because it believes that foo
takes a class first template argument instead of an int.

// The bug is not triggered if the template below is missing,
// or if it is a class or function or global variable instead of
// a template.
template <class T> class foo;

template <int N> struct A {
  template <int K> void foo(int val) { }
};

template <int N> struct B {
  // The bug is not triggered if "bar" is named "foo"
  void bar() {
    a.template foo<0>(42);
  }

  // This has to depend on N; A<0> doesn't trigger the bug
  A<N> a;
};

The error I get:

d.cpp: In member function `void B<N>::bar()`:
d.cpp:13:21: error: type/value mismatch at argument 1 in template parameter
list for `template<class T> class foo`
d.cpp:13:21: error:   expected a type, got `0`

Broken in 4.1.2, 4.6.2, 4.7.1 (the three versions I have access to).

(The bug was minimized from actual code, in which the method in question was
named "set" and collided with std::set, as we had "using std::set")