[Bug c++/53251] New: template keyword ignored between -> and member under name collision with non-member

["potswa at mac dot com" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53251

             Bug #: 53251
           Summary: template keyword ignored between -> and member under
                    name collision with non-member
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: potswa@mac.com


Minimal testcase:

template< typename >
class set;

template< typename >
struct b {
    template<typename T>
    void set();
};

template<typename T>
struct d : b<T> {
    d() { this->template set<int>(); }
};

int main()
    { d<int> s; }

Diagnostic:

In constructor ‘d<T>::d()’:
12:17: error: invalid use of ‘class set<int>’

The name "set" is looked up in the context of the expression, outside the
class, perhaps per §3.4.5/1 [basic.lookup.classref]. Furthermore, a class found
by lookup in expression scope per 3.4.5/1 must agree with lookup in class scope
anyway (i.e. it must be a base class if class scope lookup succeeds) or the
program is ill-formed.

3.4.5/1 does not apply because the template keyword is used to mark a dependent
object expression. I suspect that somehow the hint carried by the keyword isn't
properly restricting name lookup.

For deeper discussion see http://stackoverflow.com/questions/10426428 .