[Bug c++/52816] New: Access to private members inside decltype in the signature of a member template causes access control error

[jewillco at osl dot iu.edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52816

             Bug #: 52816
           Summary: Access to private members inside decltype in the
                    signature of a member template causes access control
                    error
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: jewil...@osl.iu.edu


When using decltype inside the return type of a member function template, I
receive access control errors for references to private member variables.  Here
is a simple example of a failing program:

class c {
  int f;
  public:
  template <typename A>
  decltype(f) m(A) const;
};

decltype(c{}.m(0)) i;

The use of old- vs. new-style function declarations does not change the
behavior; neither does whether the class itself is a template.  The error I get
from GCC 4.7.0 is:

test.cpp:2:7: error: ‘int c::f’ is private
test.cpp:8:20: error: within this context

I think that is likely to be incorrect since the reference to f is from inside
the body of the class definition itself.