[Bug c++/50586] New: Template argument of type "pointer to function" of a template class causes usage error if template is instantiated with pointer-to-private-static-member-function

[mouchtaris at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50586

             Bug #: 50586
           Summary: Template argument of type "pointer to function" of a
                    template class causes usage error if template is
                    instantiated with
                    pointer-to-private-static-member-function
    Classification: Unclassified
           Product: gcc
           Version: 4.6.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: mouchta...@gmail.com


Created attachment 25390
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=25390
A small test file exhibiting the error.

If there is a declared template class, which accepts a pointer-to-function as a
non-type template parameter:

//////////////////////////
template <int (*f)(void)>
struct caller
  { int operator () (void) const { return (*f)(); } };
//////////////////////////

and is instantiated in a class with a pointer to a private static member
function:

//////////////////////////
class A {
  static int f (void) { return 0; }
public:
  caller<&f> get;
};
//////////////////////////

then G++ reports that "f" is private when used in the context of
caller::operator().

I haven't found anything in the standard that would impose this restriction.

(As a cue, this was reported as an error as well in older version of the vc
compiler, but in version 16.00 it is not an error any more)

I am attaching a small test file. I am not attaching any preprocessed file, as
there is no need. No preprocessor directives are used in this test.

I hope this has not been dealt before.

----------------- Detailed information -------------------

*** Compiler version: ***
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/spare/root/libexec/gcc/i686-pc-linux-gnu/4.6.1/lto-wrapper
Target: i686-pc-linux-gnu
Configured with: ../gcc-4.6.1/configure --prefix=/spare/root
Thread model: posix
gcc version 4.6.1 (GCC)


*** Compilation command: ***
g++ -ansi -pedantic -Wall -Wextra t.cpp


*** Compiler output: ***
t.cpp: In member function 'int caller<f>::operator()() const [with int (* f)()
= A::f]':
t.cpp:26:   instantiated from here
t.cpp:13: error: 'static int A::f()' is private
t.cpp:5: error: within this context