c++ loosing const?

[Philipp Thomas]

This code
----------------------------------------------
template<class T>
class Link_array
{
public:
  Link_array () {}
  Link_array (Link_array<T> const &src) {}
  // quicksort.
  void sort (int (*compare) (T *const&,T *const&),
	     int lower = -1, int upper = -1);
};

class Note_column
{
public:
  static int shift_compare (int *const &, int *const &) {};
};

class Collision			// interface
{
public:
  int automatic_shift ();
};

template<class T> void
Link_array<T>::sort (int (*compare) (T *const&,T *const&),
		int lower, int upper) 
{
  int last = lower;
  sort (compare, lower, last-1);
}

int
Collision::automatic_shift ()
{
  int d = 1;
  Link_array<int> clashes;

  clashes.sort (Note_column::shift_compare);
  return 1;
}

int main()
{
  return 0;
}
----------------------------------------------
Results in:

gcc31_bug_const.cc: In member function `int Collision::automatic_shift()':
gcc31_bug_const.cc:38: invalid conversion from `int (*)(int* const&, int* const&)' to `int (*)(int*&, int*&)'
gcc31_bug_const.cc:38:   initializing argument 1 of `void Link_array<T>::sort(int (*)(T*&, T*&), int, int) [with T = int]'
gcc31_bug_const.cc: In member function `void Link_array<T>::sort(int (*)(T*&, T*&), int, int) [with T = int]':
gcc31_bug_const.cc:38:   instantiated from here
gcc31_bug_const.cc:29: invalid conversion from `int (*)(int* const&, int* const&)' to `int (*)(int*&, int*&)'
gcc31_bug_const.cc:29:   initializing argument 1 of `void Link_array<T>::sort(int (*)(T*&, T*&), int, int) [with T = int]'

As far as I understand C++ (which isn't necessarily much), this is a bug in
gcc and not in the code. But before entering a possibly invalid PR, I'd like
to confirm that this is indeed a bug in gcc.

Philipp

-- 
Philipp Thomas <pthomas@suse.de>
SuSE Linux AG, Deutscherrnstr. 15-19, D-90429 Nuremberg, Germany