[Bug c++/62277] New: [C++11] constexpr member methods are treated as const, regardless of const modifier

[juchem at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62277

            Bug ID: 62277
           Summary: [C++11] constexpr member methods are treated as const,
                    regardless of const modifier
           Product: gcc
           Version: 4.9.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: juchem at gmail dot com

The following code fails to compile. Tested in Debian sid (g++ 4.8.3-9 and
4.9.1-9) and in http://ideone.com (gcc 4.8.1).

Defining CONSTEXPR to an empty macro compiles and runs successfully.

----------------------------------------------
#include <iostream>

#define CONSTEXPR constexpr

struct foo {
    CONSTEXPR char const *bar() const { return "const"; }
    CONSTEXPR char const *bar() { return "non-const"; }
};

int main() {
    foo f;
    std::cout << f.bar() << std::endl;

    foo const b;
    std::cout << b.bar() << std::endl;

    return 0;
}
----------------------------------------------

output: 
prog.cpp:7:24: error: ‘constexpr const char* foo::bar() const’ cannot be
overloaded
  CONSTEXPR char const *bar() { return "non-const"; }
                        ^
prog.cpp:6:24: error: with ‘constexpr const char* foo::bar() const’
  CONSTEXPR char const *bar() const { return "const"; }

gcc versions in debian:
$ g++-4.8 --version
g++-4.8 (Debian 4.8.3-9) 4.8.3
Copyright (C) 2013 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ g++-4.9 --version
g++-4.9 (Debian 4.9.1-9) 4.9.1
Copyright (C) 2014 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.