[Bug c++/59937] New: [constexpr] bogus diagnostic "used in its own initializer"

[richard-gccbugzilla at metafoo dot co.uk]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59937

            Bug ID: 59937
           Summary: [constexpr] bogus diagnostic "used in its own
                    initializer"
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: richard-gccbugzilla at metafoo dot co.uk

GCC rejects this:

constexpr const char * const &r = "";
constexpr const char * const &s = r;

with this bogus diagnostic:

test.cpp:2:35: error: the value of ‘r’ is not usable in a constant expression
 constexpr const char * const &s = r;
                                   ^
test.cpp:1:31: note: ‘r’ used in its own initializer
 constexpr const char * const &r = "";
                               ^