[Bug c++/47108] New: enum won't use long long as underlying type

[flo.ruijt at hotmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47108

           Summary: enum won't use long long as underlying type
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: flo.ruijt@hotmail.com


c++0x introduce long long, which should be used as the base type for enum if on
of the enumerators doesn't fit in int, 7.2.6:

  For an enumeration whose underlying type is not fixed, the underlying type is
an integral type that can
6
  represent all the enumerator values defined in the enumeration. If no
integral type can represent all the
  enumerator values, the enumeration is ill-formed. It is
implementation-defined which integral type is used
  as the underlying type except that the underlying type shall not be larger
than int unless the value of an
  enumerator cannot fit in an int or unsigned int. If the enumerator-list is
empty, the underlying type is
  as if the enumeration had a single enumerator with value 0.

the folowing program demonstrates the bug, note that gcc does give a warning:

#include <iostream>
int main(){
    enum{ waf=1<<33 }blaf;
    std::cout<<sizeof(blaf)<<'\n';
}

it will print 4 meaning it chose int as the underlying type which is wrong
because 1<<33 doesn't fit in int but it does in long long so it should've
chosen that instead.

note that this doesn't apply for strict c++98 as it requires no long long type.
it should probably be fixed anyway