[Bug c++/40335] New: The implement of Switch statment is against with C++ standard

["shenrfen at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

Source code: 1.cpp
#include <stdio.h>
static int i;

int
main (void)
{
  i = -1; 
  switch ((signed char) i) {
  case 255:
    printf("255\n");
    break;
  default:
    printf("default\n");
    break;
  }
}

Compiling command  : g++ 1.cpp && ./a.out
result             : 255
The expected result: default  

According to C++ standard, an integral promotion of expression "(signed char)
i" should be performed firstly, the result of control expression should be
0xffff; then the label of case statment will be converted to int-type. So the
expected result should be default in my opinion. 

Thanks very much.

C++ standard:
The condition shall be of integral type, enumeration type, or of a class type
for which a single conversion function to integral or enumeration type exists
(12.3). If the condition is of class type, the condition is converted by
calling that conversion function, and the result of the conversion is used in
place of the original condition for the remainder of this section. 
Integral promotions are performed.
Any statement within the switch statement can be labeled with one or more case
labels as follows:
case constant-expression :
where the constant-expression shall be an integral constant-expression. The
integral constant-expression (5.19) is implicitly converted to the promoted
type of the switch condition.


-- 
           Summary: The implement of Switch statment is against with C++
                    standard
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: critical
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: shenrfen at gmail dot com
 GCC build triplet: x86
  GCC host triplet: x86
GCC target triplet: x86


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40335