[Bug c++/55643] [4.7/4.8 Regression] [C++11] incorrect "warning: variable ‘myVar’ set but not used" with an "enum class"-typed variable is casted to double for the use

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55643

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |diagnostic
            Version|unknown                     |4.7.2
            Summary|[4.7/4.8 Regression] g++    |[4.7/4.8 Regression]
                   |incorrectly prints          |[C++11] incorrect
                   |"warning: variable ‘myVar’  |"warning: variable ‘myVar’
                   |set but not used            |set but not used" with an
                   |[-Wunused-but-set-variable] |"enum class"-typed variable
                   |" when an "enum             |is casted to double for the
                   |class"-typed variable is    |use
                   |cast to double before use   |

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-12-10 
23:54:04 UTC ---
Here is a small testcase without any includes:
enum class MyEnum
{
  eSomeValue = 123
};

void f(const char*, ...);

int main() {

  MyEnum myVar = MyEnum::eSomeValue;

  // As far as Wunused-but-set-variable is concerned, any of the following
  // will successfully "use" myVar:
  //  printf("%d\n", myVar);
  //  printf("%d\n", (int)myVar);
  //  printf("%u\n", (unsigned)myVar);

  // ...but these do not:
  f("%f\n", (double)myVar);
  f("%f\n", (float)myVar);

  return 0;
}