[Bug c++/90196] std:: types unused without warnings but simple type not affected

[maxim.prohorenko at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90196

--- Comment #5 from Максим Прохоренко <maxim.prohorenko at gmail dot com> ---

using namespace std;

class __attribute__((warn_unused)) kw
{
public:
  bitset<12> flags{"000000000010"};

};

int main() {
  printf("Hello World!\n");

  kw KW;
  puts(to_string(sizeof(kw)).c_str());
  return 0;
}

Mark all my class by __attribute__((warn_unused)) and all my colleagues was
hate me.