[Bug c++/87547] New: G++ reports bad type names for bit-field members

[sandro.boehler at gmx dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87547

            Bug ID: 87547
           Summary: G++ reports bad type names for bit-field members
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: sandro.boehler at gmx dot de
  Target Milestone: ---
              Host: i686-linux-gnu
            Target: i686-linux-gnu

Consider the following code:

#include <typeinfo>
struct S
{
    unsigned int n4  :  4;
    unsigned int n12 : 12;
};

void f(unsigned char)
{
    std::cout << "uc" << std::endl;
}

void f(unsigned short)
{
    std::cout << "us" << std::endl;
}

void f(unsigned int)
{
    std::cout << "ui" << std::endl;
}

int main(int argc, char* argv[])
{
    S s; s.n4 = 0; s.n12 = 0;
    f(s.n4);
    f(s.n12);
    std::cout << typeid(s.n4).name() << std::endl;
    std::cout << typeid(s.n12).name() << std::endl;
    std::cout << typeid(unsigned char).name() << std::endl;
    std::cout << typeid(unsigned short).name() << std::endl;
    std::cout << typeid(unsigned int).name() << std::endl;
    return 0;
}

Expected output (according to standard [class.bit]
(http://eel.is/c++draft/class.bit): "The bit-field attribute is not part of the
type of the class member."):

ui
ui
j
j
h
t
j

Output produced with g++ (Ubuntu 8.1.0-5ubuntu1~16.04) 8.1.0 (initially
discovered with 5.5.0):

ui
ui
h
t
h
t
j

So while the overload is selected correctly, typeid selects the bad type.

I did not test separately, but assume the compiler showing same behaviour for C
as well.