http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58408
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
If you make it constexpr, which requires you to initialize the member, then it
works:
class Test {
public:
constexpr Test() = default;
Test(char *b) { }
int i = 0;
};
Clang accepts both that and your original.
