http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52718
--- Comment #15 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-11-01 20:52:15 UTC --- This is what I meant when I said that the issue is different, and is much more general than -Wzero-as-null-pointer-constant. Consider, eg, with -Woverflow: #pragma GCC system_header class Foo { public: Foo(signed char); }; class Bar { public: Bar(Foo = 10000); };