http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58338
bredelin at ucla dot edu changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |bredelin at ucla dot edu --- Comment #10 from bredelin at ucla dot edu --- It seems that these changes (see Sep 17th) also made the default constructor explicit. While this does follow the standard, it is the subject of this defect report: http://cplusplus.github.io/LWG/lwg-active.html#2193 Was this change intentional?