http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60416
--- Comment #2 from Daniel Krügler <daniel.kruegler at googlemail dot com> --- I agree that this is unwanted, but I can deduce astonishing little information what the standard requires here. For copy/move operations we have at least 12.3.1 p3 saying "An implicitly-declared copy/move constructor is not an explicit constructor; it may be called for implicit type conversions." I would appreciate if we had a similar sentence for implicitly declared default constructors. IMO the absence of any information here leaves it open, at least this is my interpretation. I have the feeling that we lost this information after removing several of the requirements on defaulted member functions that was before specified by wording in 8.4: http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#906
