I propose that we remove the following non-standard traits in GCC 7:
/// has_trivial_default_constructor (temporary legacy) template<typename _Tp> struct has_trivial_default_constructor : public integral_constant<bool, __has_trivial_constructor(_Tp)> { } _GLIBCXX_DEPRECATED; /// has_trivial_copy_constructor (temporary legacy) template<typename _Tp> struct has_trivial_copy_constructor : public integral_constant<bool, __has_trivial_copy(_Tp)> { } _GLIBCXX_DEPRECATED; /// has_trivial_copy_assign (temporary legacy) template<typename _Tp> struct has_trivial_copy_assign : public integral_constant<bool, __has_trivial_assign(_Tp)> { } _GLIBCXX_DEPRECATED; They were in C++0x drafts but were removed before the final C++11 standard, so have never been part of ISO C++. They've been deprecated since GCC 5.1: https://gcc.gnu.org/gcc-5/changes.html People who need that functionality can still use the built-ins directly, we don't need to define non-standard traits. Alternatively, we could move them to __gnu_cxx, so they don't pollute the namespace by default, or only define them when __STRICT_ANSI__ is not defined. I prefer simply removing them.