https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79433
Jonathan Wakely <redi at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Last reconfirmed| |2017-02-09 Summary|__has_include does not |__has_include(<new header>) |conform to SD-6 |is true but #include <new | |header> gives #error when | |-std=old Ever confirmed|0 |1 --- Comment #13 from Jonathan Wakely <redi at gcc dot gnu.org> --- Even SD-6 has a similar specification: The has-include-expression is replaced by the pp-number 1 if the search for the source file succeeds, and by the pp-number 0 if the search fails. It says nothing about whether inclusion would succeed, only whether the search for the file succeeds. It's implementation-defined how the search for source files is done. I'll confirm this as an enhancement for libstdc++, but insisting it's not conforming is simply wrong.