https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120025
--- Comment #7 from Stas Sergeev <stsp at users dot sourceforge.net> --- (In reply to Andrew Pinski from comment #6) > So the big problem with this extension is that it will not work with > concepts (and SFINAE) in a decent form. This is why the extension was > removed in the first place. ... > Right now GCC does the correct thing even for -fpermissive. Isn't this self-contradictory? I tried your example and indeed, static_assert fails regardless of -fpermissive. Which means to me that this extension was implemented the way not to modify the behavior of concepts and SFINAE, and therefore was undefaulted not for that reason.
