https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124214
--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> --- This changed with r12-5287: c++: Add -fimplicit-constexpr With each successive C++ standard the restrictions on the use of the constexpr keyword for functions get weaker and weaker; it recently occurred to me that it is heading toward the same fate as the C register keyword, which was once useful for optimization but became obsolete. Similarly, it seems to me that we should be able to just treat inlines as constexpr functions and not make people add the extra keyword everywhere. There were a lot of testcase changes needed; many disabling errors about non-constexpr functions that are now constexpr, and many disabling implicit constexpr so that the tests can check the same thing as before, whether that's mangling or whatever.
