https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63924
--- Comment #6 from Jason Merrill <jason at gcc dot gnu.org> --- (In reply to Nikos from comment #5) > I am sorry, it is missing from the original test case, but > > noop< > require_costexpr< size0(ar) >, > require_constexp< size1(ar) > > >(); > > compiles fine. Yes, because ar is a constexpr variable. The parameter 't' of size3 is not a constexpr variable. When compiling a constexpr function, the parameters are not constant; only in a call to that function are the parameters (sometimes) replaced by constants. Remember that a constexpr function is still a normal function, and can be called with non-constant arguments. I agree that the compiler should treat the implicit trivial constructor the same as the user-defined constructor.
