[Bug c++/57943] [c++11] invalid decltype expression accepted in template default type

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57943

--- Comment #2 from Martin Sebor <msebor at gcc dot gnu.org> ---
*** Bug 89874 has been marked as a duplicate of this bug. ***