[Bug c++/61471] redeclaration of default-argument in function template declaration not caught

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61471

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Oops, I messed up my test - we don't diagnose this even at instantiation