[Bug c++/94255] template specialization in different namespace causes crash

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94255

--- Comment #6 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Patch approved for GCC 11:
https://gcc.gnu.org/pipermail/gcc-patches/2020-April/544081.html