[Bug c++/84970] [8 Regression] ICE in tsubst_copy, at cp/pt.c:15085

[nathan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84970

--- Comment #2 from Nathan Sidwell <nathan at gcc dot gnu.org> ---
Created attachment 43720
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=43720&action=edit
The testcase can be morphed into well-formed code