[Bug c++/79937] [6/7/8 Regression] ICE in replace_placeholders_r

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79937

--- Comment #12 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 43577
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=43577&action=edit
gcc8-pr79937.patch

My #c8 patch doesn't work at all, but this one at least fixes the two testcases
(but indeed doesn't fix one where bar returns X rather than C).