[Bug c++/88761] [8/9 Regression] ICE in tsubst_copy, at cp/pt.c:15478 when chaining lambda calls & fold-expressions

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88761

--- Comment #4 from Jason Merrill <jason at gcc dot gnu.org> ---
The #c0 and #c2 testcases are already fixed, but the #c3 testcase still breaks,
so I'm going to treat this PR as being about that one.