[Bug c++/88413] g++ mangles names involving unresolved names in function argument template parameters differently from the ABI standard.

[brennan at umanwizard dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88413

--- Comment #2 from brennan at umanwizard dot com ---
I find the opposite, on whatever ancient version of c++filt ships with macOS:

$ c++filt --version
GNU c++filt 070207 20070207
Copyright 2005 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License.  This program has absolutely no warranty.

$ c++filt -n _Z1gIiEvP2S1IXsr2S2IT_EE3valEE
void g<int>(S1<S2<int>::val>*)

$ c++filt -n _Z1gIiEvP2S1IXsr2S2IT_E3valEE
_Z1gIiEvP2S1IXsr2S2IT_E3valEE

So either the change was introduced since that version of c++filt came out,
*or* Apple modified it to match clang...