[Bug c++/120287] [15/16 Regression] internal compiler error: tree check: expected class 'type', have 'exceptional' (error_mark) in is_std_substitution, at cp/mangle.cc:507 since r15-2798

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120287

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2025-05-15
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed. Slightly more reduced (removing some C++20 features even):
```
namespace std
{
template<int a>
  auto m = []{}();
}
auto t = std::m<1>;
```

But this above one dates before GCC 15 at least back to GCC 10.