[Bug c++/120880] New: g++: internal compiler error: Segmentation fault since 10.1 only with -std=c++20

[mario.rodriguezb1 at um dot es via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120880

            Bug ID: 120880
           Summary: g++: internal compiler error: Segmentation fault since
                    10.1 only with -std=c++20
           Product: gcc
           Version: 16.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mario.rodriguezb1 at um dot es
  Target Milestone: ---

Only happens with -std=c++20

Program:

```
int main()
{
    [](decltype(([]() -> int {})) f) {}();
}
```

Stack dump:

```
g++: internal compiler error: Segmentation fault signal terminated program
cc1plus
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
See <https://gcc.gnu.org/bugs/> for instructions.
Compiler returned: 4
```

To quickly reproduce:

https://godbolt.org/z/6Kf56fT8j