[Bug c++/120155] ICE with generic lambda return type with a decltype of statement expression

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120155

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Without using a generic lambda (auto), GCC gives this error message:
```
<source>: In function 'void fun()':
<source>:6:17: error: ISO C++ forbids in-class initialization of non-const
static member 'fun()::<lambda>::a'
    6 |             int a = 1;
      |                 ^
```