[Bug c++/101155] New: comparing non-capturing lambdas is not constexpr

[ldalessandro at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101155

            Bug ID: 101155
           Summary: comparing non-capturing lambdas is not constexpr
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ldalessandro at gmail dot com
  Target Milestone: ---

I think the following function pointer comparison should be constexpr.

```
auto a = []{};
auto b = []{};
static_assert(a != b); // error: '(<lambda()>::_FUN != <lambda()>::_FUN)' is
not a constant expression

```

CE example: https://godbolt.org/z/avqPhrc6G