[Bug c++/114705] New: [DR 2763] Warn about [[noreturn]] that returns during constant evaluation

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114705

            Bug ID: 114705
           Summary: [DR 2763] Warn about [[noreturn]] that returns during
                    constant evaluation
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mpolacek at gcc dot gnu.org
  Target Milestone: ---

clang++ warns here:

```
[[noreturn]] constexpr void f() {}
constexpr int x = (f(), 0);
```

l.C:1:36: warning: function declared 'noreturn' should not return
[-Winvalid-noreturn]
    1 |   [[noreturn]] constexpr void f() {}
      |                                    ^

but we don't.

Related to https://cplusplus.github.io/CWG/issues/2763.html