[Bug c++/119339] New: Allows invalid constexpr of addresses with references initialized to itself

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119339

            Bug ID: 119339
           Summary: Allows invalid constexpr of addresses with references
                    initialized to itself
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Keywords: accepts-invalid
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
            Blocks: 55004
  Target Milestone: ---

Take:
```
constexpr int f() { int &a = a; return &a+1-&a; }
constexpr int z = f();
```

This should be rejected. as &a does not really point anywhere.

Forwarded from https://github.com/llvm/llvm-project/issues/131654 .


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55004
[Bug 55004] [meta-bug] constexpr issues