[clang] [clang] Allow constexpr-unknown values pre C++23 (PR #129646)

[Eli Friedman via cfe-commits]

Timm =?utf-8?q?B=C3=A4der?= <tbaeder at redhat.com>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/129646 at github.com>


efriedma-quic wrote:

Reduced testcase for the microsoft-abi-member-pointers.cpp failure:

```
constinit int &b = b;
```

This should produce an error; clang -std=c++23 currently accepts it.

https://github.com/llvm/llvm-project/pull/129646