Crash when evaluating a constexpr static function template in an incomplete class context.

[cor3ntin]

struct  s{
  static constexpr auto f(auto extent) {
    return 0;
  }

  static constexpr auto a = f(0);
};

The following crashes after clang 17.

https://godbolt.org/z/o7zaK7qKq

I's unclear whether this should be well-formed (see #73232)

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: cor3ntin (cor3ntin)

```cpp struct s{ static constexpr auto f(auto extent) { return 0; }

static constexpr auto a = f(0);
};

The following crashes after clang 17.

https://godbolt.org/z/o7zaK7qKq


I's unclear whether this should be well-formed (see #<!-- -->73232)



</details>

[shafik]

Confirmed.

Maybe duplicate of: #84522