[libcxx-commits] [libcxx] [libc++] Remove SFINAE on __tuple_impl constructors (PR #151654)

[A. Jiang via libcxx-commits]

frederick-vs-ja wrote:

Aha, I've reduced the example to:

```C++
template<class>
struct Trait;

template<class T>
constexpr bool TraitV = Trait<T>::value;

template<class T>
struct S {
    S() noexcept(TraitV<T>) = default;
};

template<class T>
struct S2 : S<T> {};

S2<char> s;
```

[Godbolt link](https://gcc.godbolt.org/z/1aMfzr435)

This should be https://github.com/llvm/llvm-project/labels/crash-on-invalid.

https://github.com/llvm/llvm-project/pull/151654