The diagnostics for `enable_if_t` are extremely opaque:
```
error: no matching function for call to 'bind_front'
note: candidate template ignored: requirement 'integral_constant<bool, false>::value' was not satisfied
```
Using requires-expressions gives us a little more context:
```
error: no matching function for call to 'bind_front'
note: candidate template ignored: constraints not satisfied
note: because 'is_constructible_v<decay_t<T &>, T &>' evaluated to false
```
Pull request: #68249
48c805bafd