match_wild_err_arm triggers weirdly

[Lokathor]

If you match on Err(_) then it triggers the match_wild_err_arm lint and clippy tells you to match on each error individually, but if you match on Err(_e) it doesn't trigger at all, even though that's ignoring all possible errors just the same.

Code that brought this up

  #[inline]
  #[must_use]
  pub fn from_array_len(data: A, len: usize) -> Self {
    match Self::try_from_array_len(data, len) {
      Ok(out) => out,
      Err(_) => {
        panic!("ArrayishVec: length {} exceeds capacity {}!", len, A::CAPACITY)
      }
    }
  }

• This should probably only trigger on enum errors, not struct errors.
• Using a name other than _ will still match on everything, which is what this lint theoretically doesn't link, so alternate names should also still trigger the lint

[JohnTitor]

Actually, the lint description says it checks for arm which matches all errors with Err(_) so the identifiers like _e seem unintended.
But it might be nice that this lint also checks the identifiers which have _ as a prefix.

[flip1995]

We rarely have issues demanding that a lint should lint more, so I like this 😄

When linting on _e and similar, a check is required, that _e isn't used in the match arm though.