1 error: methods called `as_*` usually take `self` by reference or `self` by mutable reference
2 --> $DIR/def_id_nocore.rs:26:19
4 LL | pub fn as_ref(self) -> &'static str {
7 = note: `-D clippy::wrong-self-convention` implied by `-D warnings`
8 = help: consider choosing a less ambiguous name
10 error: aborting due to previous error