Replace a match with some as_ref and as

The match was doing a deref coercion.

Found by current nightly's needless_match (whose suggestion doesn't compile, https://github.com/rust-lang/rust-clippy/issues/8551 )

assigned to @Diziet

LGTM.

I've never seen expr as _ before...

requested review from @nickm

enabled an automatic merge when the pipeline for 7564fabd succeeds

merged

mentioned in commit 3e12cf26