Why the extra impl for ZipSlices?

[SuperFluffy]

I was looking at the ZipSlices impl and noticed that you have the signatures impl<'a, 'b, A, B> ZipSlices<&'a [A], &'b [B]> and impl<T, U> ZipSlices<T, U> where T: Slice, U: Slice. The latter seems a lot more general, and I was wondering why the former is still in the library? Are there some non-trivial reasons for this?

[bluss]

Yes, the reason is that the non-general one will force coercions, so it will actually work with arguments like &Vec<T>, so it's easier to use. Only problem is I've basically inverted the names for the two methods..

[bluss]

If type parameter defaults change the story for coercions, we can talk about removing it, until then it's useful.

[bluss]

Type param defaults: rust-lang/rust/issues/27336