I couldn't find it in the API guidelines either. From what I understand, the idea is that any trait bounds, which includes generic type parameter bounds and lif

I couldn't find it in the API guidelines either. From what I understand, the idea is that any trait bounds, which includes generic type parameter bounds and lifetime bound on a type (struct or enum) would be repeated back in the impl block there is a nice discussion on this issue here: https://github.com/rust-lang/rust-clippy/issues/1689 https://github.com/rust-lang/rust-clippy/issues/1689