error: struct `OneOrMany` has a public `len` method, but no `is_empty` method --> rig-core/src/one_or_many.rs:36:5 | 36 | pub fn len(&self) -> usize { | ^^^^^^^^^^^^^^^^^^^^^^^^^^ | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#len_without_is_empty = note: `-D clippy::len-without-is-empty` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(clippy::len_without_is_empty)]`