error: unnecessary use of `to_string` --> app/src/app.rs:205:33 | 205 | .on_builtin(&engine.eth.url().to_string()) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `engine.eth.url().as_ref()` | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_to_owned = note: `-D clippy::unnecessary-to-owned` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(clippy::unnecessary_to_owned)]`