warning: unnecessary parentheses around type
       --> tests/test.rs:904:20
        |
    904 |     impl Trait for (dyn Fn(u8) + Send + Sync) {
        |                    ^                        ^
        |
        = note: `#[warn(unused_parens)]` on by default
    help: remove these parentheses
        |
    904 -     impl Trait for (dyn Fn(u8) + Send + Sync) {
    904 +     impl Trait for dyn Fn(u8) + Send + Sync {
        |

This reverts commit f9b2b21.