previously, we would warn like this: ```` warning: lifetime parameter `'s` never used --> /tmp/unusedlif/code.rs:6:62 | 5 | #[derive(Clone)] | - help: elide the unused lifetime 6 | struct ShimMethod4<T: Trait2 + 'static>(pub &'static dyn for<'s> Fn(&'s mut T::As)); | ^^ | = note: requested on the command line with `-W unused-lifetimes` ```` Fixes #104432
