error[E0207]: the lifetime parameter `'a` is not constrained by the impl trait, self type, or predicates --> $DIR/impl-unused-rps-in-assoc-type.rs:11:6 | LL | impl<'a> Fun for Holder { | ^^ unconstrained lifetime parameter error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0207`.