error: lifetime may not live long enough --> $DIR/issue-55796.rs:16:9 | LL | pub trait Graph<'a> { | -- lifetime `'a` defined here ... LL | Box::new(self.out_edges(u).map(|e| e.target())) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ returning this value requires that `'a` must outlive `'static` error: lifetime may not live long enough --> $DIR/issue-55796.rs:21:9 | LL | pub trait Graph<'a> { | -- lifetime `'a` defined here ... LL | Box::new(self.in_edges(u).map(|e| e.target())) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ returning this value requires that `'a` must outlive `'static` error: aborting due to 2 previous errors