error[E0478]: lifetime bound not satisfied --> $DIR/regions-wf-trait-object.rs:7:8 | LL | x: Box+'b> | ^^^^^^^^^^^^^^^^^^^^^^^^ | note: lifetime parameter instantiated with the lifetime `'b` as defined here --> $DIR/regions-wf-trait-object.rs:6:15 | LL | struct Foo<'a,'b> { | ^^ note: but lifetime parameter must outlive the lifetime `'a` as defined here --> $DIR/regions-wf-trait-object.rs:6:12 | LL | struct Foo<'a,'b> { | ^^ error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0478`.