error[E0700]: hidden type for `impl PlusOne` captures lifetime that does not appear in bounds
  --> $DIR/imply_bounds_from_bounds_param.rs:24:5
   |
LL | fn test<'a>(y: &'a mut i32) -> impl PlusOne {
   |         --                     ------------ opaque type defined here
   |         |
   |         hidden type `<&'a mut i32 as Callable>::Output` captures the lifetime `'a` as defined here
LL |     <&'a mut i32 as Callable>::call(y)
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
help: to declare that `impl PlusOne` captures `'a`, you can add an explicit `'a` lifetime bound
   |
LL | fn test<'a>(y: &'a mut i32) -> impl PlusOne + 'a {
   |                                             ++++

error: aborting due to previous error

For more information about this error, try `rustc --explain E0700`.