error: `impl Trait` captures lifetime parameter, but it is not mentioned in `use<...>` precise captures list
  --> $DIR/forgot-to-capture-lifetime.rs:3:52
   |
LL | fn lifetime_in_bounds<'a>(x: &'a ()) -> impl Into<&'a ()> + use<> { x }
   |                       --                -----------^^------------
   |                       |                 |
   |                       |                 lifetime captured due to being mentioned in the bounds of the `impl Trait`
   |                       this lifetime parameter is captured

error[E0700]: hidden type for `impl Sized` captures lifetime that does not appear in bounds
  --> $DIR/forgot-to-capture-lifetime.rs:6:62
   |
LL | fn lifetime_in_hidden<'a>(x: &'a ()) -> impl Sized + use<> { x }
   |                       --                ------------------   ^
   |                       |                 |
   |                       |                 opaque type defined here
   |                       hidden type `&'a ()` captures the lifetime `'a` as defined here
   |
help: to declare that `impl Sized` captures `'a`, you can add an explicit `'a` lifetime bound
   |
LL | fn lifetime_in_hidden<'a>(x: &'a ()) -> impl Sized + use<> + 'a { x }
   |                                                            ++++

error: aborting due to 2 previous errors

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