warning: the feature `precise_capturing` is incomplete and may not be safe to use and/or cause compiler crashes
  --> $DIR/forgot-to-capture-lifetime.rs:1:12
   |
LL | #![feature(precise_capturing)]
   |            ^^^^^^^^^^^^^^^^^
   |
   = note: see issue #123432 <https://github.com/rust-lang/rust/issues/123432> for more information
   = note: `#[warn(incomplete_features)]` on by default

error: `impl Trait` captures lifetime parameter, but it is not mentioned in `use<...>` precise captures list
  --> $DIR/forgot-to-capture-lifetime.rs:4:58
   |
LL | fn lifetime_in_bounds<'a>(x: &'a ()) -> impl use<> Into<&'a ()> { 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:7:60
   |
LL | fn lifetime_in_hidden<'a>(x: &'a ()) -> impl use<> Sized { 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 use<> Sized + 'a { x }
   |                                                          ++++

error: aborting due to 2 previous errors; 1 warning emitted

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