error[E0700]: hidden type for `impl IntoIterator<Item = impl Cap<'a> + Cap<'b>>` captures lifetime that does not appear in bounds
  --> $DIR/nested-impl-trait-fail.rs:17:5
   |
LL | fn fail_early_bound<'s, 'a, 'b>(a: &'s u8) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>>
   |                     --                        ------------------------------------------------ opaque type defined here
   |                     |
   |                     hidden type `[&'s u8; 1]` captures the lifetime `'s` as defined here
...
LL |     [a]
   |     ^^^
   |
help: to declare that `impl IntoIterator<Item = impl Cap<'a> + Cap<'b>>` captures `'s`, you can add an explicit `'s` lifetime bound
   |
LL | fn fail_early_bound<'s, 'a, 'b>(a: &'s u8) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>> + 's
   |                                                                                                ++++
help: to declare that `impl Cap<'a> + Cap<'b>` captures `'s`, you can add an explicit `'s` lifetime bound
   |
LL | fn fail_early_bound<'s, 'a, 'b>(a: &'s u8) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b> + 's>
   |                                                                                               ++++

error[E0700]: hidden type for `impl Cap<'a> + Cap<'b>` captures lifetime that does not appear in bounds
  --> $DIR/nested-impl-trait-fail.rs:17:5
   |
LL | fn fail_early_bound<'s, 'a, 'b>(a: &'s u8) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>>
   |                     --                                                 ---------------------- opaque type defined here
   |                     |
   |                     hidden type `&'s u8` captures the lifetime `'s` as defined here
...
LL |     [a]
   |     ^^^
   |
help: to declare that `impl IntoIterator<Item = impl Cap<'a> + Cap<'b>>` captures `'s`, you can add an explicit `'s` lifetime bound
   |
LL | fn fail_early_bound<'s, 'a, 'b>(a: &'s u8) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>> + 's
   |                                                                                                ++++
help: to declare that `impl Cap<'a> + Cap<'b>` captures `'s`, you can add an explicit `'s` lifetime bound
   |
LL | fn fail_early_bound<'s, 'a, 'b>(a: &'s u8) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b> + 's>
   |                                                                                               ++++

error[E0700]: hidden type for `impl IntoIterator<Item = impl Cap<'a> + Cap<'b>>` captures lifetime that does not appear in bounds
  --> $DIR/nested-impl-trait-fail.rs:28:5
   |
LL | fn fail_late_bound<'s, 'a, 'b>(
   |                    -- hidden type `[&'s u8; 1]` captures the lifetime `'s` as defined here
...
LL | ) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>> {
   |      ------------------------------------------------ opaque type defined here
LL |     [a]
   |     ^^^
   |
help: to declare that `impl IntoIterator<Item = impl Cap<'a> + Cap<'b>>` captures `'s`, you can add an explicit `'s` lifetime bound
   |
LL | ) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>> + 's {
   |                                                       ++++
help: to declare that `impl Cap<'a> + Cap<'b>` captures `'s`, you can add an explicit `'s` lifetime bound
   |
LL | ) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b> + 's> {
   |                                                      ++++

error[E0700]: hidden type for `impl Cap<'a> + Cap<'b>` captures lifetime that does not appear in bounds
  --> $DIR/nested-impl-trait-fail.rs:28:5
   |
LL | fn fail_late_bound<'s, 'a, 'b>(
   |                    -- hidden type `&'s u8` captures the lifetime `'s` as defined here
...
LL | ) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>> {
   |                               ---------------------- opaque type defined here
LL |     [a]
   |     ^^^
   |
help: to declare that `impl IntoIterator<Item = impl Cap<'a> + Cap<'b>>` captures `'s`, you can add an explicit `'s` lifetime bound
   |
LL | ) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>> + 's {
   |                                                       ++++
help: to declare that `impl Cap<'a> + Cap<'b>` captures `'s`, you can add an explicit `'s` lifetime bound
   |
LL | ) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b> + 's> {
   |                                                      ++++

error: aborting due to 4 previous errors

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