error[E0700]: hidden type for `impl Trait<'a, 'b>` captures lifetime that does not appear in bounds
  --> $DIR/ordinary-bounds-unsuited.rs:31:33
   |
LL | fn upper_bounds<'a, 'b>(a: Ordinary<'a>, b: Ordinary<'b>) -> impl Trait<'a, 'b>
   |                     --                                       ------------------ opaque type defined here
   |                     |
   |                     hidden type `Ordinary<'b>` captures the lifetime `'b` as defined here
...
LL |     if condition() { a } else { b }
   |                                 ^
   |
help: to declare that `impl Trait<'a, 'b>` captures `'b`, you can add an explicit `'b` lifetime bound
   |
LL | fn upper_bounds<'a, 'b>(a: Ordinary<'a>, b: Ordinary<'b>) -> impl Trait<'a, 'b> + 'b
   |                                                                                 ++++

error: aborting due to previous error

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