error[E0106]: missing lifetime specifiers
  --> $DIR/missing-lt-for-hrtb.rs:2:32
   |
LL | struct S<'a>(&'a dyn Fn(&X) -> &X);
   |                         --     ^^ expected named lifetime parameter
   |                                |
   |                                expected named lifetime parameter
   |
   = help: this function's return type contains a borrowed value, but the signature does not say which one of argument 1's 2 lifetimes it is borrowed from
help: consider using the `'a` lifetime
   |
LL | struct S<'a>(&'a dyn Fn(&X) -> &'a X<'a>);
   |                                 ++  ++++

error[E0106]: missing lifetime specifiers
  --> $DIR/missing-lt-for-hrtb.rs:4:40
   |
LL | struct V<'a>(&'a dyn for<'b> Fn(&X) -> &X);
   |                                 --     ^^ expected named lifetime parameter
   |                                        |
   |                                        expected named lifetime parameter
   |
   = help: this function's return type contains a borrowed value, but the signature does not say which one of argument 1's 2 lifetimes it is borrowed from
note: these named lifetimes are available to use
  --> $DIR/missing-lt-for-hrtb.rs:4:10
   |
LL | struct V<'a>(&'a dyn for<'b> Fn(&X) -> &X);
   |          ^^              ^^
help: consider using one of the available lifetimes here
   |
LL | struct V<'a>(&'a dyn for<'b> Fn(&X) -> &'lifetime X<'lifetime>);
   |                                         +++++++++  +++++++++++

error: lifetime may not live long enough
  --> $DIR/missing-lt-for-hrtb.rs:10:9
   |
LL |     let x = S(&|x| {
   |                 -- return type of closure is &'2 X<'_>
   |                 |
   |                 has type `&'1 X<'_>`
LL |         println!("hi");
LL |         x
   |         ^ returning this value requires that `'1` must outlive `'2`

error: lifetime may not live long enough
  --> $DIR/missing-lt-for-hrtb.rs:10:9
   |
LL |     let x = S(&|x| {
   |                 -- return type of closure is &X<'4>
   |                 |
   |                 has type `&X<'3>`
LL |         println!("hi");
LL |         x
   |         ^ returning this value requires that `'3` must outlive `'4`

error: aborting due to 4 previous errors

For more information about this error, try `rustc --explain E0106`.