error: implementation of `FnOnce` is not general enough
  --> $DIR/higher-ranked-auto-trait-15.rs:20:5
   |
LL |     require_send(future);
   |     ^^^^^^^^^^^^^^^^^^^^ implementation of `FnOnce` is not general enough
   |
   = note: closure with signature `fn(&'0 Vec<i32>) -> std::slice::Iter<'_, i32>` must implement `FnOnce<(&'1 Vec<i32>,)>`, for any two lifetimes `'0` and `'1`...
   = note: ...but it actually implements `FnOnce<(&Vec<i32>,)>`

error: implementation of `FnOnce` is not general enough
  --> $DIR/higher-ranked-auto-trait-15.rs:20:5
   |
LL |     require_send(future);
   |     ^^^^^^^^^^^^^^^^^^^^ implementation of `FnOnce` is not general enough
   |
   = note: closure with signature `fn(&'0 Vec<i32>) -> std::slice::Iter<'_, i32>` must implement `FnOnce<(&'1 Vec<i32>,)>`, for any two lifetimes `'0` and `'1`...
   = note: ...but it actually implements `FnOnce<(&Vec<i32>,)>`
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error: aborting due to 2 previous errors