error[E0599]: the method `filterx` exists for struct `Map<Repeat, [closure@issue-30786.rs:119:27]>`, but its trait bounds were not satisfied
  --> $DIR/issue-30786.rs:120:22
   |
LL | pub struct Map<S, F> {
   | --------------------
   | |
   | method `filterx` not found for this struct
   | doesn't satisfy `_: StreamExt`
...
LL |     let filter = map.filterx(|x: &_| true);
   |                      ^^^^^^^ method cannot be called on `Map<Repeat, [closure@issue-30786.rs:119:27]>` due to unsatisfied trait bounds
   |
note: the following trait bounds were not satisfied:
      `&'a mut &Map<Repeat, [closure@$DIR/issue-30786.rs:119:27: 119:34]>: Stream`
      `&'a mut &mut Map<Repeat, [closure@$DIR/issue-30786.rs:119:27: 119:34]>: Stream`
      `&'a mut Map<Repeat, [closure@$DIR/issue-30786.rs:119:27: 119:34]>: Stream`
  --> $DIR/issue-30786.rs:98:50
   |
LL | impl<T> StreamExt for T where for<'a> &'a mut T: Stream {}
   |         ---------     -                          ^^^^^^ unsatisfied trait bound introduced here

error[E0599]: the method `countx` exists for struct `Filter<Map<Repeat, fn(&u64) -> &u64 {identity::<u64>}>, [closure@issue-30786.rs:131:30]>`, but its trait bounds were not satisfied
  --> $DIR/issue-30786.rs:132:24
   |
LL | pub struct Filter<S, F> {
   | -----------------------
   | |
   | method `countx` not found for this struct
   | doesn't satisfy `_: StreamExt`
...
LL |     let count = filter.countx();
   |                        ^^^^^^ method cannot be called due to unsatisfied trait bounds
   |
note: the following trait bounds were not satisfied:
      `&'a mut &Filter<Map<Repeat, for<'a> fn(&'a u64) -> &'a u64 {identity::<u64>}>, [closure@$DIR/issue-30786.rs:131:30: 131:37]>: Stream`
      `&'a mut &mut Filter<Map<Repeat, for<'a> fn(&'a u64) -> &'a u64 {identity::<u64>}>, [closure@$DIR/issue-30786.rs:131:30: 131:37]>: Stream`
      `&'a mut Filter<Map<Repeat, for<'a> fn(&'a u64) -> &'a u64 {identity::<u64>}>, [closure@$DIR/issue-30786.rs:131:30: 131:37]>: Stream`
  --> $DIR/issue-30786.rs:98:50
   |
LL | impl<T> StreamExt for T where for<'a> &'a mut T: Stream {}
   |         ---------     -                          ^^^^^^ unsatisfied trait bound introduced here

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0599`.