error[E0599]: no method named `count` found for struct `Filter<Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:7:39: 7:53]>` in the current scope
  --> $DIR/issue-36053-2.rs:7:55
   |
LL |     once::<&str>("str").fuse().filter(|a: &str| true).count();
   |                                       --------------  ^^^^^ method not found in `Filter<Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:7:39: 7:53]>`
   |                                       |
   |                                       doesn't satisfy `<_ as FnOnce<(&&str,)>>::Output = bool`
   |                                       doesn't satisfy `_: FnMut<(&&str,)>`
   | 
  ::: $SRC_DIR/core/src/iter/adapters/mod.rs:LL:COL
   |
LL | pub struct Filter<I, P> {
   | ----------------------- doesn't satisfy `_: Iterator`
   |
   = note: the method `count` exists but the following trait bounds were not satisfied:
           `<[closure@$DIR/issue-36053-2.rs:7:39: 7:53] as FnOnce<(&&str,)>>::Output = bool`
           which is required by `Filter<Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:7:39: 7:53]>: Iterator`
           `[closure@$DIR/issue-36053-2.rs:7:39: 7:53]: FnMut<(&&str,)>`
           which is required by `Filter<Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:7:39: 7:53]>: Iterator`
           `Filter<Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:7:39: 7:53]>: Iterator`
           which is required by `&mut Filter<Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:7:39: 7:53]>: Iterator`

error[E0631]: type mismatch in closure arguments
  --> $DIR/issue-36053-2.rs:7:32
   |
LL |     once::<&str>("str").fuse().filter(|a: &str| true).count();
   |                                ^^^^^^ -------------- found signature of `for<'r> fn(&'r str) -> _`
   |                                |
   |                                expected signature of `for<'r> fn(&'r &str) -> _`

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0599, E0631.
For more information about an error, try `rustc --explain E0599`.