nested bounds on traits aren't properly checked #5886
Description
U: Iterator<U> is used in the trait and U: Iterator<B> in the impl
trait Iterator<A> {
fn next(&mut self) -> Option<A>;
}
trait IteratorUtil<A> {
fn zip<B, U: Iterator<U>>(self, other: U) -> ZipIterator<Self, U>;
}
impl<A, T: Iterator<A>> IteratorUtil<A> for T {
fn zip<B, U: Iterator<B>>(self, other: U) -> ZipIterator<T, U> {
ZipIterator{a: self, b: other}
}
}
struct ZipIterator<T, U> {
a: T, b: U
}