Parameter usage is not properly propagated through trait aliases #74093
Description
It seems to me that both S1 and S2 should compile:
#![feature(trait_alias)] // Works struct S1<'a, T: 'a, I: Iterator<Item = &'a T> + Clone> { field: I, } trait SpecialIterator<'a, T: 'a> = Iterator<Item = &'a T> + Clone; // Doesn't work struct S2<'a, T: 'a, I: SpecialIterator<'a, T>> { field: I, }Playground. On 1.46.0-nightly (2020-07-05 2753fab7ce3647033146).