> Higher-ranked projections (send bound problem, part 4)
https://smallcultfollowing.com/babysteps/blog/2023/06/12/higher-ranked-projections-send-bound-problem-part-4/
> the compiler won’t let you write things like `T::Item::Item` […] There’s no particularly good reason for this.
これ、今まで何か本質的な理由があるのだとばかり思っていた