Rollup of 5 pull requests#64313

Merged

bors merged 10 commits intorust-lang:masterfrom

Centril:rollup-7w8b67g

Sep 9, 2019

Commits on Sep 4, 2019

Override `StepBy::{try_fold, try_rfold}`
timvermeulen
committed

Commits on Sep 9, 2019