Rollup of 5 pull requests#63739

Closed

Centril wants to merge 10 commits intorust-lang:masterfrom

Centril:rollup-h8r9paf

Commits on Aug 4, 2019

Implement nth_back for ChunksExactMut
JohnTitor
committed

Commits on Aug 6, 2019

avoid unnecessary reservations in std::io::Take::read_to_end
oconnor663
committed

Commits on Aug 18, 2019

Fix bug in iter::Chain::size_hint
timvermeulen
committed

Commits on Aug 20, 2019