Rollup of 16 pull requests#55012

Merged

bors merged 37 commits intorust-lang:masterfrom

Oct 12, 2018

Commits on Oct 2, 2018

Commits on Oct 4, 2018

Fix #24840: make default for `optimize` independent of `debug` setting in `Cargo.toml`.
pnkfelix
committed

Commits on Oct 5, 2018

Add doc comments about safest way to initialize a vector of zeros
mandeep
committed

Commits on Oct 7, 2018

Fix tracking issue for Once::is_completed
SimonSapin
authored

Commits on Oct 9, 2018

Refactor macro comment and add resize with zeros example
mandeep
committed

Commits on Oct 12, 2018