Rollup of 6 pull requests#60969

Merged

bors merged 23 commits intorust-lang:masterfrom

Centril:rollup-3j71mqj

May 20, 2019

Commits on May 6, 2019

Test interaction of unions with non-zero/niche-filling optimization
petertodd
committed

Commits on May 7, 2019

Commits on May 15, 2019

Update lib.rs
chandde
authored

Commits on May 16, 2019

add targetarch for CodegenContext
chandde
committed

Commits on May 19, 2019