Rollup of 5 pull requests#63325

Closed

Centril wants to merge 23 commits intorust-lang:masterfrom

Centril:rollup-gaqv2nd

Commits on Jul 20, 2019

Commits on Jul 29, 2019

Use internal iteration in the Sum and Product impls of Result and Option
timvermeulen
committed

Commits on Aug 2, 2019

Commits on Aug 3, 2019

avoid mutable state and override main message
estebank
committed

Commits on Aug 5, 2019

Commits on Aug 6, 2019