Refactor feature gates#63855

Merged

bors merged 4 commits intorust-lang:masterfrom

killercup:refactor/feature-gates

Aug 27, 2019

Commits on Aug 24, 2019

Fix tidy feature gate error reporting
Pascal Hertleif
committed
Use doc comments for feature gate descriptions
Pascal Hertleif
committed

Commits on Aug 25, 2019

Introduce and use `Feature` type for feature gates
Pascal Hertleif
committed
Refactor feature gate checking code
Pascal Hertleif
committed