mozilla/rust — pull request #9703 by alexcrichton (2013-10-03 16:13:04+00:00)
Title: Compiler #[feature] directives

This implements the necessary logic for gating particular features off by default in the compiler. There are a number of issues which have been wanting this form of mechanism, and this initially gates features which we have open issues for.

Additionally, this should unblock #9255