mozilla/rust — pull request #11768 by nikomatsakis (2014-01-24 08:19:53+00:00)
Title: Introduce marker types

Introduce marker types for indicating variance and for opting out
of builtin bounds.

Fixes #10834.
Fixes #11385.
cc #5922.

r? @pnkfelix (since you reviewed the variance inference in the first place)