mozilla/rust — pull request #14768 by riccieri (2014-06-09 08:17:10+00:00)
Title: Remove & -> &mut transmutation from libarena

Changes both `Arena` and `TypedArena` to contain an inner struct wrapped in a `Unsafe`, and change field access to go through those instead of transmuting `&self` to `&mut self`.

Part of #13933