ekmett/void — pull request #3 by ehird (2012-12-02 18:27:54+00:00)
Title: Remove unsafe implementation of vacuous/vacuousM

Unfortunately, you can use GADTs to derive `unsafeCoerce` from this implementation; see http://hpaste.org/78660.

Perhaps the faster version should be exported as `unsafeVacuous`, possibly from another module (e.g. `Data.Void.Unsafe`)?