Ben Gamari authored Mar 07, 2017 and Ben Gamari committed Mar 07, 2017

As far as I can tell we were unnecessarily building a new TcgEnv when we
already had one on hand. TcRnMonad now sports an initTcWithGbl function,
which allows us to run a TcM monad in the context of this TcgEnv. This
appears to simplify things nicely.

Test Plan: Validate

Reviewers: austin

Subscribers: dfeuer, simonpj, thomie

Differential Revision: https://phabricator.haskell.org/D3228