Rufflewind authored Mar 15, 2017 and Ben Gamari committed Mar 15, 2017

Summary:
Keep track of column numbers and inform GHC whenever the column number
could be potentially desynchronized from the original source code.  This
should fix GHC #13388 on Trac.

Test Plan: validate

Reviewers: O25 HSC2HS, hvr, bgamari

Reviewed By: bgamari

Differential Revision: https://phabricator.haskell.org/D3314