From 237b0162bd0c947385ffc1065ad20a78f48e29bc Mon Sep 17 00:00:00 2001
From: Luke Murphy <lukewm@riseup.net>
Date: Sun, 20 Aug 2017 13:32:47 +0200
Subject: [PATCH] Install happy for style builds.

Motivated from this build failure on HEAD:

  * https://travis-ci.org/commercialhaskell/stack/jobs/266365181

Related to https://github.com/commercialhaskell/stack/issues/3178.

This fix is based on a comments from:

  * https://github.com/commercialhaskell/stack/issues/3178#issuecomment-306405297
  * https://github.com/commercialhaskell/stack/issues/3151#issuecomment-313126596
---
 .travis.yml | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/.travis.yml b/.travis.yml
index 4ab10b5d19..7979575af7 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -78,6 +78,10 @@ install:
    set -ex
    case "$BUILD" in
      style)
+       # This should be resolved (and removed) by Stack 1.6
+       # Follows from https://github.com/commercialhaskell/stack/issues/3178
+       stack --system-ghc --no-terminal install happy
+
        stack --system-ghc --no-terminal install hlint
        ;;
      stack)