From f085cf39993a64c58e44eca50c37053d96b6115e Mon Sep 17 00:00:00 2001
From: Peter Simons <simons@cryp.to>
Date: Mon, 9 Jun 2014 09:49:07 +0200
Subject: [PATCH] haskell-snap: jailbreak to fix build with lens 4.2

---
 pkgs/development/libraries/haskell/snap/snap.nix | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/pkgs/development/libraries/haskell/snap/snap.nix b/pkgs/development/libraries/haskell/snap/snap.nix
index 97e4a4d67a5d..435bccd9cb5d 100644
--- a/pkgs/development/libraries/haskell/snap/snap.nix
+++ b/pkgs/development/libraries/haskell/snap/snap.nix
@@ -20,6 +20,9 @@ cabal.mkDerivation (self: {
     unorderedContainers vector vectorAlgorithms xmlhtml
   ];
   jailbreak = true;
+  patchPhase = ''
+    sed -i -e 's|lens .*< 4.2|lens|' snap.cabal
+  '';
   meta = {
     homepage = "http://snapframework.com/";
     description = "Top-level package for the Snap Web Framework";