From bd46cb180d24637b95b06f5bbce7c467f71dcd92 Mon Sep 17 00:00:00 2001
From: Peter Simons <simons@cryp.to>
Date: Mon, 12 Mar 2018 11:06:29 +0100
Subject: [PATCH] haskell-vty: use latest version when compiling with GHC 8.4.x

---
 pkgs/development/haskell-modules/configuration-ghc-8.4.x.nix | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/pkgs/development/haskell-modules/configuration-ghc-8.4.x.nix b/pkgs/development/haskell-modules/configuration-ghc-8.4.x.nix
index 9d4b632edba..d216e8a41a0 100644
--- a/pkgs/development/haskell-modules/configuration-ghc-8.4.x.nix
+++ b/pkgs/development/haskell-modules/configuration-ghc-8.4.x.nix
@@ -795,4 +795,7 @@ self: super: {
       stripLen = 1;
     });
 
+  # Old versions don't compile.
+  vty = self.vty_5_20;
+
 }