From 26974e962ebc5c1e3dfd8f6a84402ad72dc43d24 Mon Sep 17 00:00:00 2001
From: Peter Simons <simons@cryp.to>
Date: Wed, 24 Oct 2018 21:49:32 +0200
Subject: [PATCH] cabal2nix: fix build with ghc 8.4.x

---
 pkgs/development/haskell-modules/configuration-ghc-8.4.x.nix | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

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 052779e9a1e..213651405f3 100644
--- a/pkgs/development/haskell-modules/configuration-ghc-8.4.x.nix
+++ b/pkgs/development/haskell-modules/configuration-ghc-8.4.x.nix
@@ -63,12 +63,11 @@ self: super: {
   # more verbose but friendlier for Hydra.
   stack = (doJailbreak super.stack).override {
     Cabal = self.Cabal_2_4_0_1;
-    hpack = self.hpack_0_31_0;
+    hpack = self.hpack_0_31_0.override { Cabal = self.Cabal_2_4_0_1; };
     yaml = self.yaml_0_11_0_0;
     hackage-security = self.hackage-security.override { Cabal = self.Cabal_2_4_0_1; };
   };
   hpack_0_31_0 = super.hpack_0_31_0.override {
-    Cabal = self.Cabal_2_4_0_1;
     yaml = self.yaml_0_11_0_0;
   };