From f8c8bb04a5a89a2c0221b7616fa5ff5392822f85 Mon Sep 17 00:00:00 2001
From: sternenseemann <0rpkxez4ksa01gb3typccl0i@systemli.org>
Date: Thu, 10 Jun 2021 15:35:50 +0200
Subject: [PATCH] haskell.packages.ghc901.mono-traversable: unbreak

GHC 9.0.x seems to require that the `Main` module also defines the
`main` IO action and does not just import it. This is the case with
mono-traversable's test suite which is why we (temporarily) disable it.
---
 pkgs/development/haskell-modules/configuration-ghc-9.0.x.nix | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pkgs/development/haskell-modules/configuration-ghc-9.0.x.nix b/pkgs/development/haskell-modules/configuration-ghc-9.0.x.nix
index 401dc05fe836..5dea75bb2184 100644
--- a/pkgs/development/haskell-modules/configuration-ghc-9.0.x.nix
+++ b/pkgs/development/haskell-modules/configuration-ghc-9.0.x.nix
@@ -107,4 +107,8 @@ self: super: {
   # 0.29 introduced support for GHC 9.0.x, stackage has 0.28
   cryptonite = super.cryptonite_0_29;
 
+  # GHC 9.0.x doesn't like `import Spec (main)` in Main.hs
+  # https://github.com/snoyberg/mono-traversable/issues/192
+  mono-traversable = dontCheck super.mono-traversable;
+
 }