From 63978a11cc1a512e564237e83060e9aa29ebce73 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9s=20Sicard-Ram=C3=ADrez?= <asr@eafit.edu.co>
Date: Sun, 7 Jan 2018 23:52:32 -0500
Subject: [PATCH] Added Semigroup instance.

The instance was required by GHC 8.4.1-alpha1.
---
 src/Control/Monad/Plus.hs | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/Control/Monad/Plus.hs b/src/Control/Monad/Plus.hs
index 25f4782..654d133 100644
--- a/src/Control/Monad/Plus.hs
+++ b/src/Control/Monad/Plus.hs
@@ -1,5 +1,5 @@

-{-# LANGUAGE DeriveFunctor, DeriveFoldable, GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE CPP, DeriveFunctor, DeriveFoldable, GeneralizedNewtypeDeriving #-}

 -------------------------------------------------------------------------------------
 -- |
@@ -263,6 +263,9 @@ instance Category Partial where

 instance Monoid (Partial a b) where
     mempty  = mzero
+#if !MIN_VERSION_base(4,11,0)
     mappend = mplus
-
-
+#else
+instance Semigroup (Partial a b) where
+  (<>) = mappend
+#endif