From b0d843ccce6dab6205dc58ba79608b6f83fd04ec Mon Sep 17 00:00:00 2001
From: Cyril Cohen <cohen@crans.org>
Date: Thu, 11 May 2017 16:35:54 +0200
Subject: [PATCH] Allow overlapping Arbitrary for Face and System

---
 Connections.hs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Connections.hs b/Connections.hs
index 9673072..8e15172 100644
--- a/Connections.hs
+++ b/Connections.hs
@@ -59,7 +59,7 @@ instance Arbitrary Dir where
 -- Faces of the form: [(i,0),(j,1),(k,0)]
 type Face = Map Name Dir
 
-instance Arbitrary Face where
+instance {-# OVERLAPPING #-} Arbitrary Face where
   arbitrary = fromList <$> arbitrary
 
 showFace :: Face -> String
@@ -443,7 +443,7 @@ border v = mapWithKey (const . face v)
 shape :: System a -> System ()
 shape = border ()
 
-instance (Nominal a, Arbitrary a) => Arbitrary (System a) where
+instance {-# OVERLAPPING #-} (Nominal a, Arbitrary a) => Arbitrary (System a) where
   arbitrary = do
     a <- arbitrary
     border a <$> arbitraryShape (support a)
-- 
2.34.1