From 11ca296fc09af31871fd2b3867831478bc74c306 Mon Sep 17 00:00:00 2001
From: Timothy Clem <timothy.clem@gmail.com>
Date: Mon, 27 Nov 2017 14:41:13 -0800
Subject: [PATCH] Add FreeVariables1 instance for []

---
 src/Abstract/FreeVariables.hs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/Abstract/FreeVariables.hs b/src/Abstract/FreeVariables.hs
index cd84db2a4..b162a8d7a 100644
--- a/src/Abstract/FreeVariables.hs
+++ b/src/Abstract/FreeVariables.hs
@@ -26,3 +26,5 @@ instance (FreeVariables1 syntax) => FreeVariables1 (TermF syntax ann) where
 
 instance (Apply FreeVariables1 fs) => FreeVariables1 (Union fs) where
   liftFreeVariables f = apply (Proxy :: Proxy FreeVariables1) (liftFreeVariables f)
+
+instance FreeVariables1 []