From 9c094d76aeab5f39d874cbf28b00288158c883e8 Mon Sep 17 00:00:00 2001
From: Rob Rix <rob.rix@me.com>
Date: Wed, 20 Dec 2017 17:12:08 -0500
Subject: [PATCH] :memo: FreeVariables.

---
 src/Data/Abstract/FreeVariables.hs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/Data/Abstract/FreeVariables.hs b/src/Data/Abstract/FreeVariables.hs
index 770cc45ff..4412d34e8 100644
--- a/src/Data/Abstract/FreeVariables.hs
+++ b/src/Data/Abstract/FreeVariables.hs
@@ -12,6 +12,7 @@ import Data.Union
 type Name = ByteString
 
 
+-- | Types which can contain unbound variables.
 class FreeVariables term where
   freeVariables :: term -> Set Name