From 0d2e88140580041bbdbf9fedf5e09c2542ca0677 Mon Sep 17 00:00:00 2001
From: Rob Rix <rob.rix@github.com>
Date: Mon, 30 Nov 2015 16:21:41 -0500
Subject: [PATCH] Diffing an empty list against a non-empty list produces
 insertions.

---
 src/SES.hs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/SES.hs b/src/SES.hs
index b2770fe73..ef7a86a80 100644
--- a/src/SES.hs
+++ b/src/SES.hs
@@ -26,4 +26,5 @@ ses diffTerms cost (a : as) (b : bs) = case diffTerms a b of
 
 diffAt :: (Integer, Integer) -> [Term String Info] -> [Term String Info] -> State (Map.Map (Integer, Integer) [(Diff String Info, Integer)]) [Diff String Info]
 diffAt _ [] [] = return []
+diffAt (i, j) [] bs = return $ (Pure . Insert) <$> bs
 diffAt (i, j) as bs = _