diff --git a/src/Data/SumBag.hs b/src/Data/SumBag.hs
index 50226b8fa39a0ac792413b1fa787d672588d9828..12267b5aa001cc786ff8e8244407359a79b87b09 100644
--- a/src/Data/SumBag.hs
+++ b/src/Data/SumBag.hs
@@ -150,7 +150,7 @@ delOnce e = case snd (NE.uncons (multiplicity e)) of
 
 delmin :: Monoid a => Tree a -> (Element a, Tree a)
 delmin Leaf = error "delmin: Empty tree"
-delmin (Node _ e Leaf _) = (e, Leaf)
+delmin (Node _ e Leaf right) = (e, right)
 delmin (Node _ e left right) = (\left' -> balance1 e left' right) <$> delmin left
 
 balanceBound :: Int