diff --git a/Data/Patch/Internal.hs b/Data/Patch/Internal.hs
--- a/Data/Patch/Internal.hs
+++ b/Data/Patch/Internal.hs
@@ -334,7 +334,7 @@
 
 -- | Resolve a conflict by always using the right-hand side
 theirs :: a -> a -> a
-theirs = const
+theirs = flip const
 
 -- | A convenience version of 'transformWith' which resolves conflicts using 'mappend'.
 transform :: (Eq a, Monoid a) => Patch a -> Patch a -> (Patch a, Patch a)
@@ -343,6 +343,8 @@
 -- | Compute the difference between two documents, using the Wagner-Fischer algorithm. O(mn) time and space.
 --
 -- prop> apply (diff d e) d == e
+--
+-- prop> diff d d == mempty
 --
 -- prop> apply (diff d e) d == apply (inverse (diff e d)) d
 --
diff --git a/patches-vector.cabal b/patches-vector.cabal
--- a/patches-vector.cabal
+++ b/patches-vector.cabal
@@ -2,7 +2,7 @@
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                patches-vector
-version:             0.1.4.3
+version:             0.1.4.4
 synopsis:            Patches (diffs) on vectors: composable, mergeable, and invertible.
 description:         A patch is a collection of modifications (edits) to be made to a sequence of elements. Commonly
                      found in version control systems, patches are also a simple example of a groupoid, supporting (partial) composition