diff --git a/src/Renderer/JSON.hs b/src/Renderer/JSON.hs
index 9fb07a163..192a3a499 100644
--- a/src/Renderer/JSON.hs
+++ b/src/Renderer/JSON.hs
@@ -9,7 +9,7 @@ import Renderer
 import Renderer.Split
 
 -- | JSON representing an aligned diff.
-data JSON = JSON { rows :: [Row (SplitDiff (Source Char) Info)] }
+data JSON a = JSON { rows :: [Row (SplitDiff a Info)] }
 
 json :: Renderer a String
 json diff sources = ""