diff --git a/src/Database/LSMTree/Internal/WriteBufferWriter.hs b/src/Database/LSMTree/Internal/WriteBufferWriter.hs
index 48014706f..c6d858bbd 100644
--- a/src/Database/LSMTree/Internal/WriteBufferWriter.hs
+++ b/src/Database/LSMTree/Internal/WriteBufferWriter.hs
@@ -85,7 +85,7 @@ data WriteBufferWriter m h = WriteBufferWriter
 
 {-# SPECIALISE
   new ::
-      HasFS IO h
+       HasFS IO h
     -> HasBlockIO IO h
     -> WriteBufferFsPaths
     -> IO (WriteBufferWriter IO h)