1 files changed, 3 insertions, 0 deletions

diff --git a/haskell/Data/VCDIFF/Types.hsc b/haskell/Data/VCDIFF/Types.hsc
index 015f406..54237b8 100644
--- a/haskell/Data/VCDIFF/Types.hsc
+++ b/haskell/Data/VCDIFF/Types.hsc
@@ -167,6 +167,9 @@ pattern XD3_COMPLEVEL_3     = Flags (#const XD3_COMPLEVEL_3)
 pattern XD3_COMPLEVEL_6     = Flags (#const XD3_COMPLEVEL_6)
 pattern XD3_COMPLEVEL_9     = Flags (#const XD3_COMPLEVEL_9)
 
+instance Semigroup Flags where
+    Flags a <> Flags b = Flags (a .|. b)
+
 instance Monoid Flags where
     mempty = Flags 0
     Flags a `mappend` Flags b = Flags (a .|. b)