1 files changed, 6 insertions, 0 deletions

diff --git a/src/Network/BitTorrent/DHT/ContactInfo.hs b/src/Network/BitTorrent/DHT/ContactInfo.hs
index dfc93ed7..ed38caf7 100644
--- a/src/Network/BitTorrent/DHT/ContactInfo.hs
+++ b/src/Network/BitTorrent/DHT/ContactInfo.hs
@@ -15,6 +15,7 @@ import Data.List as L
 import Data.Maybe
 import Data.HashMap.Strict as HM
 import Data.Serialize
+import Data.Semigroup
 import Data.Wrapper.PSQ as PSQ
 import Data.Time.Clock.POSIX
 import Data.ByteString (ByteString)
@@ -190,6 +191,11 @@ instance Default (PeerStore) where
   def = PeerStore HM.empty
   {-# INLINE def #-}
 
+instance Semigroup PeerStore where
+  PeerStore a <> PeerStore b =
+    PeerStore (HM.unionWith swarmInsert a b)
+  {-# INLINE (<>) #-}
+
 -- | Monoid under union operation.
 instance Monoid PeerStore where
   mempty  = def