diff --git a/go/types/mapsets/orderedmap.go b/go/types/mapsets/orderedmap.go
index 1e29236..91b2195 100644
--- a/go/types/mapsets/orderedmap.go
+++ b/go/types/mapsets/orderedmap.go
@@ -80,9 +80,7 @@
 	}
 
 	keys := make([]K, len(s.keys))
-	for i, k := range s.keys {
-		keys[i] = k
-	}
+	copy(keys, s.keys)
 	return keys
 }