diff --git a/theories/spanning_tree/mon.v b/theories/spanning_tree/mon.v
index fd68ebcdde227f551c987dd10db806861798acc1..615df852b7816cb64c4ece73b341d7dc7626dd48 100644
--- a/theories/spanning_tree/mon.v
+++ b/theories/spanning_tree/mon.v
@@ -70,7 +70,7 @@ Definition Gmon := gmapR loc (exclR chlO).
 Definition excl_chlC_chl (ch : exclR chlO) : option (option loc * option loc) :=
   match ch with
   | Excl w => Some w
-  | ExclBot => None
+  | ExclInvalid => None
   end.
 
 Definition Gmon_graph (G : Gmon) : graph loc := omap excl_chlC_chl G.