diff --git a/AlgebraicDataflowArchitectureModel/models/PathParamBug.model b/AlgebraicDataflowArchitectureModel/models/PathParamBug.model
index 3a27bfa..de8c7b5 100644
--- a/AlgebraicDataflowArchitectureModel/models/PathParamBug.model
+++ b/AlgebraicDataflowArchitectureModel/models/PathParamBug.model
@@ -2,7 +2,7 @@
 	out accounts(acs: Map, signUp(id, name)) = insert(acs, id, {"name": name, "friends": nil})
 }
 
-channel makeFriend(aid) {
-	out accounts.{aid}.friends(friends: List, addFreinds(fid)) = append(friends, fid)
-	out accounts.{fid}.friends(friends: List, addFreinds(fid)) = append(friends, aid)
+channel makeFriend(aid: Str) {
+	out accounts.{aid}.friends(friends: List, addFreinds(fid: Str)) = append(friends, fid)
+	out accounts.{fid}.friends(friends: List, addFreinds(fid: Str)) = append(friends, aid)
 }
\ No newline at end of file
diff --git a/AlgebraicDataflowArchitectureModel/src/simulator/Event.java b/AlgebraicDataflowArchitectureModel/src/simulator/Event.java
index c841b23..17fd474 100644
--- a/AlgebraicDataflowArchitectureModel/src/simulator/Event.java
+++ b/AlgebraicDataflowArchitectureModel/src/simulator/Event.java
@@ -69,7 +69,7 @@
 				}
 				if (ancestor!= null) {
 					channelSelectorAndValues.add(new AbstractMap.SimpleEntry<>(sel, ancestor.getParameter()));
-					selectorVariables.put(new Variable(sel.getExpression().toString()), ancestor.getParameter());
+					selectorVariables.put((Variable)sel.getExpression(), ancestor.getParameter());
 				}
 			}
 		}