diff --git a/sources/zweic/Analyzer.scala b/sources/zweic/Analyzer.scala
index 0581029..a9a3f76 100755
--- a/sources/zweic/Analyzer.scala
+++ b/sources/zweic/Analyzer.scala
@@ -88,7 +88,11 @@
 			ownerClass.lookupMethod(name.name) match {
 				case Some(m) =>
 					//TODO: check that old returntype is subtype of new returntype and args are subtypes of old args
-					checkSubtype(tree.pos, "redefinition of class method '"+name+"' has incompatible returntype", rt, m.restype);
+					checkSubtype(tree.pos, "redefinition of class method '" + name + "' has incompatible returntype", rt, m.restype);
+
+					if (paramtypes.length != m.paramtypes.length) {
+						Report.error(tree.pos, "wrong number of arguments for class method '" + name +  "' redefinition");
+					}
 
 					if ( !m.paramtypes.zip(paramtypes).forall(x:Pair[Type,Type] => x._1.isSubtype(x._2)) ) {
 						Report.error(tree.pos, "incompatible argument types for class method redefinition: \n	required: " + paramtypes.foldLeft("")((a,b)=>a + " " + b) +