Index: trunk/Include/Classes/System/Collections/ArrayList.ab
===================================================================
--- trunk/Include/Classes/System/Collections/ArrayList.ab	(revision 410)
+++ trunk/Include/Classes/System/Collections/ArrayList.ab	(revision 440)
@@ -145,5 +145,5 @@
 	End Sub
 
-	Const Virtual Function BinarySearch(x As Object)
+	Const Virtual Function BinarySearch(x As Object) As Long
 		' TODO: 実装
 	End Function