Re: apparently only with extension methods nil != System::Object

I’ve done some more investigation and it appears that it has to do with
Extension methods.

public static bool IsNull(this object value)
return value == null;


public static bool IsNull2(object value)
return value == null;

System::Web::Mvc::IronRuby::Extensions::ObjectExtensions.is_null nil
:0: can’t convert NilClass into Object (TypeError)

System::Web::Mvc::IronRuby::Extensions::ObjectExtensions.is_null2 nil
=> true

I’ve commented the issue on codeplex but couldn’t change the title of

Author of IronRuby in Action (

Andy Warhol

  • “I am a deeply superficial person.”