In the article from 2010, Tomáš was describing the limitations on WP7:
“The most significant are calls to methods with out or ref parameters.
You also won’t be able to inherit a Ruby class from a CLR class or
implement a CLR interface since that requires us to emit a proper CLR
type. We are going to address both of these limitations in future
Are these two addressed in the latest version of IronRuby for WP7?