Comment by hartator

Awesome work.

    sig {params(person: Person).returns(Integer)}
    def name_length(person)

Not sure if I dig the syntax. Furthermore arguments seems to be the official names for method arguments, not parameters. eg, `ArgumentError`. `params` also feels like it's linked to Rails `params` variable in controllers. It can be confusing.

Something like this will also feel more Rubyist:

    def name_length person: Person, return: Integer

But it probably requires a deeper hack or a change in MRI.