Improve interface check by method parameters

[ksss]

Regarding checking interfaces, in addition to checking with #respond_to?, I believe that comparing Method#parameters with types can provide a more accurate interface check.

As an implementation, I've made it so that a match only occurs if the method has exactly the same arguments as the type notation.
Does this match with the philosophy of RBS?
For example, the following code actually works.

# sample.rbs
class Sample
  def foo: (a: Integer, b: String) -> void
end

# sample.rb
class Sample
  def foo(a = {})
    p a # { :a => 1, :b => 'b' }
  end
end

Sample.new.foo(a: 1, b: 'b')

However, for instance, steep would report Ruby::MethodArityMismatch and Ruby::DifferentMethodParameterKind.
What kind of checks should be attempted with RBS alone?

[soutaro]

I think the parameter checking should be permissive. Having an optional argument in implementation while required argument in RBS should be allowed for example.

[soutaro]

Steep validates the method implementation and reports DifferentMethodParameterKind. But I don't think RBS should do it on the implementation side.

[ksss]

Thank you!
I think it seems good to use the criterion "if it can be called, it's OK"

[ksss]

I have reimplemented code to allow for many method call patterns.
I also added an ArgumentChecker to generate arguments from RBS and test whether a method can actually be called.

[soutaro]

Didn't review the implementation very carefully, but give it a try! 💪