I realized if I land this in its current 50%+ working state it will not work in JIT since in this form it still has a refinedcallinstr vs using a refinedcallsite. Even had I made that change the JIT would still need some work so I am deferring this until next 9k release.

At the point of pre2 we are passing a substantial portion of refinement tests but we have quite a few significant failing tests (see test/mri). So more work to do before RC

Any progress on this?

I've hit some strange behaviour trying to use refinements with version 9.0.4.0:

module Refinement
  refine Object do
    def new_method
      'new method!'
    end
  end
end

class Thing
  using Refinement

  p in_class_definition: Object.new.new_method

  def test
    p in_method: Object.new.new_method
  end
end

Thing.new.test

outputs

{:in_class_definition=>"new method!"}
NoMethodError: undefined method `new_method' for #<Object:0xcfa9dbf>
   test at test.rb:15
  <top> at test.rb:19

It seems like there's something amiss with the lexical scoping of the method; in MRI, methods defined with the lexical scope where a refinement is activated can make use of that refinement. Is this expected behaviour in JRuby as of 9.0.4.0?

Another related issue: #2977.

I'm going to close this one because refinements are at least in place, albeit rather buggy. #3548 and #2977 track known issues.