assert_equal 'ok', %q{
  module M
    class A
      class << self
        attr_accessor :at
        def workflow_rule
          yield self
        end

        def eval_str(str)
          eval(str)
        end
      end
    end
  end
  begin
    M::A.eval_str(<<-END)
    workflow_rule do |r|
      r.at 1
    end
    END
  rescue ArgumentError => e
    print "ok"
  end
}, '[ruby-core:14641]'

assert_equal %{ok}, %{
  class A
    attr :m
  end
  begin
    A.new.m(3)
  rescue ArgumentError => e
    print "ok"
  end
}, '[ruby-core:15120]'