[ruby-core:66257] vm_call_cfunc - cfp consistency error

Hi rubyists

It seems I've just encountered a ruby bug. The below code randomly
fails due to "vm_call_cfunc - cfp consistency error.

RSpec.describe do
  context do
    subject { subject }

    it { subject }
  end
end

I also uploaded the whole code and output as a gist.
https://gist.github.com/shouichi/a077b5b903997e16785a

Thanks,
Shouichi

-- 
Shouichi Kamiya