AccessVariable has no scope method, which breaks define_method, and specifically certain RSpec features

[sarahzrf]

Problem

There is no AccessVariable#scope method. Consequently, the define_method method does not work if passed a method whose @executable is a AccessVariable, because it calls for_define_method, which tries to do @executable.scope. This is specifically an issue for me because RSpec uses define_method to restore the original version of a stubbed method after a test (if the original version is from the object's singleton class), and I'm trying to stub an attr_reader defined in a module's singleton class.

How to Reproduce

class Foo
  attr_reader :bar
end

meth = Foo.instance_method(:bar)
Foo.send(:undef_method, :bar)
Foo.send(:define_method, :bar, meth)

Configuration Details

• Output of rbx -v: rubinius 3.49 (2.3.1 0c24d047 2016-07-22 3.8.0) [x86_64-linux-gnu]
• Output of uname -a: Linux benzrf-laptop 4.6.4-1-ARCH #1 SMP PREEMPT Mon Jul 11 19:12:32 CEST 2016 x86_64 GNU/Linux
• Distribution name (in case of Linux/BSD): Arch
• Contents of config.rb (as a Gist link): If this is part of the Rubinius build process, I'm using Arch's official package. Otherwise, I don't know.
• Contents of configure.log (as a Gist link): Same as for config.rb.

Stack Trace

https://gist.github.com/4d89b32af7ea2f8d423d46677dbcc690