Bug #16977: Ambiguous lookup super for refinements

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 2.6.3p62 (2019-04-16 revision 67580)
• Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN

[ssnickolay (Nikolay Sverchkov)]

In specification we have the note

Note that super in a method of a refinement invokes the method in the refined class even if there is another refinement which has been activated in the same context.

If we take a look at the example:

module A
  def foo
    "foo from A"
  end
end

class C
  def foo
    "foo from C"
  end
end

refinement =
  Module.new do
    refine C do
      include A
    end
  end

refinement2 =
  Module.new do
    refine C do
      def foo
        super
      end
    end
  end

using refinement
using refinement2

puts C.new.foo

# => "foo from C"

This works as described in the specification.

However, if we replace refinement2 in the example with

# the same A, C and refinement definitions here

module B
  def foo
    super
  end
end

refinement2 =
  Module.new do
    refine C do
      include B
    end
  end

using refinement
using refinement2

puts C.new.foo

# => "foo from A"

I don’t understand why include works differently than refining a method directly.
From my point of view, we should get foo from C in both cases.

[shugo (Shugo Maeda)]

ssnickolay (Nikolay Sverchkov) wrote:

In specification we have the note

Note that super in a method of a refinement invokes the method in the refined class even if there is another refinement which has been activated in the same context.

If we take a look at the example:
(snip)
I don’t understand why include works differently than refining a method directly.
From my point of view, we should get foo from C in both cases.

In the former case, super is called in the scope where a refinement is defined, and thus it invokes the method in the refined class.
However, in the latter case, super is called outside the scope where a refinement is defined, and it looks up the ancestor chain.

The behavior of include in refine blocks is confusing, so it may be prohibited in the future.

[Eregon (Benoit Daloze)]

• Related to Bug #17007: SystemStackError when using super inside Module included and lexically inside refinement added

• Status changed from Open to Closed

Applied in changeset git|021cec938af55a7ef368eadc99a6e3ff2252510e.

---

Clarify behavior of super in method in module included in refinement [ci skip]

Fixes [Bug #16977]