[ruby-core:86953] [Ruby trunk Bug#14744] Refinements modules have a superclass

Issue #14744 has been updated by Eregon (Benoit Daloze).


shugo (Shugo Maeda) wrote:
> The superclass of a refinement module is for implementing super in refined methods.
> However, it may be better to hidden from reflection APIs.

I see, thank you for the explanation.

I'm not sure it's good to hide though, as I noticed this interesting case by seeing code like:


~~~ ruby
module R
  refine Array do
    p instance_method(:sum)
  end
end
~~~

I think either `super` should be implemented differently to not rely on setting a Module's superclass,
or we leave it as it is, and have it visible with reflection APIs since anyway it behaves like there is a "superclass".

FWIW currently in TruffleRuby we do a slightly different lookup when looking for the super method of a refined method, and look at the active refinements to find the super method,
and then use an inline cache to avoid repeated lookups.

----------------------------------------
Bug #14744: Refinements modules have a superclass
https://bugs.ruby-lang.org/issues/14744#change-71918

* Author: Eregon (Benoit Daloze)
* Status: Open
* Priority: Normal
* Assignee: matz (Yukihiro Matsumoto)
* Target version: 
* ruby -v: ruby 2.5.1p57 (2018-03-29 revision 63029) [x86_64-linux]
* Backport: 2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN
----------------------------------------
~~~
$ ruby -e 'module M; refine Array do; p self; p self.class; p ancestors; end; end'
#<refinement:Array@M>
Module
[#<refinement:Array@M>, Array, Enumerable, Object, Kernel, BasicObject]
~~~

So the refinement module (self in the `refine Array do` block) is a Module, but looking at its ancestors it has Array as a "superclass".

Is that expected?
I thought modules can never have a superclass in Ruby.



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