From: Alex N <masterlambaster@...>
Date: 2012-02-14T20:23:14+09:00
Subject: [ruby-core:42612] [ruby-trunk - Bug #6020] Unexpected is_a/kind_of behaviour


Issue #6020 has been updated by Alex N.


=begin
Yes, i know how instance is_a? works. The problem is that the module owns the same functionality as well.
For example:
 module A; end
 A.class #=> Module
 A.is_a?(A) #=> false
 A.is_a?(A.class) #=> true

From implementation perspective it's totally ok: Module is not A.
But (({A.ancestors})) is (({[A]})), meanwhile (({Module.ancestors})) it the whole set of the core objects. At the same time module A is an BasicObject.
I'm not saying that it's completely wrong, but it feels confusing. On the other had it's really really edge case.
=end

----------------------------------------
Bug #6020: Unexpected is_a/kind_of behaviour
https://bugs.ruby-lang.org/issues/6020

Author: Alex N
Status: Feedback
Priority: Low
Assignee: 
Category: core
Target version: 
ruby -v: ruby 2.0.0dev (2012-02-14 trunk 34598) [x86_64-darwin11.3.0]


=begin
I've noticed some inconsistent is_a?/kind_of? methods behavior in a very special cases
 self.class #=> Object

 BasicObject.is_a?(BasicObject) #=> true
 Module.is_a?(Module) #=> true
 Class.is_a?(Class) #=> true
 Object.is_a?(Object) #=> true

 BasicObject.is_a?(Module) #=> true

 Integer.is_a?(Integer) #=> false
 class A; end
 A.is_a?(A) #=> false
 
 module B; end
 B.is_a?(B) #=> false

 class C < Object; end
 C.is_a?(C) #=> false
 C.is_a?(Object) #=> true
 C.is_a?(BasicObject) #=> true
 C.is_a?(Module) #=> true
 C.is_a?(Class) #=> true

 c = C.new
 c.is_a?(Module) #=> false
 c.is_a?(Class) #=> false

It looks like it's because Class, Module, Object and BasicObject have class Class, superclass is set properly. 
Anyway all is logical but not expected. 
=end




-- 
http://bugs.ruby-lang.org/