Issue #7987 has been updated by Nobuyoshi Nakada.

Related to Bug #7993: owner of methods defined after using Module#prepend added

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Bug #7987: Method#parameters should consider a prepended or refined methd
https://bugs.ruby-lang.org/issues/7987#change-46288

* Author: Nobuhiro IMAI
* Status: Closed
* Priority: Normal
* Assignee: 
* Category: core
* Target version: 
* ruby -v: ruby 2.1.0dev (2013-02-28 trunk 39535) [x86_64-linux]
* Backport: 
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In the following example, `Method#parameters` tell the number of argument is one,
but actual methods take two arguments. I got confused..

~~~ruby
 RUBY_DESCRIPTION # => "ruby 2.1.0dev (2013-02-28 trunk 39535) [x86_64-linux]"
 
 module PM
   def m(a, b)
     :pm
   end
 end
 
 class PC
   prepend PM
 
   def m(a)
     :pc
   end
 end
 
 pm = PC.instance_method(:m)
 pm.owner # => #<PC:0x00000001285888>
 pm.parameters # => [[:req, :a]]
 pc = PC.new
 pc.method(:m).owner # => #<PC:0x00000001285888>
 pc.method(:m).parameters # => [[:req, :a]]
 pc.m(:a) # => ArgumentError
 pc.m(:a, :b) # => :pm
 
 class RC
   def m(a)
     :rc
   end
 end
 
 module RM
   refine RC do # !> Refinements are experimental, and the behavior may change in future versions of Ruby!
     def m(a, b)
       :rm
     end
   end
 end
 
 using RM
 
 rm = RC.instance_method(:m)
 rm.owner # => RC
 rm.parameters # => [[:req, :a]]
 rc = RC.new
 rc.method(:m).owner # => RC
 rc.method(:m).parameters # => [[:req, :a]]
 rc.m(:a) # => ArgumentError
 rc.m(:a, :b) # => :rm
~~~




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