From: Jan Wedekind <redmine@...>
Date: 2009-02-10T22:58:53+09:00
Subject: [ruby-core:21953] [Bug #1135] Problem renaming CMath.hypot in Ruby1.9

Bug #1135: Problem renaming CMath.hypot in Ruby1.9
http://redmine.ruby-lang.org/issues/show/1135

Author: Jan Wedekind
Status: Open, Priority: Normal
Category: core, Target version: 1.9.1
ruby -v: ruby 1.9.1p0 (2009-01-30 revision 21907) [x86_64-linux]

# Running the following program with Ruby1.9 ...

require 'complex'
class Module
  def alias_method_chain( target, feature )
    alias_method "#{target}_without_#{feature}", target
    alias_method target, "#{target}_with_#{feature}"
  end
end
Math.module_eval do
  define_method( :hypot_with_test ) do |a,b|
    puts "hypot_with_test( #{a}, #{b} )"
    hypot_without_test( a, b )
  end
  alias_method_chain :hypot, :test
  module_function :hypot_without_test
  module_function :hypot
end
puts Math.hypot( 3, 4 )

# ... results in this error:
# t.rb:14:in `module_function': undefined method `hypot_without_test' for module `CMath' (NameError)
#         from t.rb:14:in `block in <main>'
#         from t.rb:8:in `module_eval'
#         from t.rb:8:in `<main>
#
# Using Ruby 1.8.6 the same program runs without error. The problem also does not occur if 'complex' is not loaded.


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