Proc#== behaviour.

proc_equality_1.8.7.rb

#
# 1.8.7 docs: http://ruby-doc.org/core-1.8.7/classes/Proc.html#M000463
#
# Return true if prc is the same object as other_proc, or if they are both procs with the same body.
#

RUBY_DESCRIPTION #=> ruby 1.8.7 (2011-02-18 patchlevel 334) [i686-linux]

proc { 1 }     == proc { 1 }      # => false
proc { 1 + 1 } == proc { 1 + 1 }  # => false

proc { |x| x }     == proc { |x| x }      # => false
proc { |x| x.foo } == proc { |x| x.foo }  # => false

lambda { 1 }     == lambda { 1 }      # => false
lambda { 1 + 1 } == lambda { 1 + 1 }  # => false

lambda { |x| x }     == lambda { |x| x }      # => false
lambda { |x| x.foo } == lambda { |x| x.foo }  # => false

Proc.new { 1 }     == Proc.new { 1 }      # => false
Proc.new { 1 + 1 } == Proc.new { 1 + 1 }  # => false

Proc.new { |x| x }     == Proc.new { |x| x }      # => false
Proc.new { |x| x.foo } == Proc.new { |x| x.foo }  # => false

proc_equality_1.9.2.rb

#
# 1.9.2 docs: http://ruby-doc.org/core/classes/Proc.html#M000554
#
# Return true if prc is the same object as other_proc, or if they are both procs with the same body.
#

RUBY_DESCRIPTION #=> ruby 1.9.2p180 (2011-02-18 revision 30909) [i686-linux]

proc { 1 }     == proc { 1 }      # => true
proc { 1 + 1 } == proc { 1 + 1 }  # => false

proc { |x| x }     == proc { |x| x }      # => true
proc { |x| x.foo } == proc { |x| x.foo }  # => false

lambda { 1 }     == lambda { 1 }      # => true
lambda { 1 + 1 } == lambda { 1 + 1 }  # => false

lambda { |x| x }     == lambda { |x| x }      # => true
lambda { |x| x.foo } == lambda { |x| x.foo }  # => false

Proc.new { 1 }     == Proc.new { 1 }      # => true
Proc.new { 1 + 1 } == Proc.new { 1 + 1 }  # => false

Proc.new { |x| x }     == Proc.new { |x| x }      # => true
Proc.new { |x| x.foo } == Proc.new { |x| x.foo }  # => false