When defining more than one method within a class using a proc that returns __method__ all methods will return the symbol representing the last defined method:

DEFINITION = proc { __method__ }

class C
  define_method :one, DEFINITION
  define_method :two, DEFINITION
end

o = C.new

puts o.one  #=> :two (in MRI this returns :one)
puts o.two  #=> :two

Casting DEFINITION into a code block during the method's definition seems to be working correctly though:

class C
  define_method :one, &DEFINITION
  define_method :two, &DEFINITION
end

o = C.new

puts o.one  #=> :one
puts o.two  #=> :two

A lengthier description of the problem can be found at this post in Stack Overflow.