rubinius

This kind of scenario is common enough in user code that we should assume it will eventually crop up with every core class:

class MyString < String
  # Different initialize signature than String#initialize
  def initialize(foo, baz, zarg = 0)
    super foo
  end
end

This works fine until something comes along and expects the subclass to have the same initialize signature.

This particular one was breaking in String#gsub, trying to create a new "MyString" with self.class.new("something")