# File lib/rspec/core.rb, line 109
  def self.const_missing(name)
    case name
      when :Matchers
        # Load rspec-expectations when RSpec::Matchers is referenced. This allows
        # people to define custom matchers (using `RSpec::Matchers.define`) before
        # rspec-core has loaded rspec-expectations (since it delays the loading of
        # it to allow users to configure a different assertion/expectation
        # framework). `autoload` can't be used since it works with ruby's built-in
        # require (e.g. for files that are available relative to a load path dir),
        # but not with rubygems' extended require.
        require 'rspec/expectations'
        ::RSpec::Matchers
      else super
    end
  end