    # File lib/rubygems/commands/dependency_command.rb, line 158
      def find_reverse_dependencies(spec)
        result = []

        Gem.source_index.each do |name, sp|
          sp.dependencies.each do |dep|
            dep = Gem::Dependency.new(*dep) unless Gem::Dependency === dep

            if spec.name == dep.name and
               dep.version_requirements.satisfied_by?(spec.version) then
              result << [sp.full_name, dep]
            end
          end
        end

        result
      end