# File lib/bundler/vendor/molinillo/lib/molinillo/dependency_graph.rb, line 151
    def add_edge(origin, destination, requirement)
      if origin == destination || destination.path_to?(origin)
        raise CircularDependencyError.new([origin, destination])
      end
      Edge.new(origin, destination, [requirement]).tap { |e| edges << e }
    end