# File lib/bundler/definition.rb, line 267
    def index
      @index ||= Index.build do |idx|
        dependency_names = @dependencies.map(&:name)

        sources.all_sources.each do |source|
          source.dependency_names = dependency_names - pinned_spec_names(source)
          idx.add_source source.specs
          dependency_names.concat(source.unmet_deps).uniq!
        end

        double_check_for_index(idx, dependency_names)
      end
    end