# File lib/rspec/core/filter_manager.rb, line 123
      def add_location(file_path, line_numbers)
        # locations is a hash of expanded paths to arrays of line
        # numbers to match against. e.g.
        #   { "path/to/file.rb" => [37, 42] }
        locations = @inclusions.delete(:locations) || Hash.new {|h,k| h[k] = []}
        locations[File.expand_path(file_path)].push(*line_numbers)
        @inclusions.replace(:locations => locations)
        @exclusions.clear
      end