# File lib/rcov/file_statistics.rb, line 55
    def merge(lines, coverage, counts)
      coverage.each_with_index do |v, idx|
        case @coverage[idx]
        when :inferred 
          @coverage[idx] = v || @coverage[idx]
        when false 
          @coverage[idx] ||= v
        end
      end
      counts.each_with_index{|v, idx| @counts[idx] += v }
      precompute_coverage false
    end