# File lib/rcov.rb, line 108
  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