# File lib/facets/core/kernel/warn_with_line.rb, line 13
  def warn_with_line(msg="", fulltrace=nil)
    trace = caller(1)
    where = trace[0].sub(/:in.*/,'')
    STDERR.puts "#{where}: Warning: #{msg}"
    STDERR.puts trace.map { |t| "\tfrom #{t}" } if fulltrace
  end