code: function printCompilerMsg(msg, file) {
    console.error('%s:%d:%d %s - %s',
                  file || msg.file, msg.lineno + 1,
                  msg.charno + 1, msg.type, msg.error);
    console.error('%s\n%s^',
                  msg.line, Array(msg.charno + 1).join(' '));
  }
docs: Prints a formatted error or warning message.
  @param {CompilerMsg} msg An error or warning message as returned by the
  Closure Compiler Service's JSON output format.
  @param {string|null} file The filename to refer to in error messages. If
  null, then msg.file is used instead.