scheduled_task : Confusing error message displayed when using incorrect value with scheduled_task resource

I recently used a scheduled_task resource and coded the trigger section incorrectly like so:

scheduled_task { 'defrag C':

  ensure => present,

  enabled => true,

  command => 'C:\windows\system32\defrag.exe',

  arguments => 'C:',

  trigger   => {

    schedule => 'weekly',

    start_time => '01:00',

    start_time => '01:00',

    day_of_week => 'Sun',

  }

}

The documentation specifies that values of "day_of_week" should be a lowercased string, but when the "Sun" value was used, Puppet emitted the somewhat confusing error message:

Cannot convert "nil" to Fixnum

Can the error message be improved to refer to the incorrect value somehow to make it easier to find the problem and fix it?