Artisan error doesn't show line number

I'm writing a console command for my Laravel 5.1 app. While developing, I'm having an error somewhere. When artisan reports the error, it doesn't give me the line number or file; I just get an error in the shell highlighted in red background:

  [ErrorException]
  Undefined variable: answerer

How do I get artisan to show me more information about where the error occurred, specifically line number and file?

via Chebli Mohamed