lint error: use of deprecated item 'std::error::Error::description': use the Display impl or to_string()

[rbtcollins]

This is showing up in stable rust now.

use of deprecated item 'std::error::Error::description': use the Display impl or to_string()

I still love error-chain very much; perhaps I shouldn't? Is help needed?

[LukasKalbertodt]

Fixed by #285, but not yet released.

[AndyGauge]

0.12.2 Addresses this issue.