[[!comment format=mdwn username="spwhitton" subject="comment 3" date="2015-12-06T23:58:51Z" content=""" I've implemented these in the `safetychecks` branch of `https://git.spwhitton.name/propellor`. A nice side effect of my implementation is that the spin only errors out after there's been an attempt to compile Propellor. So you can run `propellor --spin` in order to have GHC typecheck your code on a feature branch. """]]