[[!comment format=mdwn
 username="joey"
 subject="""comment 1"""
 date="2016-09-20T15:14:19Z"
 content="""
The compiler error message here is not nice; if
[[todo/use_ghc_8.0_custom_compile_errors]] is able to be implemented some
time, I'd hope for a error message more like:

	Couldn't match Property DebianLike with UncheckedProperty UnixLike
	Perhaps you forgot to use `changesFile` or `assume MadeChange`?

Instead of the current mess which has a lot of bloat from type families. 
The meat of the error is here:

	src/Propellor/Property/SiteSpecific/Pebble.hs:29:5:
	    Couldn't match type ‘Propellor.PropAccum.GetMetaTypes
	                           (CombinedType (UncheckedProperty UnixLike) (Property UnixLike))’
	                   with ‘Propellor.Types.Singletons.Sing y0’
	    The type variable ‘y0’ is ambiguous
	    Expected type: Propellor.PropAccum.GetMetaTypes
	                     (CombinedType (UncheckedProperty UnixLike) (Property UnixLike))
	      Actual type: Propellor.Types.MetaTypes.MetaTypes y0

cmdProperty has type UncheckedProperty UnixLike; in order to get
a Property that runs a command, you have to provide some way of checking
if the command made a change to the system.

Since running tar certianly changes the system, adding `assume MadeChange`
after it should do.

Running pip install may not alwways change the system; it's up to you if
you want to do a real check for change there or again `assume MadeChange`.

I think those two changes are all you'll need to get it to compile.
"""]]
