Yeah, better documentation is sorely needed in Nix, heck, I can't even look up docstrings in the repl (by default, there is nix-doc[0]. I asked around on IRC about a typechecker for Nix, and people refer me to the Dhall[1] and Nickel[2] projects. Looks like some preliminary work on type checking[3] has been done.
The documentation and language syntax is order of magnitudes better than RPM, though. With RPM, even stuff like commenting out code doesn't work as expected due to parsing quirks and good luck trying to figure out why.