Having trouble setting up build with GHC 8.0.1

Hello,

I’ve tried:

machine:
  ghc:
    version: 7.10.3

and:

machine:
  ghc:
    version: 8.0.1

But they both fail with “Action failed: Configure the build”

Example:

https://circleci.com/gh/haskell-works/hw-prim/341