[1 of 2] Processing p
  [1 of 1] Compiling ShouldFail[sig]  ( p/ShouldFail.hsig, nothing )
[2 of 2] Processing q
  Instantiating q
  [1 of 1] Including p[ShouldFail=base-4.13.0.0:Prelude]
    Instantiating p[ShouldFail=base-4.13.0.0:Prelude]
    [1 of 1] Compiling ShouldFail[sig]  ( p/ShouldFail.hsig, bkpfail17.out/p/p-2W6J7O3LvroH97zGxbPEGF/ShouldFail.o )

<no location info>: error:
    • Type constructor ‘Either’ has conflicting definitions in the module
      and its hsig file
      Main module: type Either :: * -> * -> *
                   data Either a b = Left a | Right b
      Hsig file:  type role Either representational phantom phantom
                  type Either :: * -> * -> * -> *
                  data Either a b c = Left a
      The types have different kinds
    • while checking that Prelude implements signature ShouldFail in p[ShouldFail=Prelude]