[1 of 2] Processing p
  [1 of 2] Compiling H[sig]           ( p/H.hsig, nothing )
  [2 of 2] Compiling I                ( p/I.hs, nothing )
[2 of 2] Processing q
Module imports and instantiations form a cycle:
        instantiated unit p[H=A]
        imports module ‘A’ (q/A.hsig)
  which imports instantiated unit p[H=A]