T13929.hs:29:27: error:
    A representation-polymorphic type is not allowed here:
      Type: GUnboxed f rf
      Kind: TYPE rf
    In the type of expression: gunbox x

T13929.hs:29:37: error:
    A representation-polymorphic type is not allowed here:
      Type: GUnboxed g rg
      Kind: TYPE rg
    In the type of expression: gunbox y

T13929.hs:33:24:
    A representation-polymorphic type is not allowed here:
      Type: GUnboxed f rf
      Kind: TYPE rf
    In the type of expression: gunbox l

T13929.hs:34:26:
    A representation-polymorphic type is not allowed here:
      Type: GUnboxed g rg
      Kind: TYPE rg
    In the type of expression: gunbox r