testsuite/tests/backpack/should_fail/bkpfail23.stderr


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[1 of 3] Processing p
  [1 of 2] Compiling H[sig]           ( p/H.hsig, nothing )
  [2 of 2] Compiling M                ( p/M.hs, nothing )
[2 of 3] Processing h
  Instantiating h
  [1 of 1] Compiling H                ( h/H.hs, bkpfail23.out/h/H.o )
[3 of 3] Processing r
  Instantiating r
  [1 of 1] Including p[H=h:H]
    Instantiating p[H=h:H]
    [1 of 2] Compiling H[sig]           ( p/H.hsig, bkpfail23.out/p/p-6KeuBvYi0jvLWqVbkSAZMq/H.o )

bkpfail23.bkp:15:9: error:
    • Type constructor ‘F’ has conflicting definitions in the module
      and its hsig file
      Main module: type F :: * -> *
                   type F a = ()
      Hsig file:  type role F phantom
                  type F :: * -> *
                  data F a
      Illegal parameterized type synonym in implementation of abstract data.
      (Try eta reducing your type synonym so that it is nullary.)
    • while checking that h:H implements signature H in p[H=h:H]