testsuite/tests/backpack/should_fail/bkpfail46.stderr


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[1 of 3] Processing p
  [1 of 2] Compiling A[sig]           ( p/A.hsig, nothing )
  [2 of 2] Compiling M                ( p/M.hs, nothing )
[2 of 3] Processing q
  Instantiating q
  [1 of 1] Compiling A                ( q/A.hs, bkpfail46.out/q/A.o )
[3 of 3] Processing r
  Instantiating r
  [1 of 1] Including p[A=q:A]
    Instantiating p[A=q:A]
    [1 of 2] Compiling A[sig]           ( p/A.hsig, bkpfail46.out/p/p-HVmFlcYSefiK5n1aDP1v7x/A.o )

bkpfail46.bkp:15:9: error:
    • Type constructor ‘K’ has conflicting definitions in the module
      and its hsig file
      Main module: type K :: * -> Constraint
                   type K a = GHC.Classes.Eq a :: Constraint
      Hsig file:  type K :: * -> Constraint
                  class K a
      Illegal parameterized type synonym in implementation of abstract data.
      (Try eta reducing your type synonym so that it is nullary.)
    • while checking that q:A implements signature A in p[A=q:A]