[1 of 3] Processing p
  [1 of 1] Compiling A[sig]           ( p\A.hsig, nothing )
[2 of 3] Processing q
  [1 of 1] Compiling A[sig]           ( q\A.hsig, nothing )
[3 of 3] Processing r
  [1 of 3] Compiling A[sig]           ( r\A.hsig, nothing )

bkpfail47.bkp:10:9: error: [GHC-15843]
    • Type constructor ‘T’ has conflicting definitions in the module
      and its hsig file.
      Main module: type role T representational nominal
                   type T :: * -> * -> *
                   data T a b = MkT
        Hsig file: type role T nominal representational
                   type T :: * -> * -> *
                   data T a b
      The roles are not compatible:
      Main module: [nominal, representational]
        Hsig file: [representational, nominal]
    • while merging the signatures from:
        • p[A=<A>]:A
        • q[A=<A>]:A
        • ...and the local signature for A