T18851b.hs:27:5: error: [GHC-18872]
    • Couldn't match type ‘A’ with ‘B’
        arising from a functional dependency between constraints:
          ‘C Int B’ arising from a use of ‘f’ at T18851b.hs:27:5
          ‘C Int A’ arising from a use of ‘f’ at T18851b.hs:27:5
    • In the expression: f @A @B
      In an equation for ‘g’: g = f @A @B