class X
class Y
instance i :: X
instance i :: Y
{-
at src/Main.purs line 109, column 1 - line 109, column 15
  Instance i has been defined multiple times:
    src/Main.purs line 109, column 1 - line 109, column 15

in type class instance
  Main.Y
-}

class C
class C
{-
in module Main
  Type class C has been defined multiple times:
    src/Main.purs line 107, column 1 - line 107, column 7
-}