
tcfail118.hs:10:29:
    Overlapping instances for Eq Foo
      arising from the 'deriving' clause of a data type declaration
    Matching instances:
      instance Eq Foo -- Defined at tcfail118.hs:11:25
      instance Eq Foo -- Defined at tcfail118.hs:13:10
    When deriving the instance for (Eq Bar)
