drvfail-foldable-traversable1.hs:9:23: No instance for (Functor Trivial1) arising from the 'deriving' clause of a data type declaration Possible fix: use a standalone 'deriving instance' declaration, so you can specify the instance context yourself When deriving the instance for (Traversable Trivial1) drvfail-foldable-traversable1.hs:13:22: No instance for (Foldable Trivial2) arising from the 'deriving' clause of a data type declaration Possible fix: use a standalone 'deriving instance' declaration, so you can specify the instance context yourself When deriving the instance for (Traversable Trivial2) drvfail-foldable-traversable1.hs:17:22: Can't make a derived instance of ‘Foldable Infinite’: Constructor ‘Infinite’ must not contain function types In the data declaration for ‘Infinite’ drvfail-foldable-traversable1.hs:21:22: Can't make a derived instance of ‘Traversable (Cont r)’: Constructor ‘Cont’ must not contain function types In the data declaration for ‘Cont’