testsuite/tests/deriving/should_fail/T9600.stderr


1
2
3
4
5
6


T9600.hs:4:39: error:
    • Can't make a derived instance of ‘Applicative Foo’:
        ‘Applicative’ is not a stock derivable class (Eq, Show, etc.)
        Try GeneralizedNewtypeDeriving for GHC's newtype-deriving extension
    • In the newtype declaration for ‘Foo’