testsuite/tests/typecheck/should_fail/tcfail086.stderr


1
2
3
4
5
6


tcfail086.hs:6:38: error:
    • Can't make a derived instance of ‘Eq Ex’:
        Constructor ‘Ex’ has existential type variables in its type
    • In the data declaration for ‘Ex’
    Suggested fix: Use a standalone deriving declaration instead