Hi Sean,
On Mon, Nov 19, 2012 at 2:18 PM, Sean Leather
We discovered that GHC and GHCi (7.4.1) accept promoted types without specifying language extensions (and even when specifying -XHaskell98).
For example, promoted lists are accepted:
Prelude> type T = [Int,Char] Prelude> :i T type T = (:) * Int ((:) * Char ([] *)) -- Defined at <interactive>:2:6
This is rejected in 7.6.1: <interactive>:2:10: Illegal type: '[Int, Char] Perhaps you intended to use -XDataKinds
Also, promoted datatypes:
data N = Z type T = 'Z
This isn't rejected, but I guess it should, indeed. Thanks, Pedro
I'm guessing you can't use these types anywhere (since they are not kind *), so they won't be very useful, but it seems like this should be disallowed.
Regards, Sean
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