We need to add role annotations for 7.8

Johan Tibell johan.tibell at gmail.com
Fri Mar 14 13:12:38 UTC 2014

On Fri, Mar 14, 2014 at 2:00 PM, Brandon Allbery <allbery.b at gmail.com>wrote:

> On Fri, Mar 14, 2014 at 5:36 AM, Johan Tibell <johan.tibell at gmail.com>wrote:
>> I'm quite worried about this change though. I thought the default role
>> for data type was nominal, as that's the safe default. If the default is
>> representational, every package author will need to be aware of this
>> feature and update their packages. That's quite a high cost.
> Nominal default breaks everything that uses newtype deriving and doesn't
> have role annotations, doesn't it? Representational default means things
> behave in 7.8 as they did in earlier GHCs.

True, but shouldn't coerce be called unsafeCoerce then as it is, in fact,
unsafe from a correctness perspective?
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