Alternative to isTypeLevPoly

[Csaba Hruska]

I've investigated a bit more. You are right `typeHasFixedRuntimeRep` works
fine, the panic was caused by querying the representation type of
`LitRubbish` type argument. In some cases `getRuntimeRep` causes GHC panic
for `LitRubbish` type arguments.
I did solve the issue with special casing the LitRubbish type argument
handling by using only the `runtimeRepPrimRep` function. In the general
case I tested the type with `isUnboxedTupleType` and `isUnboxedSumType`
which rely on `getRuntimeRep`.
Thanks for the tips and feedback.
Regards,
Csaba

On Wed, Sep 14, 2022 at 6:44 PM Sam Derbyshire <sam.derbyshire at gmail.com>
wrote:

> Hmm, that's strange, both isTypeLevPoly and typeHasFixedRuntimeRep have
> the same precondition: the kind of the type is of the form TYPE rep. So
> they should panic in the same circumstances. Can you give a bit more
> information? What panics are you running into?
>
> On Wed, 14 Sept 2022 at 18:40, Csaba Hruska <csaba.hruska at gmail.com>
> wrote:
>
>> Hi,
>> Thanks for the tip, I've tried it and it behaves differently than
>> isTypeLevPoly. I can get panic when querying the reptype for fixed
>> reptypes. That means isTypeLevPoly semantically is not the same as the
>> negated result of typeHasFixedRuntimeRep.
>>
>> On Wed, 14 Sep 2022, 18:19 Sam Derbyshire, <sam.derbyshire at gmail.com>
>> wrote:
>>
>>> Hi Csaba,
>>>
>>> I think you want the function typeHasFixedRuntimeRep from GHC.Core.Type.
>>>
>>> Best,
>>>
>>> Sam
>>>
>>> On Wed, 14 Sept 2022 at 18:12, Csaba Hruska <csaba.hruska at gmail.com>
>>> wrote:
>>>
>>>> Hello GHC Devs,
>>>>
>>>> I've noticed that the `isTypeLevPoly` function has been removed from
>>>> GHC since 9.4.
>>>> I used it to decide the validity of querying the representation type of
>>>> every value in the STG IR.
>>>> It was mandatory to prevent GHC panics, because there are a lot of
>>>> partial functions in GHC.
>>>> Is there an alternative to `isTypeLevPoly` in GHC 9.4?
>>>>
>>>> Best regards,
>>>> Csaba Hruska
>>>> _______________________________________________
>>>> ghc-devs mailing list
>>>> ghc-devs at haskell.org
>>>> http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
>>>>
>>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.haskell.org/pipermail/ghc-devs/attachments/20220915/8f63c892/attachment.html>