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 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, 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 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@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

The type argument to LitRubbish should be a fixed RuntimeRep. If it is not, you can file a bug. I have fixed a related bug in f435d55fe969e7. Krzysztof On Thu, Sep 15, 2022 at 1:12 PM Csaba Hruska wrote:

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 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 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, 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 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@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

_______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

As I see there is no bug at all. I just did not read the description comment for `LitRubbish`. I have misunderstood the meaning of the `Type` argument. According to the comment it is more like `RuntimeRepType` or even `FRRType`. https://github.com/ghc/ghc/blob/master/compiler/GHC/Types/Literal.hs#L134-L1... https://github.com/ghc/ghc/blob/master/compiler/GHC/Core/TyCo/Rep.hs#L116-L1...

LitRubbish Type -- ^ A nonsense value of the given -- representation. See Note [Rubbish literals]. -- -- The Type argument, rr, is of kind RuntimeRep. -- The type of the literal is forall (a:TYPE rr). a

Regards, Csaba On Thu, Sep 15, 2022 at 10:14 PM Simon Peyton Jones < simon.peytonjones@gmail.com> wrote:

The type argument to LitRubbish should be a fixed RuntimeRep. If it is

...

not, you can file a bug

Yes! Please file a bug if you find this.

On Thu, 15 Sept 2022 at 16:36, Krzysztof Gogolewski < krz.gogolewski@gmail.com> wrote:

...

The type argument to LitRubbish should be a fixed RuntimeRep. If it is not, you can file a bug. I have fixed a related bug in f435d55fe969e7.

Krzysztof

On Thu, Sep 15, 2022 at 1:12 PM Csaba Hruska wrote:

...

I've investigated a bit more. You are right `typeHasFixedRuntimeRep`

...

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@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

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,

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

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

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. partial functions in GHC.

...

...

...

...

> Is there an alternative to `isTypeLevPoly` in GHC 9.4? > > Best regards, > Csaba Hruska > _______________________________________________ > ghc-devs mailing list > ghc-devs@haskell.org > http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

_______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

---

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