PUBLIC
> I'm not surprised that eventually it crashes and burns, because,
> again, I have only declared my DFunId ('$fShowOrderPolicy' in this
> case), but never defined it. Its definition would be a CoreExpr,
> right? So where would I put the pair of '(dfun,
> myCoreExprOfTheRightType)' for GHC to pick it up? Or is it the case
> that GHC would only need an 'Id's definition if it is trying to
> inline/specialize it, i.e. should I just attach the definition to the
> DFunId as an unfolding? Or is 'registerModule' already incomplete and
> it should put the 'CoreProgram' of the module to somewhere deep in the
> GHC state?
I tried adding a reasonable-looking unfolding to the DFun, but I am
still getting the same error when compiling code that uses the instance:
$fShowOrderPolicy [InlPrag=CONLIKE] :: Show OrderPolicy
[LclIdX[DFunId],
Unf=DFun: \ ->
C:Show \ _ [Occ=Dead] -> unpackCStringUtf8# "foo"#
\ _ [Occ=Dead] _ [Occ=Dead] _ [Occ=Dead] -> unpackCStringUtf8#
"bar"#
\ _ [Occ=Dead] _ [Occ=Dead] -> unpackCStringUtf8# "baz"#]
panic! (the 'impossible' happened)
GHC version 9.3.20211130:
lookupIdSubst
$fShowOrderPolicy
InScope {foo mapM_}
Call stack:
CallStack (from HasCallStack):
callStackDoc, called at compiler/GHC/Utils/Panic.hs:181:37 in
ghc-lib-0.20211130-7QA7vLTw0OYJmMsraoHe3v:GHC.Utils.Panic
pprPanic, called at compiler/GHC/Core/Subst.hs:260:17 in
ghc-lib-0.20211130-7QA7vLTw0OYJmMsraoHe3v:GHC.Core.Subst
I have added a minimal working reproducer to
https://gitlab.haskell.org/ghc/ghc/-/issues/21080
So the question remains, where do I need to put the DFun's definition
(a CoreExpr of the right type) for it to be usable as an instance?
Thanks,
Gergo
This email and any attachments are confidential and may also be privileged. If
you are not the intended recipient, please delete all copies and notify the
sender immediately. You may wish to refer to the incorporation details of
Standard Chartered PLC, Standard Chartered Bank and their subsidiaries at
https: //www.sc.com/en/our-locations
Where you have a Financial Markets relationship with Standard Chartered PLC,
Standard Chartered Bank and their subsidiaries (the "Group"), information on
the regulatory standards we adhere to and how it may affect you can be found in
our Regulatory Compliance Statement at https: //www.sc.com/rcs/ and Regulatory
Compliance Disclosures at http: //www.sc.com/rcs/fm
Insofar as this communication is not sent by the Global Research team and
contains any market commentary, the market commentary has been prepared by the
sales and/or trading desk of Standard Chartered Bank or its affiliate. It is
not and does not constitute research material, independent research,
recommendation or financial advice. Any market commentary is for information
purpose only and shall not be relied on for any other purpose and is subject to
the relevant disclaimers available at https:
//www.sc.com/en/regulatory-disclosures/#market-disclaimer.
Insofar as this communication is sent by the Global Research team and contains
any research materials prepared by members of the team, the research material
is for information purpose only and shall not be relied on for any other
purpose, and is subject to the relevant disclaimers available at https:
//research.sc.com/research/api/application/static/terms-and-conditions.
Insofar as this e-mail contains the term sheet for a proposed transaction, by
responding affirmatively to this e-mail, you agree that you have understood the
terms and conditions in the attached term sheet and evaluated the merits and
risks of the transaction. We may at times also request you to sign the term
sheet to acknowledge the same.
Please visit https: //www.sc.com/en/regulatory-disclosures/dodd-frank/ for
important information with respect to derivative products._______________________________________________
ghc-devs mailing list
ghc-devs@haskell.org
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
