Specialisation doesn't kick in (RE: Instantiation of overloaded definition *in Core*)

[Erdi, Gergo]

PUBLIC


PUBLIC

Indeed, I am using 9.0.1. I'll try upgrading. Thanks!


From: Simon Peyton Jones <simonpj at microsoft.com>
Sent: Wednesday, October 6, 2021 6:12 PM
To: Erdi, Gergo <Gergo.Erdi at sc.com>
Cc: Montelatici, Raphael Laurent <Raphael.Montelatici at sc.com>; GHC <ghc-devs at haskell.org>
Subject: [External] RE: Specialisation doesn't kick in (RE: Instantiation of overloaded definition *in Core*)

Grego,

Yes I think that should auto-specialise.

Which version of GHC are you using?   Do you have this patch?


commit ef0135934fe32da5b5bb730dbce74262e23e72e8

Author: Simon Peyton Jones simonpj at microsoft.com<mailto:simonpj at microsoft.com>

Date:   Thu Apr 8 22:42:31 2021 +0100



    Make the specialiser handle polymorphic specialisation


Here's why I ask.  The call

$fMonadIO_$c>> = \ (@a) (@b) -> $dm>> @IO $fMonadIO @a @b

indeed applies $dm>> to $fMonadIO, but it also applies it to a and b.  In the version of GHC you have, maybe that stops the call from floating up to the definition site, and being used to specialise it.

Can you make a repro case without your plugin?

Simon

PS: I am leaving Microsoft at the end of November 2021, at which point simonpj at microsoft.com<mailto:simonpj at microsoft.com> will cease to work.  Use simon.peytonjones at gmail.com<mailto:simon.peytonjones at gmail.com> instead.  (For now, it just forwards to simonpj at microsoft.com<mailto:simonpj at microsoft.com>.)

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