Hi Mike Repro case is something like * Here is a source or files * Compile like this * Look at the generated Core...observe silly thing happening Evidence of importance could be as simple as "in my application I'm seeing a lot of these redundant dictionaries being built for no reason". Or, stronger "this is slowing my application down by 5%". TL;DR: is this just a curiosity that you noticed, or is it something that matters to you, and if so why? | Is there any way to see how far evaluates the dictionary construction to be | able to match on that unboxed tuple? Not sure what you mean here, but once we have a repro case we can discuss. Worth opening a ticket too -- email is easily lost. Thanks Simon | -----Original Message----- | From: Michael Sperber <sperber@deinprogramm.de> | Sent: 12 August 2021 10:15 | To: Simon Peyton Jones <simonpj@microsoft.com> | Cc: Sebastian Graf <sgraf1337@gmail.com>; glasgow-haskell-users@haskell.org | Subject: Re: Avoiding construction of dead dictionaries | | | On Mon, Aug 09 2021, Simon Peyton Jones <simonpj@microsoft.com> wrote: | | > Could you offer a small repro case, with a pointer to evidence that it | matters in practice, and open a ticket? | | I'll try my best, but I'm unsure how I would generate evidence. Could you | give me a hint? | | Is there any way to see how far evaluates the dictionary construction to be | able to match on that unboxed tuple? | | -- | Regards, | Mike