In case this wasn't clear, the context of this discussion in this GHC proposal [1], where David is trying to work around the fact that data types with existential Coercible constraints do not support unpacking. (By "unpacking", I mean putting an {-# UNPACK #-} pragma in front of a field of that type does what you would expect.) An example program which demonstrates the performance issue can be found here [2]. That comment concerns unboxed equality vs. boxed equality, but the same unpacking problems that affect boxed equality also affect Coercible. Ryan S. ----- [1] https://github.com/ghc-proposals/ghc-proposals/pull/116 [2] https://github.com/ghc-proposals/ghc-proposals/pull/116#issuecomment-3823466...
Ah yes thanks.
As I suggest on that thread, I’d really like (someone) to try the “let’s make all evidence strict” idea. I think it could be a perf win all round.
And if so, we’d get what David wants for free.
Simon
From: ghc-devs
participants (2)
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Ryan Scott -
Simon Peyton Jones