[ghc-steering-committee] Proposal: Lazy unboxed tuples / warn on unbanged strict patterns (#35); Recommendation: Reject

[Vitaly Bragilevsky]

Hi,

the lazy unboxed tuples proposal  (
https://github.com/ghc-proposals/ghc-proposals/pull/35) was under
discussion for a long period of time (more than a year and a half since
submission).

As a shepherd to this proposal I recommend rejection based on the following:

* there is no clearly articulated motivation in favor of this proposal
despite complying with the Manual;
* implementing this would lead to hard-to-trace performance issues in the
users code (due to move from strictness in current GHC behaviour to
laziness);
* it looks like the change (B) of the proposal (warn an unbanged strict
patterns) meets no complains, so it is better to be resubmitted as a
separate proposal;
* if resubmitted separately the change (A) should elaborate on desugaring
to make potential performance drawbacks clear;
* it seems (maybe mistakenly) that the author has lost his interest in this
proposal.

Although silence is undestood as agreement, I'd be glad to receive a
feedback on this recommendation.

Regards,
Vitaly
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