[ghc-steering-committee] Proposal #624 on linear let-bindings; recommendation: accept

[Arnaud Spiwack]

On Wed, 24 Jan 2024 at 16:39, Simon Peyton Jones <
simon.peytonjones at gmail.com> wrote:

> Do newtypes make a difference?  E.g      let N x = e in ...
> where N is the data contructor of a newtype?
>

I don't think it has too. So for the moment, I vote to stick to the current
proposal and consider this like all lazy non-variable patterns: must be
unrestricted.

I suspect that there's a possible refinement where we say that a happy
pattern is either:
- A variable
- Strict
- A newtype constructor where the inner pattern is happy.

(then if pat is an unhappy pattern, `let pat` must be unrestricted).

But I don't think I'm quite ready to go there for the time being, and
that'll be a backward compatible change if we change our mind.
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