Implicit reboxing of unboxed tuple in let-patterns

[Iavor Diatchki]

How about the following rule:  unlifted patterns are always strict (i.e.,
you desugar them as if they had an explicit  `!`).   A pattern is
"unlifted" if the type it examines is unlifted.   Seems simple enough and,
I think, it would do what most folks would expect.

I guess a more explicit option would be to make it an error to use a lazy
pattern on an unlifted type, and require programmers to manually add the
`!` but I am not sure that gains much, and is more work in the compiler.

-Iavor

On Thu, Sep 3, 2020 at 10:38 AM Richard Eisenberg <rae at richarde.dev> wrote:

>
>
> On Sep 3, 2020, at 12:10 PM, Spiwack, Arnaud <arnaud.spiwack at tweag.io>
> wrote:
>
> This is all a tad tricky, I must say.
>
>
> ... which is one of the reasons I originally wanted one simple rule. I'm
> not now saying I was in the right, but it is an attractive resting point
> for this discussion.
>
> To be clear, I don't think there's going to be any concrete action here
> without a proposal, so perhaps once this thread finds a resting point
> different than the status quo, someone will have to write it up.
>
> Richard
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