Re: Implicit reboxing of unboxed tuple in let-patterns

On Sep 2, 2020, at 9:39 AM, Spiwack, Arnaud wrote:

Ooh… pattern synonyms for unboxed tuple. I must confess that I don't know what the semantics of these ought to be. It does look like an interesting can of worms. How do they currently desugar?

Right now, there is one rule: if the type of any variable bound in the pattern is unlifted, then the pattern is an unlifter-var pattern and is strict. The pattern must be banged, unless the bound variable is not nested. This rule is consistent across all features. This thread is suggesting to add a special case -- one that seems to match intuition, but it's still a special case. And my question is: should the special case be for unboxed tuples? or should the special case be for any pattern whose overall type is unlifted? Richard