Committee,
Proposal #367 suggests using unboxed sums for the results of 7 (seven) primops that use sum types but currently have to encode those explicitly using `Int#`.
The proposal is arguably the right thing, however I'm suggesting we reject it for the following reasons:
- The implementations of the primops would bake in the translation of unboxed sums. Right now our unboxed sum translation is defined in one place - CorePrep - but this proposal would leak it into the implementations of a few primops.
- Migration would entail adding a backwards-compatibility layer, with the associated complexity and risk of performance regressions.
- While the current situation is perhaps inelegant, it's not broken and it's easy to understand.
Thoughts?
Simon