Is it feasible for Exhaustiveness Checks to tell us what we are missing? At least in some cases?

[Tagir Valeev]

IntelliJ IDEA can do this in simple cases (use 'Create missing branches'
action in Alt+Enter menu on "statement does not cover all possible input
values" error message). From what I remember, it could be very non-trivial
to determine a minimal set of missing branches in a general case,
especially if you have generic parameters and nested deconstruction
patterns. I'm not sure but probably it's an NP-complete problem.

With best regards,
Tagir Valeev.

On Tue, Jan 30, 2024 at 6:40 AM David Alayachew <davidalayachew at gmail.com>
wrote:

> Hello Amber Dev Team,
>
> The previous discussions on Checked Exceptions reminded me about this.
>
> Is there any possible future where sealed types will be able to tell you
> which permitted subtypes are missing?
>
> This is actually one of the sleeper features of Checked Exceptions -- they
> don't just give you exhaustiveness, they are even nice enough to tell you
> exactly which Exception type you left out.
>
> This is a godsend for maintenance, fearless refactoring, and general
> correctness.
>
> Any chance we could get this for sealed types in the future?
>
> Thank you for your time and help!
> David Alayachew
>
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