Reporting a minor pain point I had when working with Sealed Types recently

[David Alayachew]

Hello Amber Dev Team,

I have been making extremely frequent use of sealed types and records to
model Abstract Data Types, but the lack of local sealed types is becoming
more and more of an annoyance to me.

Annoyance is the correct word -- the cost I pay is in wasting time
refactoring things. On rare occasions, I will refactor incorrectly and have
to spend about 15-30 minutes reteaching myself what each one meant. This is
certainly not an expensive cost. But this past week, I hit this problem
multiple times back to back, such that the sum total was a few hours of
refactoring across a full week of work. Because of that, this email felt
warranted.

To very quickly explain my situation, I have a bunch of projects I'm
working on, each of which does a lot of work deserializing semi-structured
outside data. So, an ideal use case for ADT's. I keep running into the same
bar over and over again -- a project has many different types of data it
needs to deserialize (>20 different data types), and several of those data
types are quite similar to each other, such that the names end up being
similar. When I go to refactor a class - either splitting it up or
combining multiple classes into a single one, I usually end up either
mixing up sealed types (using the incorrect one) or combining parent
classes that both have private sealed types with the same name.

This week was notable because almost all of my projects that I am working
on ran into this same problem at around the same time.

It's not a very big issue, but out of the 60+ hours I worked this week, I'd
say about 3-4 of those hours were spent debugging and wasting time on
fixing refactoring bugs. Admittedly, that's probably the worst-case
scenario one can get for this problem, which shows that the scale of damage
isn't very large. Also, I am pretty sure I know the reasons why it hasn't
been done yet, and I don't contest them. However, I do want to share my
experience in case that information influences any decision-making on the
matter.

Thank you for your time!
David Alayachew
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