Hey folks, I was playing with Compose over the weekend, and I tried working with the `mutableStateO...

# compose

[segunfamisa]

Hey folks,

I was playing with Compose over the weekend, and I tried working with the mutableStateOf() replacement suggestions for @Model

However, when I use a sealed class hierarchy to model my state, e.g like I've done here (https://github.com/segunfamisa/android-zeitung/pull/17/files#diff-03a45e46e60aaa4e3efa4e4e6041dea3R11-R23), I get an exception during IR lowering. The line that stood out for me was: Caused by: java.lang.AssertionError: Object should have a primary constructor: ...

I'm wondering if this is a technical limitation worth filing as a FR or bug, or something I totally not should be doing?

[Leland Richardson [G]]

Can you narrow this down to a minimal repro case? Also if you can paste the full stacktrace that would be good

[Leland Richardson [G]]

I can’t imagine why this would have anything to do with mutable state or the compose compiler at all but whether its a bug on the kotlin side or compose side we should narrow it down and get it fixed

[mon]

The only oddity I see is the @Composable on the val

[segunfamisa]

The stacktrace is huge, (why I didn't paste it here), but here it is

Untitled

[segunfamisa]

Yeah, I got a different error about referencing a function (I guess the getter of the val) outside a composable function, but I moved the val directly into the function, to confirm that's not where the problem is.

https://kotlinlang.slack.com/archives/CJLTWPH7S/p1593412992211000?thread_ts=1593411552.210300&cid=CJLTWPH7S

[segunfamisa]

I'll try to create a smaller project just with this usecase.

Although this project (https://github.com/segunfamisa/android-zeitung/tree/sf/ir-error-with-kotlin-objects) is already small - this is the only screen in the project and the only screen with compose.

[segunfamisa]

Thanks btw, Mon & Leland.

I was surprised to read Leland's message on a Sunday night 😮😄

[mon]

Oh, stringResource and vectorResource are @Composable functions so calling them in a constructor is probably why

[segunfamisa]

Oh I see. You mean that's why it required me to annotate the val, right?

[segunfamisa]

Hmm, and btw, I just tried to repro this on a simple sample to change text colour and I wasn't able to. It seems to work fine with sealed class objects.

I guess I'm doing something wrong then. Will investigate again later.

Sorry for the false alarm 😄 Probably something wrong with my code.

[Leland Richardson [G]]

ah i didn’t see those composable calls

[Leland Richardson [G]]

that is indeed the problem

[Leland Richardson [G]]

but also, this should be an IDE level error when you try it

[Leland Richardson [G]]

i just refactored our error reporting so i’m actually pretty confident that this would error out correctly in master, but i’ll double check