@typescript-bot test this

Edit: this seems to be restricted to members only?

@ajafff Indeed - it is limited to repo owners and MS org members right now (it holds up a lot (1 of our 5 containers for around half an hour) of resources to run them and we don't want them triggered frivolously). @RyanCavanaugh I imagine you want to monitor the result, since you suggested it.

@typescript-bot test this

Heya @weswigham, I've started to run the extended test suite on this PR at 0482b61. You can monitor the build here. It should now contribute to this PR's status checks.

So this introduces errors into 10 of our RWC projects, with little added value - the setter-only objects mostly look like they're clearly written to actually be setter only - mostly membranes that do a little extra work on write. TBH, I personally have no problem with most of the usages in our RWC suite - they make a good argument for properly recognizing writeonly props.

Sounds like this needs to block on #21759 then?

I'd say so, yeah. I don't think we can make it an error reasonably when people can't yet express the state in which a setter-only property is correct (and I think we'd still need a flag to opt-out of the new error - some projects like vscode seem to use setter-only stuff heavily and all those types probably won't get updated to writeonly at once).

Closing because this can't be merged unless #21759 happens (which is quite unlikely in the near future)