James C. Davis

So this command would add the appropriate stuff to `paths` and `include`? It could also check that `isDevelopingAddon() === true`, but probably shouldn't modify the addon automatically?

I hit this last week in an engine for work where, being new to the codebase, I didn't realize `allowJs: true` was set and it didn't bite me until publish...

I did some playing around with this over the holiday break. It seems to be related to the conditional types in `UnwrapComputedPropertyGetter`. It does *not* seem to be the `infer`...

We [worked around this](https://github.com/CenterForOpenScience/ember-osf-web/blob/06da0cc22ed83ed078dd102bdbc74457be0b6c9c/types/ember-osf-web/index.d.ts#L5) in `ember-osf-web` (as @mogstad mentioned, but also including `Copyable`).

3.1 definitely made it much worse: ``` $ npm install typescript@~3.1 + [email protected] $ time npx tsc real 7m53.560s ``` but all those times above were with TS **2.8**!

Ok, this is bizarre! Apparently, order matters. I'll explain. For https://github.com/mogstad/typescript-ember-slow-example Using tsc 3.2.4, I get: ``` $ time npx tsc real 9m57.583s ``` If I go into `node_modules/@types/ember__object/observable.d.ts` and...

I've created a [minimal repro](https://github.com/jamescdavis/typescript-promise-all-slow-repro). I found the same as @chriskrycho: major performance regression in 3.1-3.3 that appears to be fixed in 3.4, but there are other issues with conditional...

I'm hoping to look at this week as well. And I'm pretty familiar with traits. :wink:

@calvin-fb any ideas on a proper fix?

@matthew-robertson tagging you as well