Write extends @NonNull Object instead of extends Object.

[cpovirk]

The simpler formulation doesn't work in stub files, even in JDK stubs.
(This is typetools bug number 3030.)

I tested against a file with the call:

java.util.List.of("", null);

[wmdietl]

Thanks for making this suggestion!

At first I was confused, b/c typetools 3030 sounds like using "T extends Object" in the annotated JDK works as expected. Then I remembered that nowadays this JDK is in the end loaded as stub files in the Checker Framework.

I didn't see any documentation that issue 3030 is the intended behavior and I would like to avoid having to explicitly write the NonNull bounds - which is particularly confusing here, as the source and stub file behavior is different.

So I tried fixing 3030 in eisop/checker-framework#247
If that fix works, I would prefer closing this PR without merging.

I also tested the List.of example with 247 and do get the expected error.

@cpovirk Please let me know in 247 if you see anything odd or if there is some documentation in the manual that should be updated.

[wmdietl]

I've merged eisop/checker-framework#247.
Please close this PR or report any remaining issues.

[cpovirk]

Thanks! I can't think of anything to document or anything else to do. I'll let you know if this finds anything fun when we upgrade to the June release :)

[cpovirk]

Update: The combination of eisop/checker-framework#247 and #16 is definitely turning some things up :)

[wmdietl]

@cpovirk "turning things up" in a good way or that we should re-open this PR?

[cpovirk]

Oh, sorry :) In a good way -- catching declarations that would have permitted NPEs.