[Checkers] Suggestions for NonNull checker warning messages

[Matt Papi]

>  I believe that this message is a result for double checking.  NonNull
> Checker checks for de-referencing null, and the framework checks for method
> invocation on null references.

Actually it doesn't double check; see the implementation of NonNullVisitor.

>  Actually, you can simply override BaseTypeVisitor.checkMethodInvokability()
> to always return true to avoid the double checking.

That's precisely my issue: I want the framework to check method
invokability for @Raw but not for @NonNull. I guess I could have it
return true only if the method's receiver is NonNull, but that seems
like a hack to me.



>  Do it have something to do with @NonNull not doing anything with binary
> trees?

As Mike mentioned, the problem doesn't seem to be related to String
concatenation.


- Matt