Expression is never null with !!, but can be null

[torch2424]

Hello!

So I found this super small, low priority bug. Where !! can be used to force a variable to not be null to skip null checking, however, the compiler says the expression cannot be null, but will crash if it is. So maybe it's just a better error message? 🤔

Assigning to myself cause I could totally figure this out, once I get the time 😄

Sandbox Demo Link

[dcodeIO]

I think what happens there is that stringOrNull()! is treated as if the user knows better than the compiler, that this is indeed never null. The compiler then inserts a runtime check there as a guarantee, the one producing the "unexpected null" runtime error because the user was wrong, and changes the type to non-nullable. Now, the second ! operates on a non-nullable type, leading to the info message that the type is never null.

[MaxGraey]

I think double !! should behave the same as single ! in this context due to first exclamation postfix operator convert to non-nullable and second should just ignored skipped for non-nullable types

[torch2424]

@dcodeIO @MaxGraey Ah! Thank you for the insight! 😄

And yeah I am in agreement with @MaxGraey , if we feel postfix !! is the developer saying I know what I'm doing, I can open a PR to ignore if the character before is another !? 😄

[dcodeIO]

Wondering a bit why one would write !!, but I also don't see a risk in suppressing the info message as long as the second ! will not result in another runtime check. Not sure if that's currently the case, but also shouldn't be too hard to change if currently the case.