Not sure if that is a serious question, but it’s because formatting doesn’t depend on the type of variables but going to the definition of a field obviously depends on the type that the field is in.

formatting does depend on the type of variables. Go look at ktfmt's codebase and come back after you've done so...

Maybe my example was not clear enough for you - I guess it’s possible you’ve never experienced working intellisense, so you don’t understand the feature I’m describing.

Lol, nice try with the insult there. I code in Kotlin, my intellisense works just fine. I just think you're quite ignorant and have no clue what you're actually talking about.

Ctrl-click on bar. Where does it jump to?

it gives you an option, just like if it was an interface. Did you actually try this out before commenting? Guessing not. And how often are you naming functions the exact same thing across two different classes without using an interface? And if you were using an interface intellisense would work the exact same way, giving you the option to jump to any of the implementations.

I'm sorry, but you clearly haven't thought this out, or you're really quite ignorant as to how intellisense works in all languages (including Ruby, and including statically typed languages).