I think that you should never try to call static member on instance just because it confuses you. Static members are resolved statically by the class name not by member instance. For example if you have a class A inheriting B and call static function on A, when actual object is B, it will still be called on A.

i haven't its an util class, wanna make builder for static class

in kotlin, builder pattern is not so often used because default parameters (and named parameters) are a much better fit

maybe have some other options to call methods from this class https://github.com/SeleniumHQ/selenium/blob/master/java/client/src/org/openqa/selenium/support/ui/ExpectedConditions.java into my bulder

Maybe I don't understand the problem, but why can't your extension method look like

condition { ExpectedConditions.someMethodFromExpectedConditionsClass }

?

yep u right, just want to make it more DRY. but now i see