Am I not using higher-ordered-functions properly or is Kotlin’s type inference limited? (This is a silly example where I’m trying to get a “flow” or “left compose” operator - I know this is most natural with dot chaining in Kotlin.)

I'm not sure how the associativity works in your case, but I would say the error would make sense if the right-most expression is evaluated first. Try putting

()

around to see if that's the actual issue 😉

Good thinking, but this was not the case. I really wonder how to get this working 🤔

Actually I think

map { it < 2 }

may still be evaluated independently, despite your

()

, so maybe my initial solution was not a solution, but the problem may still be this one

In principle, my code should behave just like ordinary .map, hopefully someone with deeper understanding of type inference catches this :)

I believe type inference is a bit harder for top-level functions like yours compared to functions with receivers like the stdlib's

map

This works fine for me.

@Kroppeb Interesting! That is precisely the code I have. What version of Kotlin and IntelliJ are you running?

I did an update yesterday right before that. So kotlin 1.3.60 and latest intelliJ. But I didn't think the type inference got improved. Does your code compile if you try. Cause if compiling works then it might have been an issue with the ide that got fixed.

Thanks, I’ll have a look.

When I wanted to reuse the scratch file for a different problem I noticed that my ide is now complaining again

🤔 ok so this cannot be relied upon it seems