I'm trying to figure out why multiple

vararg

parameters are not allowed even if they have different types

vararg

must be the last parameter, so, having 2 of them is not possible as only the latter would really be the last one

well you can have a parameter after it if you use the named argument syntax

Only when calling the function

right, but I am wondering why that is

Because "different types" doesn't mean much. For example:

interface A
interface B
class AI : A
class BI : B
class AB : A, B
fun x(vararg a: A, vararg b: B) { ... }
x(AI(), AB(), BI())

Where is the division line? That's a simple example. It can get far more complicated, and that's even without taking things like generics into account.

sure but couldn't it still be supported for types where it doesn't lead to ambiguity?

Not in a way that wouldn't lead to all sorts of confusion and edge cases.

I see, thanks