How are extension functions handled when two of them are valid? As an example, I'm thinking of adding

Any?.filter

,

Any?.map

etc extension functions, to help with null handling. How would the compiler react if it is used in a file in which

List.filter

(from the standard lib) is called? More precisely, if I write the following, which extension function would be called (assuming both are imported):

val l = listOf (...)
l.filter { it... }

In that case they are both valid choices by the compiler, since

List

is also a

Any?

. So, which one is called?

Test it? But personally, I hope.the compiler let's you know you have ambiguous definitions. I'd be surprised if it doesn't.