A while ago I was wondering if i had the ability t...

# language-proposals

[groostav]

A while ago I was wondering if i had the ability to disable type inference for particular generic methods. Somebody (I'm sorry I've forgotten) wondered what the use case would be.

intersect is a strange method, and it could be used to mitigate its strangeness.

If you have

val x = listOf(1, 2, 3)
val y = listOf("a", "b", "c")

val c: List<Serializable> = x intersect y

which is legal kotlin code, and compiles.

I think this should pretty clearly be a type error, with the compiler complaining with something like no suitable method found 'intersect' for P1<reciever>: List<Int>, and P2: List<String>"

If kotlin had intersect as a regular extension function instead of an infix fun, with @kotlin.internal.NoInfer on its generic parameter, then the above code would indeed be a compiler failure, but it would be about how you need a type for intersect. This would either force you to select Serializable as your type --if thats actually what you meant, or, more likely, discover your error from a static compile time failure rather than a runtime failure!

Of course, it also makes the code uglier.