Is there any way to "pin" generics to another type...

# general-advice

[Caleb B]

Is there any way to "pin" generics to another type? Like have a Map<Class<T>, Supplier<T>>, where T is NOT a type parameter of the enclosing class but instead "pinning" the type of the supplier to the type of the class for runtime type validation? Instead of Map<Class<*>, Supplier<*>> and having to suppress constant type coercion warnings

[Sam]

I think a typealias would do the trick:

typealias MyThing<T> = Map<Class<T>, Supplier<T>>

[Caleb B]

I'm trying to specify that the type T is the same only for each individual entry, but different between different entries

[Sam]

Oh, I understand

[Caleb B]

For example, if I tell the map get(Foo::class), I know that the result will always be a Supplier<Foo> , but there's no way to specify that I know of

[Sam]

You can't do it with a regular Map, and I don't know of any other built-in type that does it, but it's easy enough to express it in the type system:

interface SupplierMap {
  fun <T> get(type: KClass<T>): Supplier<T>
}