Scala prohibiting parameterization of a specific type

Question

Is there a way to prohibit a parameterized type being parameterized by a specific type?

e.g. Suppose I want to create my own specialized List[T] type where I do not want List[Nothing] to be legal, i.e. cause a compile error.

I'm looking for a way to make the following error more easy to catch (yes, I understand this is not very functional or great Scala):

val x = ListBuffer()
x += 2

x has type ListBuffer[Nothing].

Answer 1

This sort of works,

class C[A](x: A*)(implicit ev: A =:= A) { }

There will be a type error if A = Nothing is inferred,

val c1 = new C[Int]() // Ok
val c2 = new C(1)     // Ok, type `A = Int` inferred
val c3 = new C()      // Type error, found (Nothing =:= Nothing) required: (A =:= A)

But it's still possible to explicitly set the type parameter A to Nothing,

val c4 = new C[Nothing]() // Ok

More generally, it's pretty tricky to ensure that two types are unequal in Scala. See previous questions here and here. One approach is to set up a situation where equal types would lead to ambiguous implicits.