Does it make sense to throw a type error if the value cannot be null for the `.toBeNull` helper?

[CristhianMotoche]

Does it make sense to throw a type error if a value cannot be null for the .toBeNull helper? For example, in the following test I WOULD expect a type error if the type cannot be null:

 it("cannot be null", () => {
 const x: number = 1;
 expect(x).toBeNull(); # Throw a type error here since `x` can only be a number?
 });

I WOULD NOT expect a type error if the value can be null. For example, in this test:

 it("cannot be null", () => {
 const x: number | null = 1;
 expect(x).toBeNull();
 });

Let me know if that makes sense.