I think the author of that blog post fundamentally misunderstands the point: The damage of nullable pointers is not that they are nullable, but that compilers allow you to write code everywhere that assumes they’re not null (in fact, this is the
only possible way to code, when the language
cannot express the notion of a non-nullable reference!)
For example, most older languages with “the billion dollar mistake” have no complaint whatsoever when your write “object.method();” where it’s unknown at this scope whether “object” is null or not.
The fact that such code compiles is the billion dollar mistake; not the fact that the pointer is nullable.
I don’t care if you want to write nullable references everywhere, or whatever else you prefer or your application demands. That’s fine, so long as:
1. Non-nullable reference types must exist.
2. Nullable references types must exist as statically distinct from #1.
3. The compiler must not let you write code that assumes a nullable reference is not null, unless you check via a control flow statement first.
Now to take a step back, the principle behind this certainly applies beyond just nullability (if that was the point you were trying to make): Generally, dynamic, untyped invalidation states are dangerous/bad, while statically typed invalidation states are ideal. And yes, this does include bad states internal to a non-null reference, just as much as to a null reference.
Sum types are the key to being able to statically declare what range of values a function may return (or accept), and ensure at compile time that these different cases are all accounted for. If you aren’t aware of how elegantly sum types solve this, you should look into it — and I suspect it will be quickly clear why nullable references are useless, outdated, and harmful.
But at the very least, we’ve solved the pain of null dereference — and virtually without compromise. So, it’s irresponsible or ignorant IMO to create a new language that doesn’t include this solution in its core.