Current sentiment on Nullable.get

[Sebastiaan Koppe]

On Tuesday, 11 December 2018 at 22:32:45 UTC, Jonathan M Davis 
wrote:
> the property isNull became confusing to some folks, because 
> they thought that the null value of a pointer and whether the 
> Nullable itself was null were related, when they're not (and if 
> they were, it would cause subtle bugs - especially in generic 
> code).

Could you elaborate on some of those subtle bug? And are they 
worse than the following?

---
import std.typecons;
class C {
}
void main() {
     Nullable!C c;
     assert(c.isNull);
     c = null;
     assert(!c.isNull);
}
---

What about having Nullable!T* decay into a wrapped pointer. Why 
does it need to keep its own bool when that information can be 
captured in the pointer?

Or is there some difference between a Nullable!T* with a null 
value and one with no value? I thought no value and null to be 
the same thing. But if it is, why is it called Nullable?