In the language spec here :-
https://dlang.org/spec/garbage.html#pointers_and_gc
It refers to a distinction between pointers to garbage collected
memory and pointers that are not. In particular it says that with
a non garbage collected pointer you can do anything that is
legal in C but with a garbage collected pointer there are a lot
of undefined behaviors if you don't follow some restrictions.
My question is how do I tell if a pointer is "garbage collected"
or not?
For example :-
* Do not store magic values into pointers, other than null.
So how do I tell if it's safe to do this for any individual
pointer? What makes a pointer "garbage collected"?
