Comment by int_19h

> It makes sense that you should be able to assign a pointer to a size. If the size is signed, this cannot be done due to its smaller capacity.

You can, since the number of bits is the same. The mapping of pointer bits to signed integer bits will mean that you can't then do arithmetic on the resulting integers and get meaningful results, but the behavior of such shenanigans is already unspecified with no guarantees other than you can get an integer out of a pointer and then convert it back later.

But also, semantically, what does it even mean to convert a single pointer to a size? A size of an object is naturally defined as the count of chars between two pointers, one pointing at the beginning of the object, the other at its end. Which is to say, a size is a subset of pointer difference that just happens to always be non-negative. So long as the implementation guarantees that for no object that non-negative difference will always fit in a signed int of the appropriate size, it seems reasonable to reflect this in the types.