borrowed pointers vs ref

[Walter Bright via Digitalmars-d]

On 5/13/2014 6:36 AM, Dicebot wrote:
> Main problem about making `ref` borrowed pointer is that you will need to
> prohibit storing it in function transitively. This will need to become invalid
> code:
>
> struct A
> {
>      int* ptr;
> }
>
> int* gptr;
>
> void foo(ref A a)
> {
>      gptr = a.ptr; // error, can't leak borrowed a.ptr into global context
> }

The lifetime of &a is not at all the same as the lifetime of a.ptr, those are 
independent pointers. I.e. ref is not transitive (unlike const which is transitive).