On Friday, 24 June 2022 at 18:31:14 UTC, Ola Fosheim Grøstad
wrote:
The objects are in the calling function, not in the connect()
function. So they are not destroyed when the connect() function
returns.
When `connect()` returns may happen that `b` is destroyed but `a`
not, so `a.next` contains a dangling pointer that will bring
potential segmentation faults that could be detected only with
tools like Valgrind, just consider
```d
node * calling(return scope node * a) @safe{
scope node *b = new node(); //b is stack allocated
connect(a, b);
return a;
//b destroyed but a not
}
```
The `scope` attribute tries to avoid these events preventing you
from doing something potentially dangerous with stack allocated
objects, and assigning a `scope` pointer to a not-scoped variable
(`a.next` is not `scope` since this attribute is not transitive)
is clearly dangerous since `connect` doesn't know which between
`a` and `b` terminates first.
