On 8/21/2018 8:58 PM, Nicholas Wilson wrote:
On Tuesday, 21 August 2018 at 14:31:02 UTC, Atila Neves wrote:
The problem is that the code we write doesn't deal directly with pointers -
see the recent confusion in this forum over where `scope` on the left applies
to the `this` pointer or the one returned by the member function.
Kagamin just told me I needed to use `return` instead of `scope` to get things
to work and I'm still not sure why.
The way I think about it is if you have a function that takes a pointer, any
pointer, and either returns it or a pointer derived from it (dereferencing or
indexing) that argument must be marked `return`. In your case it was a pointer
derived from `this` so `return` must be applied to `this`.
Another way to think about it is this:
S s;
return &s;
We all know that is an error. The idea is to have a way to express that for:
S s;
return s.foo();
and:
S s;
return foo(&s);
so that the compiler knows that the return value of foo() is attached to the
lifetime of s. Pretty much everything flows from that.
