On Tuesday, 21 August 2018 at 19:36:39 UTC, Walter Bright wrote:
On 8/21/2018 7:31 AM, 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.
That's what I was saying :-)
The way to deal with this is make a copy of the code, then
rewrite it so it does the exact same thing, but with pointers
and refs only. No member functions, no delegates, no dynamic
arrays. Then it is MUCH MUCH easier to see where the
annotations go.
Well, no. The syntax isn't the same for member functions. The
examples from the actual DIP don't compile. There it says:
-------
scope can be applied to function return values (even though it is
not a type qualifier). It must be applied to the left of the
declaration, in the same way ref is:
scope int* foo(); // applies to return value
--------
Except:
-------
struct MyStruct { scope int* foo() scope; }
foo.d(1): Error: redundant attribute scope
-------
Meaning the first `scope` actually applies to `this`. Writing
this out as a non-member function won't help me declare member
functions!
I still don't know how to return a ref/pointer that's scoped. And
I thought I'd written code that did that. Maybe I did. I'm very
confused.
BTW, the annotations do not break things. The worst that will
happen is the compiler will complain in @safe code that they
are incorrect, and you'll need to fix it or make it @trusted.
The compiler is also pretty good about inferring the correct
annotations, at least for templates and lambdas, which helps
enormously.
In my opinion, the worst that can happen is I successfully
compile my @safe code with -dip1000 and the resulting binary
isn't memory-safe, which is what's been happening to me.
However, dip1000 not working with Phobos is a huge impediment
to success, and so pulling 8504 is critical.
I don't have merge rights. I took a look anyway and it mostly
looks ok, but I'm not familiar enough with that part of the
codebase.
