https://issues.dlang.org/show_bug.cgi?id=17934

Nick Treleaven <nick@geany.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |nick@geany.org

--- Comment #9 from Nick Treleaven <nick@geany.org> ---
(In reply to Mike Franklin from comment #7)
> What about having `scope` apply to return values of functions, so `list()`
> could be written as `scope List list() @trusted`?

That might work there, but what about when a method wants to specify that the return value is `scope`? The `scope` attribute would be interpreted as applying to the `this` reference, when we might need a smaller scope. I really wish `this` parameter qualifiers were only allowed after the parameter list to avoid ambiguities.

--

https://issues.dlang.org/show_bug.cgi?id=17934

--- Comment #10 from Dlang Bot <dlang-bot@dlang.rocks> ---
dlang/dmd pull request #13926 "Revert "fix Issue 17934 - [scope] scopeness entrypoint for unique/ref…" was merged into master:

- 70d7a4799c62598d0f4ddc2d7ed3fcb0fd19e6f9 by Dennis Korpel:
  Revert "fix Issue 17934 - [scope] scopeness entrypoint for unique/ref-counted
missing"

  This reverts commit 18ad1685dcdca65070f7a1d89efa4410a5936895.

https://github.com/dlang/dmd/pull/13926

--

https://issues.dlang.org/show_bug.cgi?id=17934

Iain Buclaw <ibuclaw@gdcproject.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P4

--

https://issues.dlang.org/show_bug.cgi?id=17934

Paul Backus <snarwin+bugzilla@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |snarwin+bugzilla@gmail.com

--- Comment #11 from Paul Backus <snarwin+bugzilla@gmail.com> ---
One workaround for this is to pass the value to a callback as a scope parameter, rather than returning it:

---
void withList(alias callback)()
{
    scope l = (() @trusted => List(malloc(1)))();
    callback(l);
}

void test() @safe
{
    Elem elem;
    withList!((scope ref l) {
        elem = l.front; // scope variable `l` assigned to `elem` with longer
lifetime
    });
}
---

--

https://issues.dlang.org/show_bug.cgi?id=17934

--- Comment #12 from Nick Treleaven <nick@geany.org> ---
If you define `front` as `return`, *not* `return scope`:

    Elem front() @safe return

You get an error for:

    elem = l.front;

I think that fixes this issue, though that feature may need documenting.

--

https://issues.dlang.org/show_bug.cgi?id=17934

Dlang Bot <dlang-bot@dlang.rocks> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |pull

--- Comment #13 from Dlang Bot <dlang-bot@dlang.rocks> ---
@ntrel created dlang/dlang.org pull request #3619 "[spec/function] Document `return` parameters without `scope`" fixing this issue:

- [spec/function] Document `return` parameters without `scope`

  Fixes Issue 17934 - [scope] scopeness entrypoint for unique/ref-counted
  missing.

https://github.com/dlang/dlang.org/pull/3619

--

https://issues.dlang.org/show_bug.cgi?id=17934

--- Comment #14 from Dlang Bot <dlang-bot@dlang.rocks> ---
dlang/dlang.org pull request #3619 "[spec/function] Improve `return` struct method attribute docs" was merged into master:

- 17763b0db20cc9978c0000c8729bd13f96f2987b by Nick Treleaven:
  [spec/function] Document `return` parameters without `scope`

  Part of Issue 17934 - [scope] scopeness entrypoint for unique/ref-counted
  missing.

  Add 'Struct Return Methods' subheading.

https://github.com/dlang/dlang.org/pull/3619

--