Collections question

[Andrei Alexandrescu via Digitalmars-d]

On 12/01/2015 09:35 AM, Marc Schütz wrote:
> On Tuesday, 1 December 2015 at 14:15:47 UTC, Andrei Alexandrescu wrote:
>> On 12/1/15 4:55 AM, Marc Schütz wrote:
>>> On Monday, 30 November 2015 at 18:18:38 UTC, Andrei Alexandrescu wrote:
>>>> * The one matter with the value/RefCounted approach is that RefCounted
>>>> cannot be made @safe.
>>>
>>> That's just as true for internal refcounting.
>>
>> I don't think that's the case. The way I wrote code, safety can be
>> achieved with a few controlled insertions of @trusted. -- Andrei
>
> As long as you can pass the container and one of it's elements by
> mutable ref, it's unsafe (see the RCArray discussion [1]). If you can
> only access the elements by value (i.e. opIndex returns a copy), this
> precondition isn't fulfilled, but otherwise, I see no way to prevent it
> with the current language.
>
> [1] http://forum.dlang.org/post/huspgmeupgobjubtsmfe@forum.dlang.org

Ah, the good old assignment to reference. We need to prevent that from 
happening in safe code. Got any fresh ideas? -- Andrei