[Issue 23140] Array!T where T is a shared class no longer works

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=23140

RazvanN <razvan.nitu1305 at gmail.com> changed:

           What    |Removed                     |Added
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                 CC|                            |razvan.nitu1305 at gmail.com

--- Comment #4 from RazvanN <razvan.nitu1305 at gmail.com> ---
(In reply to Steven Schveighoffer from comment #0)
> I'm not sure it should have ever worked, but I'm also wondering why this
> cannot be made to work.
> 
> Prior to 2.099.0, the following code compiled:
> 
> ```d
> import std.container : Array;
> shared class C {}
> 
> Array!C arr;
> ```
> 
> But it no longer does. The reason is because of the fix for
> https://issues.dlang.org/show_bug.cgi?id=22515. Now, a C is actually typed
> as `shared(C)`, and it does not implicitly cast to `const void *` (used by
> GC functions and pureFree, etc.).
> 
> Three options here:
> 
> 1. Fix Array to cast away the shared when using these functions (a
> reasonable assumption)

>From my perspective, it should be illegal to cast away the sharedness if an
aggregate was defined `shared struct/class T` (this could be extended to any
type qualifier, but let's just stick to shared). If the user opted to define
the aggregate as such, I think it is reasonable to assume that any use of such
an object is going to violate the definition of the object.

> 2. Fix the druntime functions so they also accept `shared` pointers

In my opinion, this is the most sensible approach.

> 3. close this bug as wontfix, and I'll have to work around it in the project
> I'm trying to compile (libasync)

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