[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

Ruby The Roobster <rubytheroobster at yandex.com> changed:

           What    |Removed                     |Added
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                 CC|                            |rubytheroobster at yandex.com

--- Comment #1 from Ruby The Roobster <rubytheroobster at yandex.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.).
> 

I'm currently working on a fix, and I've noticed the following:

While creating an Unshared template
(https://forum.dlang.org/post/xigdpyblcgsyaawhywva@forum.dlang.org),
and doing the following solved most of the problems:

```d
//...
struct Array(W) //Changed from struct Array(T)
if (!is(immutable W == immutable bool)) //Change 'T' to 'W'
{
    alias T = Unshared!W; //Fix https://issues.dlang.org/show_bug.cgi?id=23140
    //...
```

This doesn't fix the constructor for Array.

I still get the following error message:

```
E:\Programs\D\dmd2\windows\bin\..\..\src\phobos\std\container\array.d(650):
Error: none of the overloads of template
`std.container.array.Array!(shared(C)).Array.__ctor` are callable using
argument types `!()(C[])`
E:\Programs\D\dmd2\windows\bin\..\..\src\phobos\std\container\array.d(575):    
   Candidates are: `__ctor(U)(U[] values...)`
E:\Programs\D\dmd2\windows\bin\..\..\src\phobos\std\container\array.d(605):    
                   `__ctor(Range)(Range r)`
  with `Range = C[]`
  must satisfy the following constraint:
`       !is(Range == T[])`
```

> Three options here:
> 
> 1. Fix Array to cast away the shared when using these functions (a
> reasonable assumption)
> 2. Fix the druntime functions so they also accept `shared` pointers
> 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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