Hi,

Consider this code:

```
import core.atomic;

struct MyStruct
{
    uint a, b;
}
static assert(MyStruct.sizeof == ulong.sizeof);

void main()
{
    shared MyStruct ms1;

    MyStruct ms2 = atomicLoad(ms1);     // This is fine

    MyStruct ms3;
    cas(&ms1, ms2, ms3);                // This is also fine

    atomicStore(ms1, ms2);              // This gives a compile error
}
```

This used to work in DMD 2.088.1. It does not work in the latest DMD 2.091.0-beta.2. It gives a compile error like this:

```
/home/ec2-user/dlang/dmd-2.091.0-beta.2/linux/bin64/../../src/druntime/import/core/internal/atomic.d(233): Error: template core.internal.atomic.atomicExchange cannot deduce function from argument types !(cast(MemoryOrder)5, false)(MyStruct*, MyStruct), candidates are:
/home/ec2-user/dlang/dmd-2.091.0-beta.2/linux/bin64/../../src/druntime/import/core/internal/atomic.d(291):        atomicExchange(MemoryOrder order = MemoryOrder.seq, bool result = true, T)(T* dest, T value)
  with order = order,
       result = false,
       T = MyStruct
  whose parameters have the following constraints:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  > is(T : ulong)
    or:
  > is(T == class)
    or:
  > is(T == interface)
    or:
  > is(T U : U*)
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  Tip: not satisfied constraints are marked with >
/home/ec2-user/dlang/dmd-2.091.0-beta.2/linux/bin64/../../src/druntime/import/core/atomic.d(127): Error: template instance core.internal.atomic.atomicStore!(cast(MemoryOrder)5, MyStruct) error instantiating
/home/ec2-user/dlang/dmd-2.091.0-beta.2/linux/bin64/../../src/druntime/import/core/atomic.d(142):        instantiated from here: atomicStore!(cast(MemoryOrder)5, MyStruct, MyStruct)
atomic_test.d(18):        instantiated from here: atomicStore!(cast(MemoryOrder)5, MyStruct, MyStruct)
```

Is this supposed to not work anymore? Or is this a bug?

Thanks,
Saurabh

On Tuesday, 3 March 2020 at 09:12:40 UTC, Saurabh Das wrote:
> Is this supposed to not work anymore? Or is this a bug?

That is a bug, see https://issues.dlang.org/show_bug.cgi?id=20629

On Tuesday, 3 March 2020 at 10:57:36 UTC, MoonlightSentinel wrote:
> On Tuesday, 3 March 2020 at 09:12:40 UTC, Saurabh Das wrote:
>> Is this supposed to not work anymore? Or is this a bug?
>
> That is a bug, see https://issues.dlang.org/show_bug.cgi?id=20629

Oh wow you fixed it already! Amazing!

Thanks MoonlightSentinel.

Saurabh

PS: Any chance this will make it into DMD 2.091.0?

On Tuesday, 3 March 2020 at 11:04:53 UTC, Saurabh Das wrote:
> PS: Any chance this will make it into DMD 2.091.0?

Yes, this fix will be in the upcoming release.

On Tuesday, 3 March 2020 at 11:35:35 UTC, MoonlightSentinel wrote:
> On Tuesday, 3 March 2020 at 11:04:53 UTC, Saurabh Das wrote:
>> PS: Any chance this will make it into DMD 2.091.0?
>
> Yes, this fix will be in the upcoming release.

Excellent.

Thank you so much! :)

Saurabh