On Monday, 22 October 2018 at 12:03:22 UTC, test wrote:
> On Monday, 22 October 2018 at 11:59:21 UTC, test wrote:
>> On Monday, 22 October 2018 at 11:42:59 UTC, test wrote:
>> I try made a simple example but it has no error:
>
>
> I find the way to show the error:
>
> https://run.dlang.io/is/f8cULz
>
>
> import std.traits;
>
> struct FiberS {
> 	static auto getThis(){
> 		return Fiber.getId();
> 	}
> }
>
> struct Proxy(T){
>  	T* ptr;
>     alias getPayload this;
>
> 	@property ref auto getPayload() inout return {
> 		return * ptr ;
> 	}
>
>     static auto getId(){
>         return 1;
>     }
> }
> alias Fiber = Proxy!(FiberS);
>
>
> extern(C) void main(){
>        auto id = Fiber.getThis(); // work here
> }
>
> struct TcpStream {
>     void read(ubyte[] data){
>            auto id = Fiber.getThis(); // not work here in my case
>     }
> }

Let's analyze this call:

auto id = Fiber.getThis();

You're trying to call a static function 'getThis' on Fiber.
The type 'Fiber' is really a Proxy!FiberS. Proxy doesn't have a static getThis() function. So the compiler tries an 'alias this', which forwards to a non-static member function getPayload(). To call that function, you need an instance of 'Proxy', which you don't have.
I guess the first error message ("this for getPayload needs to be type Proxy not type TcpStream") just doesn't report that clearly.

On Monday, 22 October 2018 at 12:16:50 UTC, Stanislav Blinov wrote:
> On Monday, 22 October 2018 at 12:03:22 UTC, test wrote:
> You're trying to call a static function 'getThis' on Fiber.
> The type 'Fiber' is really a Proxy!FiberS. Proxy doesn't have a static getThis() function. So the compiler tries an 'alias this', which forwards to a non-static member function getPayload(). To call that function, you need an instance of 'Proxy', which you don't have.
> I guess the first error message ("this for getPayload needs to be type Proxy not type TcpStream") just doesn't report that clearly.


But this work:

> extern(C) void main(){
>        auto id = Fiber.getThis(); // work here
> }

here also dont have Fiber instance.

On Monday, 22 October 2018 at 12:32:57 UTC, test wrote:
> On Monday, 22 October 2018 at 12:16:50 UTC, Stanislav Blinov wrote:
>> On Monday, 22 October 2018 at 12:03:22 UTC, test wrote:
>> You're trying to call a static function 'getThis' on Fiber.
>> The type 'Fiber' is really a Proxy!FiberS. Proxy doesn't have a static getThis() function. So the compiler tries an 'alias this', which forwards to a non-static member function getPayload(). To call that function, you need an instance of 'Proxy', which you don't have.
>> I guess the first error message ("this for getPayload needs to be type Proxy not type TcpStream") just doesn't report that clearly.
>
>
> But this work:
>
>> extern(C) void main(){
>>        auto id = Fiber.getThis(); // work here
>> }
>
> here also dont have Fiber instance.


I think this is a bug.

If I use "alias this " with a FiberS instance tuple memebr, it will work.  but if I use alias this with @propery , it only work on static method, on delegate method it will use delegate this.

This is kind like Javascript method this is come from caller place. I think it is a bug.  please help me confirm this.  If so please made a bug report for me.