I've created DIP for my pull request.
DIP: http://wiki.dlang.org/DIP66
PR: https://github.com/D-Programming-Language/dmd/pull/3998

Please, comment it.

On 10/10/14 1:09 PM, IgorStepanov wrote:
> I've created DIP for my pull request.
> DIP: http://wiki.dlang.org/DIP66
> PR: https://github.com/D-Programming-Language/dmd/pull/3998
>
> Please, comment it.
Hm... not sure you need a DIP.

From page 231 of TDPL: "A class could introduce any number of alias this declarations, thus subtyping any number of types."

-Steve

On Friday, 10 October 2014 at 17:31:23 UTC, Steven Schveighoffer wrote:
> On 10/10/14 1:09 PM, IgorStepanov wrote:
>> I've created DIP for my pull request.
>> DIP: http://wiki.dlang.org/DIP66
>> PR: https://github.com/D-Programming-Language/dmd/pull/3998
>>
>> Please, comment it.
> Hm... not sure you need a DIP.
>
> From page 231 of TDPL: "A class could introduce any number of alias this declarations, thus subtyping any number of types."
>
> -Steve

TDPL tells that multiple alias this should be allowed, but tell nothing about conflict resolving. General idea of this DIP is sistematize rules for alias this. Please comment this part. Maybe I've forgot some cases, maybe introduce dangerous semantic rule.

On Friday, 10 October 2014 at 17:31:23 UTC, Steven Schveighoffer wrote:
> On 10/10/14 1:09 PM, IgorStepanov wrote:
>> I've created DIP for my pull request.
>> DIP: http://wiki.dlang.org/DIP66
>> PR: https://github.com/D-Programming-Language/dmd/pull/3998
>>
>> Please, comment it.
> Hm... not sure you need a DIP.
>
> From page 231 of TDPL: "A class could introduce any number of alias this declarations, thus subtyping any number of types."
>
> -Steve

Igor was asked to write a DIP for it by Walter and Andrei. Here's the context: https://github.com/D-Programming-Language/dmd/pull/3998#issuecomment-58286631

On 10/10/14, 10:09 AM, IgorStepanov wrote:
> I've created DIP for my pull request.
> DIP: http://wiki.dlang.org/DIP66
> PR: https://github.com/D-Programming-Language/dmd/pull/3998
>
> Please, comment it.

Thanks, will do. Everybody interested please chime in! -- Andrei

On 10/10/14, 10:31 AM, Steven Schveighoffer wrote:
> On 10/10/14 1:09 PM, IgorStepanov wrote:
>> I've created DIP for my pull request.
>> DIP: http://wiki.dlang.org/DIP66
>> PR: https://github.com/D-Programming-Language/dmd/pull/3998
>>
>> Please, comment it.
> Hm... not sure you need a DIP.
>
>  From page 231 of TDPL: "A class could introduce any number of alias
> this declarations, thus subtyping any number of types."

TDPL is not reference. The DIP should cover various corner cases. -- Andrei

On 10/10/14 2:17 PM, Andrei Alexandrescu wrote:
> On 10/10/14, 10:31 AM, Steven Schveighoffer wrote:
>> On 10/10/14 1:09 PM, IgorStepanov wrote:
>>> I've created DIP for my pull request.
>>> DIP: http://wiki.dlang.org/DIP66
>>> PR: https://github.com/D-Programming-Language/dmd/pull/3998
>>>
>>> Please, comment it.
>> Hm... not sure you need a DIP.
>>
>>  From page 231 of TDPL: "A class could introduce any number of alias
>> this declarations, thus subtyping any number of types."
>
> TDPL is not reference. The DIP should cover various corner cases. -- Andrei
>

OK, thanks everyone. I thought DIPs were specifically for proposals that had not been already approved.

-Steve

On Friday, 10 October 2014 at 17:09:08 UTC, IgorStepanov wrote:
> I've created DIP for my pull request.
> DIP: http://wiki.dlang.org/DIP66
> PR: https://github.com/D-Programming-Language/dmd/pull/3998
>
> Please, comment it.

There is an error in the wiki formatting in the second code block. (`{| class="wikitable"` should not be there)

I don't see any problems with the actual content of the DIP.

On Friday, 10 October 2014 at 17:09:08 UTC, IgorStepanov wrote:
> I've created DIP for my pull request.
> DIP: http://wiki.dlang.org/DIP66
> PR: https://github.com/D-Programming-Language/dmd/pull/3998
>
> Please, comment it.

I understand that as a first step it was suggested to implement the strictest behaviour regarding conflicts, namely to disallow them entirely.

However, I think more permissive strategies are useful, like in this example:
https://github.com/D-Programming-Language/dmd/pull/3998#issuecomment-58570742

Conflict resolution can work like overload resolution, with different levels of matching and partial ordering.

On 10/10/14 1:09 PM, IgorStepanov wrote:
> I've created DIP for my pull request.
> DIP: http://wiki.dlang.org/DIP66
> PR: https://github.com/D-Programming-Language/dmd/pull/3998
>
> Please, comment it.

This part:

void test()
    {
        C c;
        int i = c; //Error: c.a.i vs c.b.i
    }

    static assert(is(C : int)); //Ok, because C is subtype of int anyway.

I think might be wrong. There is a lot of code out there that says, e.g.:

void foo(T)(T t) if(is(T : U))
{
  U u = t;
  ...
}

Which will now create an error in the wrong place. IMO, the 'is' test should also fail.

-Steve