Does `is` expression with template alias need fixing.

[Timon Gehr]

On 3/23/23 01:23, Elfstone wrote:
> On Wednesday, 22 March 2023 at 11:00:40 UTC, zjh wrote:
>> On Wednesday, 22 March 2023 at 10:43:15 UTC, Elfstone wrote:
>>> ```C++
>>> template <typename T>
>>> using Vector3 = Matrix<T, 3, 1>;
>>> ```
>>>
>>> I declare an alias and I use it everywhere. It acts as a natural 
>>> constraint. I never needed `isVector3` with my old C++ code. I 
>>> expected D could do the same, and was really frustrated when I found 
>>> out it couldn't. Even more frustrated when I read Steven's reply, 
>>> that the bug with `is` has been there for 16 years.
>>>
>>
>> When you have questions, please file a bugzilla.
>> D is only for `specific problems`, please describe the problem carefully.
> 
> There are already a ton issues about this filed, including Steven's 16 
> years old one. It seems the community lacks the motivation to fix it. 
> That's why I started this thread.

That's just not true. People are motivated enough to fix it technically, 
but not to go through the motions needed to get their contribution 
actually accepted into the language.

https://forum.dlang.org/post/kvcrsoqozrflxibgxtlo@forum.dlang.org
https://github.com/dlang/dmd/pull/9778
https://github.com/dlang/DIPs/blob/master/DIPs/other/DIP1023.md#reviews

However, unfortunately the DIP process is often where contributions go 
to die. I guess one reason for this is because it is not so easy to 
enforce your own quality standards on the volunteer work of others and 
people have different priorities.