I didn't get any response in learn for this so I will ask it here.

TypeInfo_Class.interfaces[n].classinfo has TypeInfo_Class and not TypeInfo_Interface?

Is this correct? Or is it a bug?
Doesn't make much sense to me.

Also the following code prints false so there are some consequences to this.
# # ]]]]]]]]]]]]
import std.stdio;
void main(string[] args) {
	writeln(typeid(c).interfaces[0].classinfo == typeid(i)); // false
}
interface i {}
class c : i {}

What is the proper way to handle this mismatch?
Is this mismatch intended or just some implementation detail?
Peoples thoughts on this?

On Sunday, 24 December 2017 at 05:21:44 UTC, Tofu Ninja wrote:
> I didn't get any response in learn for this so I will ask it here.
>
> TypeInfo_Class.interfaces[n].classinfo has TypeInfo_Class and not TypeInfo_Interface?
>
> Is this correct? Or is it a bug?
> Doesn't make much sense to me.
>
> Also the following code prints false so there are some consequences to this.
> # # ]]]]]]]]]]]]
> import std.stdio;
> void main(string[] args) {
> 	writeln(typeid(c).interfaces[0].classinfo == typeid(i)); // false
> }
> interface i {}
> class c : i {}
>
> What is the proper way to handle this mismatch?
> Is this mismatch intended or just some implementation detail?
> Peoples thoughts on this?

I guess I will just not get an answer to this, seems like just some weirdness of D that will just stick there. The typeinfo system seems really half baked and really provides very little in terms of usefulness.

On Wed, 27 Dec 2017 23:28:27 +0000, Tofu Ninja wrote:

> On Sunday, 24 December 2017 at 05:21:44 UTC, Tofu Ninja wrote:
> 
> I guess I will just not get an answer to this, seems like just some weirdness of D that will just stick there. The typeinfo system seems really half baked and really provides very little in terms of usefulness.

What are you trying to do? Will std.traits.InterfacesTuple[1] or BaseTypeTuple[2] do what you need?


[1]: https://dlang.org/phobos/std_traits.html#.InterfacesTuple [2]: https://dlang.org/phobos/std_traits.html#.BaseTypeTuple

On 12/27/17 6:28 PM, Tofu Ninja wrote:
> On Sunday, 24 December 2017 at 05:21:44 UTC, Tofu Ninja wrote:
>> I didn't get any response in learn for this so I will ask it here.
>>
>> TypeInfo_Class.interfaces[n].classinfo has TypeInfo_Class and not TypeInfo_Interface?
>>
>> Is this correct? Or is it a bug?
>> Doesn't make much sense to me.
>>
>> Also the following code prints false so there are some consequences to this.
>> # # ]]]]]]]]]]]]
>> import std.stdio;
>> void main(string[] args) {
>>     writeln(typeid(c).interfaces[0].classinfo == typeid(i)); // false
>> }
>> interface i {}
>> class c : i {}
>>
>> What is the proper way to handle this mismatch?
>> Is this mismatch intended or just some implementation detail?
>> Peoples thoughts on this?
> 
> I guess I will just not get an answer to this, seems like just some weirdness of D that will just stick there. The typeinfo system seems really half baked and really provides very little in terms of usefulness.

I'm not even sure why TypeInfo_Interface exists. It seems to be a thin wrapper over its TypeInfo_Class member `info`. TypeInfo_Class itself has an overridable `info` member which is never overridden, so I'm not sure what the purpose of that is either.

Looking at the implementation of TypeInfo_Interface, it appears that the only reason to have it, is to allow using interfaces as hash keys. But the blunt casting there, I don't think is right. Not all interfaces can be cast to Object.

I'll note that opEquals is also implemented incorrectly.

IMO, TypeInfo_Interface should be derived from TypeInfo_Class, and simply override the equals/getHash/compare functions. Then change the type of 'classinfo' inside the Interface struct to TypeInfo_Interface.

The compiler needs to be updated for this of course.

So in short, I think there are bugs here, but probably not what you expected.

-Steve