One step out of the TypeInfo stalemate

[Paul Backus]

On Wednesday, 29 July 2020 at 16:46:55 UTC, Alexandru Ermicioi 
wrote:
> On Wednesday, 29 July 2020 at 13:27:02 UTC, Paul Backus wrote:
>>
>> Well, just about anything is better than the current __traits 
>> syntax. IMO an easy improvement would be to provide some 
>> syntax sugar so you could write
>>
>>     T.__hasMember("member")
>>
>> and the compiler would lower it to
>>
>>     __traits(hasMember, T, "member")
>
> Yep, true. Though, there is already a proper place for such 
> reflection logic which are type info classes, hence I think 
> lots of methods found in std.traits could just be moved under 
> right type info classes.

The main disadvantage of using TypeInfo for this is that it 
doesn't work without the D runtime (i.e., in BetterC).

It's also a bit less efficient. A __traits expression is 
essentially a single function call inside the compiler. Using 
TypeInfo requires CTFE and/or template instantiation, so 
switching std.traits to it would make compile times (slightly) 
longer.