Pop quiz, what does this do?

[Steven Schveighoffer]

On 3/3/21 11:52 AM, Dukc wrote:
> On Wednesday, 3 March 2021 at 16:06:48 UTC, Steven Schveighoffer wrote:
> 
>> import std.traits;
>>
>> interface I
>> {
>>    int foo();
>> }
>>
>> pragma(msg, FieldNameTuple!I);
>>
>> Without looking up the docs, or trying it, what do you think it does?
> 
> I'd think it either returns nothing, or the typeid and monitor fields 
> (or whatever they are)  that all classes are supposed to have.

It does neither of those things.

-Steve