Pop quiz, what does this do?

[Dukc]

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.