Can you use RTTI to determine a union member?

[Christian Kamm]

> if A, B and C are classes then you can uses
> 
> (cast(A)(cast(Object)u.b) !is null)
> (cast(B)(cast(Object)u.c) !is null)
> (cast(C)(cast(Object)u.a) !is null)

If A, B, C are classes, you could also check with

u.a.classinfo is A.classinfo
u.a.classinfo is B.classinfo
u.a.classinfo is C.classinfo.

Christian