New expression in ToElemVisitor

[kinke]

On Monday, 20 August 2018 at 11:30:15 UTC, Jacob Carlborg wrote:
> Yes, it's for Objective-C, as we discussed earlier [1].

Glancing over the original thread again, you could probably 
tackle this differently. What about defining the `_class_t` 
struct and its helper structs in object.d and stashing away that 
type (just like `Type::dtypeinfo` etc.), so that you can use it 
later for defining the ObjC global (and presumably also for your 
<NewExpression>::type)?