What is the Correct way to Malloc in @nogc section?

[Kitt via Digitalmars-d-learn]

I realized the above "_new" has an issue with emplace depending 
on whether it's a class (reference type) or not. Class c = 
emplace() works, but something like string s = emplace() does 
not. Is doing string s = *emplace() safe and okay? Or is there a 
better way to handle the differences between allocating a Class 
with malloc vs a non-Class?