Specifying @nogc on structs seems to have no effect

[Craig Black]

I've recently tried coding in D again after some years.  One of 
my earlier concerns was the ability to code without the GC, which 
seemed difficult to pull off.  To be clear, I want my programs to 
be garbage collected, but I want to use the GC sparingly so that 
the mark and sweep collections will be fast.  So I want 
guarantees that certain sections of code and certain structs will 
not require the GC in any way.

I realize that you can allocate on the non-GC heap using malloc 
and free and emplace, but I find it troubling that you still need 
to tell the GC to scan your allocation. What I would like is, for 
example, to be able to write a @nogc templated struct that 
guarantees that none of its members require GC scanning.  Thus:

@nogc struct Array(T)
{
   ...
}

class GarbageCollectedClass
{
}

void main()
{
   Array!int intArray; // fine


}