@nogc and NSAutoReleasePool-style regions.

[via Digitalmars-d]

A custom allocator can also be specified. The nice thing is, that 
this doesn't even need new syntax:

process(A a) {
     int x;
     {
         MyCustomAllocator alloc;
         GC.pushAllocator(alloc);
         scope(exit) GC.popAllocator();

	auto y = new ...;
         // alloc's destructor is called, which calls destructors 
of
         // allocated objects
     }
}

But as you already noted, there needs to be a mechanism to 
restrict escaping of pointers. Do you have some concrete idea how 
that could be solved? A more or less straight-forward way would 
be to encode the ownership/lifetime information somewhere in the 
types of the pointers (similar to how we use const and the like 
today). But this cannot be done, because it could not apply to 
external (non-template) functions.