Automatically using stack allocations instead of GC

[Per Nordlöw]

On Monday, 23 October 2017 at 10:48:37 UTC, Walter Bright wrote:
> There are no plans at the moment, but it's a good idea that 
> `scope` can make possible.

I'm glad your open for such automatic optimizations, Walter. 
Making D compilers automate these things which are cumbersome 
manual labour in languages such as Rust is, IMHO, the competitive 
way forward for D.

>> And how does/should/will this interact with `@nogc`?
>
> If it gets allocated on the stack, then it should be compatible 
> with @nogc.

Great. I believe good diagnostics (for, in this case, mismatches 
between allocations and qualifiers) will play a key role in this 
regard.