On Efficient Concurrency, Sharing, Move Semantics in Rust vs D

["Nordlöw" via Digitalmars-d]

> but I believe it would be better to let the (D) compiler 
> optimization stage figure out _automatically_ if it needs to 
> make a copy of the variable `numbers` or not depending on 
> whether `numbers` is used or not further down the body of 
> `main`.

I just realized that solving this in an elegant way (for 
reference types) would require some kind of new builtin property, 
say,

     r.isUnique

The compiler could, when possible, do this check at compile-time, 
and avoid any run-time (GC) or reference counting overheads done 
in isUnique.

I just found that this is highly related: 
http://wiki.dlang.org/DIP29