My thoughts & tries with rvalue references

[Dicebot]

After some thinking on topic I come to conclusion that rvalue 
refs _should_ be "scope ref" and stuff like "ref int f(@temp ref 
int x) { return x; }" is invalid. I can see no valid use case for 
such an error-prone case. Contrary, "scope ref" feels just like 
it was designed for this task, also a good moment to actually 
define what "scope" means.