Hi! I've prepared a proposal (draft), which aims to provide guaranteed copy
elision for common cases of local variables being returned from a function.

The proposal link:
https://gist.github.com/Anton3/594141354ff9625db0b85775799312c7

I need someone with a fresh head to read and reconcile it. There could be
some grammar mistakes or mistakes in the formal specification. I also need
feedback on feasibility of the proposal, especially from compiler writers.

I'll have to fix up the mistakes and rewrite the document in LaTeX until
the end of the week, or mid next week. If you are going to fix up stuff on
yourself and would prefer a Github repo or Google Docs, please let me know.