The relevant search terms are "SEME regions" and "non-lexical borrows". The tracking issue is here: https://github.com/rust-lang/rfcs/issues/811 and https://github.com/rust-lang/rust/issues/6393 is the older issue it superseded, with examples.

There hasn't been an RFC yet, because we're in the middle of a large amount of compiler internals work (HIR/MIR), which will make overall analysis easier, including these two features.

> (I can't reply there for some reason.)

HN limits responses based on the depth of the comment tree and the length of time since the comment was posted, to discourage flamewars, you can always click on a comment link directly to kind of bypass that though.