A while ago one of commenters here hinted to me at the existence of such a proposal. I didn't know the exact proposal then, but after a while of struggling with

A while ago one of commenters here hinted to me at the existence of such a proposal. I didn't know the exact proposal then, but after a while of struggling with this part of Rust I decided to go looking for it. I've found it, but, to my dismay, the proposal was rejected. Posting here as a curiosity for others.