Understanding precise capture syntax and constraints

Hello 👋, I'm trying to understand the new precise capture syntax. To my understanding it has been introduced to opt-out of the new all parameter capture behaviour - the new default with Edition 2024. When playing around with it I noticed a few things I don't understand. I created an (non-compiling) example on the rust playground for reference: In the current state Rust requires you to mention all type parameters which may/can or may/can not be lifted in the future, but what I don...