Feature request: lifetime range visualizations

Showing a lifetime's range in code would be great for lifetime related debugging and for education. A simple way to show this is that when mouse hovering a lifetime marker 'a or a variable, with a range of code highlighted.

I was trying to do something like this but I realized there's no way to get a lifetime info anywhere. I think it's now internal to rustc. I checked rust-analyzer, RLS, rls-analysis and none of them seems to be able to provide such info.

I asked in rust internals forum and they said it's not possible now, and I shall check back later when the stable MIR project is ready.

Before that, is it possible for rust-analyzer to implement the lifetime analysis (and/or borrow checking) so that we can start on our end?

Start by reading the rust-analyzer issue context, the linked Rust Internals discussion, and the stable MIR project status to determine whether lifetime information is available. Done would require a concrete implementation path for exposing lifetime ranges or a documented conclusion that the prerequisite compiler information is unavailable.