Imagine you're in the following situation:

• You need serde::Serialize implemented for a struct that doesn't already have it
• This struct contains a lot of fields with lots of types from other crates in the workspace that also don't have serde::Serialize derived yet

You now have to spend minutes of your time clicking through to all of the different types and adding #[derive(Serialize)] to them (plus relevant imports).

What if Rust Analyzer could do this for us? There could be an assist on #[derive(Serialize)] for the top-level type that said "Derive recursively for all children" and went through and automatically did all of this work.