Debugging

Debug Rust by narrowing the scene, then changing one thing.

Rust debugging often starts with a precise compiler message and still ends in a messy system. Rustjar checklists keep both sides in view: the local type or ownership problem and the wider runtime context where async scheduling, feature flags, data shape, or deployment configuration can hide the real cause.

1. Copy the exact diagnostic and mark the first type mismatch, not the loudest line.
2. Reduce the lifetime of a borrow before cloning data to escape the error.
3. Add tracing around async boundaries where work changes ownership or task context.
4. Reproduce production panics with the same feature flags, environment, and input shape.
5. Confirm a performance fix with a repeatable baseline before changing two variables.