Debugging

1. Tree dumps: walk with tree.cursor() printing nodeType + spans (the tree_walk example pattern) — most "wrong tree" reports become obvious here.
2. Loggers: parser.setLogger(.{ .level = .debug }) streams shifts, reductions, recovery, and reuse decisions; .trace adds lexer events.
3. Tracers: Tracer records structured events for programmatic inspection and replay.
4. Bisection: shrink the source to the smallest failing span, then check token coverage (unmatched bytes) and table coverage (missing actions) at that state.

Related: Logging, Troubleshooting, Debugging examples.