# Hako Check — Diagnostics Contract (MVP)

This tool lints .hako sources and emits diagnostics.

Diagnostics schema (typed)
- Map fields:
  - `rule`: string like "HC011"
  - `message`: string (human-readable, one line)
  - `file`: string (path)
  - `line`: int (1-based)
  - `severity`: string ("error"|"warning"|"info"), optional (default: warning)
  - `quickFix`: string, optional

Backwards compatibility
- Rules may still `out.push("[HCxxx] ...")` with a single-line string.
- The CLI accepts both forms. String diagnostics are converted to typed internally.

Suppression policy
- HC012 (dead static box) takes precedence over HC011 (unreachable method).
- If a box is reported by HC012, HC011 diagnostics for methods in that box are suppressed at aggregation.

Quiet / JSON output
- When `--format json-lsp` is used, output is pure JSON (pretty). Combine with `NYASH_JSON_ONLY=1` in the runner to avoid extra lines.
- Non-JSON formats print human-readable lines per finding.

Planned AST metadata (parser_core.hako)
- `boxes[].span_line`: starting line of the `static box` declaration.
- `methods[].arity`: parameter count as an integer.
- `boxes[].is_static`: boolean.

Notes
- Prefer AST intake; text scans are a minimal fallback.
- For tests, use `tools/hako_check/run_tests.sh`.