Type System Implementation

The production checker consumes resolved HIR through run_production_typeck_hir. The normative rules live in docs/spec/type_system.md and schemas/type_system/rules.json.

• checker.vit: declarations, statements, returns, impl coherence, and exhaustiveness.
• infer.vit: expression typing, substitutions, calls, members, and casts.
• unify.vit and coercion.vit: common types and directional conversions.
• traits.vit: primitive capabilities and trait facts.
• errors.vit: structured diagnostics and cause chains.

tools/check_type_system_rules.py enforces the mapping from formal rules to compiler code and production tests.