- value_from_params now errors on ResultOut/ResultString params
  These are ABI return types and should never appear as input params.
  Returning an error prevents silently hiding bugs.

- Add pattern validation for match-on-unit
  When matching on Unit values, validate that only wildcard (_),
  binding, or unit literal patterns are used. This prevents generating
  nonsense comparisons against the dummy match value.

- Add tests:
  - unit_match_multi.cap: Match expression with Unit-returning arms
  - result_unit_ok.cap: Result<Unit, i32> payload handling

All tests pass (21 run tests, 29 typecheck tests).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

- Change unit match dummy from I8 to I32 to align with enum dispatch
  This reduces risk of accidental type mismatches since enum variants
  (the most common match case) use I32 tags.

- Add support for single-segment Path patterns as bindings
  The parser currently emits Pattern::Path for bare identifiers in
  match arms (e.g., `match () { x => ... }`). Added handling in:
  - match_pattern_cond: single-segment paths always match (like bindings)
  - bind_match_pattern_value: bind the value to the path identifier
  - Unit match validation: allow single-segment paths

- Verified that store_local correctly handles Unit without creating
  dummy values - it stores LocalValue::Value(ValueRepr::Unit) with
  no stack allocation, so bindings on unit are safe.

- Add unit_match_bind.cap test to verify binding patterns work
  correctly with unit values without forcing dummy value storage.

All 22 run tests and 29 typecheck tests pass.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

A) Improve always-true pattern condition clarity
   Changed from `icmp_imm(NotEqual, iconst(I8, 1), 0)` to:
   `let one = iconst(I32, 1); icmp_imm(Equal, one, 1)`

   While both work, the new version makes intent clearer (1 == 1 is
   obviously true). Attempted to use bconst(B1, true) but it doesn't
   exist in this Cranelift version. The explicit comparison is more
   readable than "1 != 0" and uses I32 (matching most other constants).

B) Remove Result binding restriction
   Previously bind_match_pattern_value rejected ValueRepr::Result.
   This was overly restrictive since store_local/load_local handle
   Result values correctly:
   - store_local: Result -> LocalValue::Value(Result)
   - load_local: LocalValue::Value(v) -> v.clone()

   Now binding patterns can bind any ValueRepr type, including Result.
   This enables patterns like `match result_value { x => ... }` where
   x is bound to the entire Result (though the parser doesn't currently
   use this pattern in practice - Ok/Err destructuring is more common).

All 22 run tests and 29 typecheck tests pass.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>