# Rust Review Report

**Branch**: feature/187-wave-3a--cst-linearization--pre-order-tr -> main
**Date**: 2026-06-01

## Issues in Your Changes (BLOCKING)

### CRITICAL

(none)

### HIGH

(none)

### MEDIUM

(none)

## Issues in Code You Touched (Should Fix)

(none)

## Pre-existing Issues (Not Blocking)

(none)

## Suggestions (Lower Confidence)

- **Consider implementing `FusedIterator`** - `ast_walk.rs:195` (Confidence: 65%) -- `AstWalkIter` already exhibits fused behavior (returns `None` forever after exhaustion), so implementing `std::iter::FusedIterator` would formalize this contract and enable downstream optimizations in adapters like `.fuse()`.

- **Duplicated `MAX_AST_DEPTH` / `MAX_AST_NODES` constants** - `linearize.rs:40-45`, `ast_extract.rs:21-24` (Confidence: 70%) -- Both consumers define identical `MAX_AST_DEPTH = 500` and `MAX_AST_NODES = 100_000`. Since `AstWalkConfig::default()` already encodes these as `500` / `100_000`, callers could reference `AstWalkConfig::default()` directly rather than maintaining parallel constant definitions. However, callers may intentionally want local control over these values, so this is a style preference rather than a defect.

- **`level_stack` initial capacity hint** - `ast_walk.rs:119` (Confidence: 60%) -- `Vec::new()` starts with zero capacity. Since `max_depth` is 500, the `level_stack` will reallocate several times during deep traversals. A `Vec::with_capacity(32)` or similar small pre-allocation could reduce early reallocation churn. The impact is minor given typical tree depths of 10-30.

## Summary

| Category | CRITICAL | HIGH | MEDIUM | LOW |
|----------|----------|------|--------|-----|
| Blocking | 0 | 0 | 0 | - |
| Should Fix | - | 0 | 0 | - |
| Pre-existing | - | - | 0 | 0 |

**Rust Score**: 9/10
**Recommendation**: APPROVED
