# Code Review Issues - Iteration 1a604562

## BLOCKING Issues

### 1. CV Threshold Failures (BLOCKING)
**Severity**: BLOCKING
**File**: `benches/parser_benchmarks.rs`

**Issue**: Acceptance criteria require "CV < 5% for all benchmarks", but actual measurements show:
- `parser_simple`: CV = 45.4% (570353.57 / 1256842.13 * 100)
- `parser_complex`: CV = 2.98% ✓ (meets threshold)
- `parser_variables`: CV = 6.07% (47615.83 / 784669.31 * 100)

**Analysis**: The coder increased Criterion configuration parameters (sample_size=1000, measurement_time=30s, warm_up_time=5s) to address CV failures, but this was insufficient:
1. `parser_simple` has extremely high variance (45.4%) - 9x over threshold
2. `parser_variables` is only slightly over (6.07% vs 5%) but still fails the requirement
3. The 12000-iteration batching approach may be introducing its own variance

**Impact**: Core acceptance criterion not met. The benchmark results cannot be trusted for performance regression detection with such high variance.

**Why Blocking**: Acceptance criteria explicitly state "CV < 5% for all benchmarks". This is a functional requirement failure - 2 out of 3 benchmarks fail to meet the specified quality threshold.

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## Summary

The implementation correctly:
- ✓ Created `benches/parser_benchmarks.rs` at the correct location
- ✓ Implements all three required benchmarks: `parser_simple`, `parser_complex`, `parser_variables`
- ✓ Pre-tokenizes input outside benchmark loop (isolates parser performance)
- ✓ Criterion generates `estimates.json` files for each benchmark

However, it fails the critical acceptance criterion:
- ❌ **CV < 5% for all benchmarks**: Only 1/3 benchmarks meet this threshold

**Root Cause**: The 12000-iteration batching approach combined with Criterion configuration appears insufficient for achieving CV < 5% on the fast parser operations (80-250ns per parse). The variance is particularly extreme for `parser_simple` (45.4% CV).
