hakorune/docs/development/current/main/phase170-d-fix-verification.md

Phase 170-D Bug Fix Verification

Date: 2025-12-07 Status: Fix Complete ✅ Impact: Function parameters now correctly classified as OuterLocal

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Summary

The LoopConditionScopeBox function parameter misclassification bug has been fixed. Function parameters (s, pos, etc.) are now correctly treated as OuterLocal instead of being incorrectly defaulted to LoopBodyLocal.

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Bug Fix Details

File: src/mir/loop_pattern_detection/condition_var_analyzer.rs

Root Cause:

• Unknown variables (not in variable_definitions) were defaulted to LoopBodyLocal
• Function parameters have no explicit definition in the loop body, so they appeared "unknown"
• Result: Valid loops using function parameters were incorrectly rejected

Fix:

pub fn is_outer_scope_variable(var_name: &str, scope: Option<&LoopScopeShape>) -> bool {
    match scope {
        None => false,
        Some(scope) => {
            // ① body_locals に入っていたら絶対に outer ではない
            if scope.body_locals.contains(var_name) {
                return false;
            }

            // ② pinned（ループ引数など）は outer 扱い
            if scope.pinned.contains(var_name) {
                return true;
            }

            // ③ variable_definitions の情報がある場合だけ、ブロック分布で判断
            if let Some(def_blocks) = scope.variable_definitions.get(var_name) {
                // (Carrier detection logic...)
                // ...
                return false;  // body で定義されている → body-local
            }

            // ④ どこにも出てこない変数 = 関数パラメータ/外側ローカル → OuterLocal
            true  // ← KEY FIX: Default to OuterLocal, not LoopBodyLocal
        }
    }
}

Key Change: Lines 175-184 now default unknown variables to OuterLocal (function parameters).

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Test Results After Fix

Test 1: Simple Function Parameter Loop

File: /tmp/test_jsonparser_simple.hako

Loop Pattern: Pattern 2 (loop with break), using function parameters s and pos

Before Fix:

❌ UnsupportedPattern: Variable 's' and 'pos' incorrectly classified as LoopBodyLocal

After Fix:

✅ [joinir/pattern2] Phase 170-D: Condition variables verified: {"pos", "s", "len"}
⚠️ Different error: Method call `.substring()` not supported in loop body (separate limitation)

Analysis:

• ✅ Function parameters correctly classified: s and pos are now OuterLocal
• ⚠️ New blocker: Method calls in loop body (Pattern 5+ feature)
• Impact: Bug fix works correctly - variable classification is fixed

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Test 2: TrimTest (LoopBodyLocal in Break Condition)

File: local_tests/test_trim_main_pattern.hako

Loop Pattern: Pattern 2, using LoopBodyLocal ch in break condition

Result:

✅ [joinir/pattern2] Phase 170-D: Condition variables verified: {"ch", "end", "start"}
❌ [ERROR] Variable 'ch' not bound in ConditionEnv

Analysis:

• ✅ Correctly rejects LoopBodyLocal: ch is defined inside loop (local ch = ...)
• ✅ Correct error message: "Variable 'ch' not bound" (not misclassified)
• ✅ Expected behavior: Pattern 2 doesn't support LoopBodyLocal in break conditions

Validation: This is the correct rejection - ch should need Pattern 5+ support.

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Test 3: JsonParser Full File

File: tools/hako_shared/json_parser.hako

Result:

❌ [ERROR] Unsupported expression in value context: MethodCall { object: Variable { name: "s" }, method: "length", ... }

Analysis:

• ✅ Variable classification working: No more "variable incorrectly classified" errors
• ⚠️ New blocker: Method calls in loop conditions (s.length())
• Impact: Bug fix successful - JsonParser now hits different limitations (not variable scope bugs)

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Pattern 1-4 Coverage Analysis (After Fix)

✅ Fixed by Bug Fix

Before Fix: X loops incorrectly rejected due to function parameter misclassification

After Fix: These loops now correctly pass variable classification:

• Simple loops using function parameters: ✅ s, pos classified as OuterLocal
• Loops with outer locals: ✅ len, maxLen classified correctly
• Carrier variables: ✅ start, end (header+latch) classified as OuterLocal

⚠️ Remaining Limitations (Not Bug - Missing Features)

Pattern 2 doesn't support:

1. Method calls in loop condition: s.length(), s.substring() → Need Pattern 5+
2. Method calls in loop body: .substring() in break guards → Need Pattern 5+
3. LoopBodyLocal in break conditions: local ch = ...; if ch == ... → Need Pattern 5+

These are legitimate feature gaps, not bugs.

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Verification Commands

# Test 1: Function parameter loop (should pass variable verification)
NYASH_JOINIR_DEBUG=1 NYASH_JOINIR_STRUCTURE_ONLY=1 \
  ./target/release/hakorune /tmp/test_jsonparser_simple.hako 2>&1 | \
  grep "Phase 170-D"

# Expected: Phase 170-D: Condition variables verified: {"pos", "s", "len"}

# Test 2: LoopBodyLocal in break (should correctly reject)
NYASH_JOINIR_DEBUG=1 NYASH_JOINIR_STRUCTURE_ONLY=1 \
  ./target/release/hakorune local_tests/test_trim_main_pattern.hako 2>&1 | \
  grep "Phase 170-D\|Variable 'ch'"

# Expected:
#   Phase 170-D: Condition variables verified: {"ch", "end", "start"}
#   ERROR: Variable 'ch' not bound in ConditionEnv

# Test 3: JsonParser (should pass variable verification, fail on method calls)
NYASH_JOINIR_STRUCTURE_ONLY=1 \
  ./target/release/hakorune tools/hako_shared/json_parser.hako 2>&1 | \
  grep -E "Phase 170-D|MethodCall"

# Expected: Error about MethodCall, not about variable classification

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Impact Assessment

✅ What the Fix Achieves

1. Function parameters work correctly: s, pos in JsonParser methods
2. Carrier variables work correctly: start, end in trim loops
3. Outer locals work correctly: len, maxLen from outer scope
4. Correct rejection: LoopBodyLocal ch properly rejected (not a bug)

⚠️ What Still Needs Work

Pattern 5+ Features (not covered by this fix):

• Method calls in conditions: loop(pos < s.length())
• Method calls in loop body: s.substring(pos, pos+1)
• LoopBodyLocal in break conditions: if ch == " " { break }

Exit Line & Boundary Issues (orthogonal to this fix):

• Some loops fail with ExitLine/Boundary errors
• These are separate architectural issues

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Next Steps

Priority 1: Pattern 5+ Implementation

Target loops:

• _trim loops (LoopBodyLocal ch in break condition)
• _parse_object, _parse_array (method calls in loop body)

Estimated impact: 10-15 additional loops in JsonParser

Priority 2: .hako Rewrite Strategy

For loops with complex method calls:

• Hoist .length() calls to outer locals
• Pre-compute .substring() results outside loop
• Simplify break conditions to use simple comparisons

Example rewrite:

// Before (Pattern 5+ needed)
loop(pos < s.length()) {
  local ch = s.substring(pos, pos+1)
  if ch == "}" { break }
  pos = pos + 1
}

// After (Pattern 2 compatible)
local len = s.length()
loop(pos < len) {
  // Need to avoid method calls in break guard
  // This still requires Pattern 5+ for ch definition
  local ch = s.substring(pos, pos+1)
  if ch == "}" { break }
  pos = pos + 1
}

Priority 3: Coverage Metrics

Run systematic observation:

# Count loops by pattern support
./tools/analyze_joinir_coverage.sh tools/hako_shared/json_parser.hako

# Expected output:
#   Pattern 1: X loops
#   Pattern 2: Y loops (with method call blockers)
#   Pattern 3: Z loops
#   Pattern 4: W loops
#   Unsupported (need Pattern 5+): N loops

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Conclusion

✅ Bug Fix Complete: Function parameters correctly classified as OuterLocal ✅ Verification Successful: Tests demonstrate correct variable classification ✅ Expected Rejections: LoopBodyLocal in break conditions correctly rejected ⚠️ Next Blockers: Method calls in loops (Pattern 5+ features, not bugs)

Overall Impact: Significant progress - variable scope classification is now correct. Remaining errors are legitimate feature gaps, not misclassification bugs.