nyash-codex
ee2915a6b2
refactor(mir): Extract VariableContext from MirBuilder (Phase 136 follow-up 5/7)
## Summary
Extracted variable mapping management into dedicated VariableContext struct,
completing step 5 of 7 in the Context Box refactoring plan.
## Changes
- NEW: src/mir/builder/variable_context.rs (VariableContext struct + helpers)
- Modified: src/mir/builder.rs (added variable_ctx field + sync helpers)
- Updated: phase-136-context-box-progress.md (5/7 progress)
## Extracted Fields
- variable_map: BTreeMap<String, ValueId> → variable_ctx.variable_map
## Key Features
- snapshot/restore for if/loop pattern state management
- JoinIR integration: CarrierInfo::from_variable_map()
- ExitLine contract enforcement (carriers in variable_map)
- NYASH_TRACE_VARMAP debug visualization support
## Design Clarity
- BindingContext: String → BindingId (binding identity, survives SSA renaming)
- VariableContext: String → ValueId (current SSA values, block-local)
- Both contexts work together for complete variable management
## Tests
- cargo test --release --lib: 1014/1018 passed (4 pre-existing failures)
- phase135_trim_mir_verify.sh: PASS
- Backward compatibility: 100% maintained (deprecated fields synced)
## Progress
Phase 136 Context Extraction: 5/7 complete (71%)
- ✅ Step 1: TypeContext
- ✅ Step 2: CoreContext
- ✅ Step 3: ScopeContext
- ✅ Step 4: BindingContext
- ✅ Step 5: VariableContext (this commit)
- ⏳ Step 6: MetadataContext
- ⏳ Step 7: CompilationContext
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>