## Summary
Eliminates remaining `value_gen.next()` calls from function-context code paths,
unifying all ValueId allocation through `MirBuilder::next_value_id()` SSOT allocator.
## Changes
### 1. Fixed `new_typed_value()` (src/mir/builder.rs:1068)
**Before**: `let id = self.value_gen.next();` (bypasses function context)
**After**: `let id = self.next_value_id();` (respects function context)
This is a public API used in function context, so must use SSOT allocator
to avoid collisions with reserved PHI dsts and function params.
### 2. Fixed test code (src/mir/builder.rs)
**test_shadowing_binding_restore** (lines 1161, 1171):
- Simulates function scope with `push_lexical_scope()`
- Changed to `builder.next_value_id()` for function scope simulation
**test_valueid_binding_parallel_allocation** (lines 1196-1216):
- Tests ValueId/BindingId independence
- Changed to `builder.next_value_id()` with note that Module context fallback preserves test intent
### 3. Verified Module context fallbacks (OK, no change needed)
These already check `current_function.is_some()` and use `value_gen.next()` only as Module context fallback:
- `src/mir/builder/utils.rs:43` - next_value_id() SSOT implementation
- `src/mir/builder/utils.rs:436` - pin_to_slot()
- `src/mir/builder/utils.rs:467` - materialize_local()
- `src/mir/utils/phi_helpers.rs:69` - insert_phi_unified()
## Verification
```bash
rg -n "value_gen\.next\(" src/mir --type rust | grep -v "Module context" | grep -v "//"
# Result: Only comments/docs remain
```
## Acceptance
✅ cargo test --release --lib - 997 passed
✅ phase135_trim_mir_verify.sh - PASS
✅ phase132_exit_phi_parity.sh - 3/3 PASS
✅ All function-context `value_gen.next()` eliminated
## Effect
- **Collision prevention**: No more ValueId collisions between function-level allocations and reserved PHI dsts
- **SSOT compliance**: All ValueId allocation flows through single allocator
- **Contract enforcement**: Phase 135 P1 contract_checks will catch violations immediately
🤖 Generated with Claude Code
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
Added verify_exit_phi_no_collision() to contract_checks.rs for early detection
of ValueId collisions between exit PHIs and other instructions.
Problem detected:
- If exit_phi_builder uses builder.value_gen.next() (module-level) instead of
func.next_value_id() (function-level), ValueIds can collide:
Example:
- bb0: %1 = const 0 (counter init)
- bb3: %1 = phi ... (exit PHI - collision!)
Previous behavior:
- Error only detected at LLVM backend runtime
- Cryptic error: "Cannot overwrite PHI dst=1"
New behavior:
- Panic at Rust compile time (debug build)
- Clear error message with fix suggestion:
"Exit PHI dst %1 collides with instruction in block 0
Fix: Use func.next_value_id() in exit_phi_builder.rs"
Benefits:
- 🔥 Fail-Fast: Catch errors during Rust compilation, not LLVM execution
- 📋 Clear messages: Exact collision point + fix suggestion
- 🧪 Testable: verify_exit_phi_no_collision() can be unit tested
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
