Phase 72 investigates whether PHI dst ValueIds adhere to reserved region [0-99].
Conclusion: Current system is stable but relies on accidental non-overlap,
NOT architectural enforcement.
Recommendation: Do NOT strengthen verifier. PHI dst allocated by MirBuilder
(separate from JoinValueSpace reserved contract). Full fix deferred to Phase 73+.
Changes:
- verify_phi_reserved.rs: New observation infrastructure (debug-only)
- phase72-phi-reserved-observation.md: Detailed findings + risk assessment
- PHASE_72_SUMMARY.md: Executive summary
- loop_header_phi_builder.rs: Debug observation hooks
- phase72_phi_observation.rs: Unit tests (6/6 PASS)
Tests: lib 950/950 PASS (no regressions)
Architecture: No production impact (debug-only, feature-gated)
🤖 Generated with Claude Code
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
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