Behavioral regressions behind an unchanged declaration

Index: Known gaps

Status (re-verified 2026-10-09 at 456989f): POLICY_NOTE. case208 ground truth records behavioral_break with truth_scope declared-interface and no detector expected. An L4 definition/declaration restrict replay is an unimplemented enhancement, not a regression.

Catalog case208 (restrict added to a function definition only) breaks a valid overlapping consumer at runtime under GCC and Clang, while the declared interface — everything a binary/header comparison reads — is identical. Ground truth records it as behavioral_break: true with truth_scope: declared-interface; no detector is expected to infer it. An L4 source-ABI replay could see restrict on the definition's parameters and report a definition/declaration contract mismatch; that is not implemented.