v0.0.191

[0.0.191] - 2026-07-01

Changed

• Codegen type-check-impossible guards now raise CodegenInvariantError ([E699]) (#657, follow-up to #626). The #626 audit classified every return None in vera/codegen/** and vera/wasm/**; #658 converted the 104 user-actionable SILENT_SKIP sites to CodegenSkip ([E602]). This converts the genuine INVARIANT_DEFENSIVE guards — non-forwarding dispatch fall-throughs and shape guards on states the type checker has already rejected — to raise CodegenInvariantError, surfaced at the _compile_fn boundary as an [E699] "internal compiler error, please file a bug" (severity error) instead of a silent skip or a mis-attributed [E602]. 21 sites: 2 in codegen/closures.py, 19 in wasm/operators.py; pinned by tests/test_codegen_invariant_e699.py. Behaviour-preserving — the converted paths are # pragma: no cover (type-check-impossible). A closure-body invariant now propagates to _compile_fn for a single [E699] (rather than being caught in _compile_lifted_closure, which emitted [E699] and returned None so the enclosing function also got a spurious [E602] "closure skipped"); and the quantifier-predicate guard is tightened to require exactly one parameter (so a malformed multi-parameter predicate raises rather than silently using the first).
• Corrected the #626 audit's PROPAGATE premise (#657). The audit assumed #658 made every codegen leaf raise, leaving the PROPAGATE if x is None: return None forwards dead. That is false for the #630 [E615] string-interpolation channel: _translate_interpolated_string records failing segments and returns None, which propagates up and is dropped loudly as [E615] at the _compile_fn boundary. So translate_expr / translate_block still return None reachably, and forwards of them are load-bearing PROPAGATE, preserved — not removed (satisfying the issue's "preserved (still reachable)" criterion). Five operators.py sites the audit had tagged INVARIANT were in fact such forwards and are kept as return None; the inference.py defensive sites are kept as Optional-by-contract. The invariant is now documented in vera/skip.py ("Reachable None via the [E615] channel") and at every preserved forward, so a future cleanup pass can't repeat the mistake (which the test suite caught as an AssertionError in TestE615LoudInterpolationFallthrough630).