- isSupportedIndexValue admits func/map/set: the overflow map's RC and trace machinery is already fully type-directed (scr_closure/scr_map adapters, the cycle fixpoint's map rule recursing on the value), and nested index-signature records rode the record kind all along
- the C keyed-read miss trap can now describe Map/Set-typed slots (dynDesc), reachable only through that message — no dynCheck ever expects a container
- SC2006's message and hint name the real value domain (functions, Maps, Sets, RegExps, Promises, ...) and the honest blockers left: symbol keys, dual signatures with unequal value types, and values with no representation at all
- diagnostics fixtures pivot to still-fenced shapes (Uint8Array values, unequal duals, a Date-valued bag); corpus 2558/2559 pin the command-registry and container-table patterns — declared+overflow hybrids, enumeration, delete, registry-capturing cycles, container churn — byte-identical vs Node on both backends
- mapType back-references mint placeholder shapes/unions finalized at frame exit; identity is per checker type, and context-sensitive (generic/mixin) knots stay fenced
- every type walk survives cyclic shape graphs: coinductive JSON/dyn-safety predicates, guarded formatIrType/jsvalLiftable, cycle headers via the existing collector fixpoint on both backends
- JSON.stringify throws V8's byte-exact circular TypeError (hop lines, ellipsis rule); cyclic values crossing into checked-dynamic slots trap instead of hanging
- console.log/util.inspect render <ref *N>/[Circular *N] exactly (SEMANTICS 129 resolved; depth:null lowers) and deepStrictEqual terminates through Node's pair memo
- corpus 2480-2488 green on C, LLVM, and the sanitized RC-audit lane, which proves child->parent cycles collect
Chris Tate