- lowerRegexLiteral drops the (?<name> fence: patterns and \k<name> backreferences run natively in libregexp, and .groups on exec/match/matchAll results desugars into a compile-time record projection over the honest slice — the checker's own Record<string,string> hybrid with overflow entries in group declaration order — whenever the regex is statically known (literals, const bindings, new RegExp("..."), matchAll rows via for-of bindings, stored drains, spread rows, element access)
- Node's exact shapes: a group-less regex answers .groups === undefined, nullable receivers throw Node's TypeError on the unit arms, ES2025 duplicate names project the participating alternative, and destructuring rides — flat, aliased, and the nested { groups: { year } } pattern — via the groups wrap plus a general overflow read for undeclared keys of index-signature shapes
- scr_put_substitution resolves $<name> against lre_get_groupnames with Node's edge answers: nonexistent and nonparticipating names substitute empty, $< stays literal when the pattern has no named groups, an unterminated $<name stays literal
- s.match(re) also claims a nullable string receiver (the Dict<string> member spelling) through the checked narrow; an untraceable .groups read keeps the SC2020 fence with a hint naming the traceable shapes
- Differential corpus 2604-2607 (both backends, SAN), runtime C substitution/backreference cases, refreshed diagnostics snapshots and surface manifest; corpus 1614's deliberate deferred fence moves to a Proxy wrap now that hybrid record reads compile
- island ('any') arguments at intrinsic/libCall/callValue slots take the validated exit (dynCheck's stance); non-exit-safe slots fence with the slot named, and the boundary pass backstops every jsOp/dynCall/dynInvoke argument so world-mixing sites can never ICE
- a checker-'any' receiver/callee that LOWERED checked-dynamic dispatches to the DOM machinery: ambient-this reads are dynKeyGet, rest-args map/forEach ride the runtime dispatch, dyn callees take dynCall
- Object.entries/values push unit-armed (null | undefined) fields as the null literal; new Set(seed) exits an island-handle seed as a validated copy
- fence-bodied functions emit even when their ABI names an unregistered class, and a run()-end sweep rewrites leftover unregistered-class type slots to the inert f64 placeholder — the clang invalid-C escape closes with the ICE
- RegExp[] compiles (REF elements, both backends; map callbacks returning other unrepresentable kinds meet a named fence), and the C emitter appends program-sized line arrays by loop, not spread (500k-line TUs overflowed the stack)
Chris Tate