Parent: #465 Related: #771, #785, #498
Current boundary
Ordinary-function lowering is now on main: distinct lexical/legacy bindings, whole-CaseBlock initialization, source-order legacy updates, labelled/conditional declarations, repeated captured cells, and exact with-record boundaries. Required-bytecode Annex B function-code witnesses improved from 2/159 to 159/159. Program and suspendable environment-mode declaration planning subsequently landed in #790; both paths now have completed pushed integration.
The shared-analysis extraction also exposed an interpreter bug: grouped destructuring lexical declarations were omitted from Annex B exclusions. For example, eval('let unused, { hidden } = {}; { function hidden() {} }'); typeof hidden returned function instead of undefined. The corrected AST traversal rejects that legacy binding while retaining normal eligible declarations. The shared analyzer and interpreter regression coverage landed in 18f60d8a. Compiler consumption and ordinary frame-mode lowering landed in 81ce8599; environment-mode lowering subsequently landed in #790.
Scope
- Share the exact AST-level Annex B eligibility analysis between interpreter and compiler, preserving parameter/arguments exclusions, lexical ancestors, simple versus destructuring catches, labeled declarations, and function/async/generator distinctions.
- Instantiate block and switch function bindings once per entry in the exact lexical scope; closures and direct eval must retain live identity, including repeated entries.
- Keep sloppy legacy var bindings distinct from block bindings and copy the current lexical value only when the declaration statement is evaluated, with no with-object redirection.
- Preserve ordinary function-body hoisting, duplicate-declaration order, branch-only declarations, TDZ, abrupt completion, debugger ordering, and required-bytecode fail-closed admission.
- Extend forced-tree-walker/required-bytecode, moving-GC, OOM, no-GIL/TSan, and exact Test262 witnesses; record causal admission gains separately from default-tier conformance flips.
Acceptance
- One shared, tested Annex B eligibility model drives interpreter and compiler; secure name membership and bounded allocation remain intact.
- Blocks, switch CaseBlocks, labels/branches, loops, catch/finally, and with scopes preserve exact lexical/legacy identity and source-order updates.
- Required bytecode executes supported ordinary block declarations without fallback; unsupported suspendable capture and disposal boundaries remain explicit.
- Focused, full unit, exact relevant Test262, moving-GC/OOM, no-GIL/TSan, debugger, termination, and threadfuzz evidence is recorded.
- Conventional commits land on main with issue links, exact flips, and no unsupported performance claim.
No source rewriting, eager heap environments for every local, snapshots in place of live lexical cells, speculative execution/replay, broad admission before semantics, or changes to stack/queue/job, Promise, Worker, or Map/Set iterator implementations.
Completed integration
CI run 33113309062 completed successfully on main commit 8a1398ffc04e9e30987f968693667c7271ca3ce1, a descendant containing this implementation. All 53 executed jobs succeeded (unit and TSan-unit shards, Linux no-GIL TSan, functional/no-GIL corpus gates, fuzz profiles, ABI, Wasm, Test262 parallel, and docs); the scheduled-only nightly job was skipped. Together with the measured local evidence in the comments, this completes this issue's acceptance.
Environment-mode declaration implementation: 8d772d15 (#790). Its observed eval-context defects were subsequently fixed and verified in #795 and #797. The separate async native-borrow audit remains open in #791; native stack/queue/job and lifecycle work is not claimed complete.