fix: #776 — implicit-return functions now produce undefined, not 0#786
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A function that falls off the end without an explicit `return` was emitting `ret double 0.0`, which under NaN-boxing is the number 0 — not `undefined` (TAG_UNDEFINED = 0x7FFC_0000_0000_0001). Code like `f() === undefined` or `typeof f()` therefore disagreed with JS semantics. Replace every implicit-return / bare-`return;` site with the NaN-boxed TAG_UNDEFINED literal (sync + async, regular functions, closures, methods, static methods). Async epilogues also resolve the promise with `undefined` instead of `0`. With the bug fixed, the class-decorator return-value guard added in PR #754 can be tightened from `typeof ret === "function"` to `ret !== undefined`, catching primitive and plain-object replacement returns as well. Workaround comment dropped, error message generalized, parity expectation updated to match.
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Summary
returnwere emittingret double 0.0in LLVM IR. In Perry's NaN-boxing scheme,0.0is the number 0, notundefined(TAG_UNDEFINED = 0x7FFC_0000_0000_0001). User code that didf() === undefined,typeof f(), orconsole.log(f())against an implicit-return function gotfalse/"number"/0instead of the JS-correcttrue/"undefined"/undefined.return;site: regular functions, closures, methods, static methods (sync + async). Async paths also now resolve the promise withundefined, not0.typeof ret === "function"toret !== undefined, removed the workaround comment, and updated the error message. The previous narrow check only caught function/class replacements; primitive or object returns were silently discarded.Test plan
function bare() {} ; console.log(bare() === undefined, typeof bare(), bare())→true undefined undefined@Injectable(no-return decorator) still works@ReturnsFn/@ReturnsObjdecorators now throw TypeErrormainbaseline at 331)