Resume a generator stored in an untyped local

[phall1]

iter.next() was lowered only when the checker's type of the receiver was a generator. Package JavaScript leaves that type as any, so a local that holds a generator became a runtime fence:

method calls like 'iter.next' is not supported yet (SC1090).

The local or global IR type is used when the checker type is not a generator. The identifier is pure, so the receiver is not evaluated twice.

export function collect(iterator) {
  const iter = iterator();
  const out = [];
  while (true) {
    const state = iter.next();
    if (state.done) return out;
    out.push(state.value);
  }
}

function* values(): Generator<number, void, unknown> {
  yield 1;
  yield 2;
  yield 3;
}
console.log(JSON.stringify(collect(() => values())));
// [1,2,3]

Differential test: packages/compiler/test/generator-iterator-next.test.ts. Native stdout, stderr, and exit match Node.

Before the change the native binary printed the SC1090 fence above and did not reach [1,2,3].

Effect's Stream.concat reaches this shape through Channel.fromIterator. The public harness is https://github.com/phall1/effect-scriptc-compat. This patch is the generator receiver check. It does not claim broader Effect parity.

[vercel]

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