function* iterateEscapeHintReferences() {
    const escapeHint = globalScope.set.get('$$')
    if (escapeHint) {
      yield* escapeHint.references
    }
    for (const ref of globalScope.through) {
      if (ref.identifier.name === '$$') {
        yield ref
      }
    }
  }
Iterate escape hint reference.
@returns {Iterable<Reference>}