Babel compiler bug with for..of & System.js module

input.jsx

function* a() {
  yield 1
  yield 2
  yield 3
}

for (let b of a()) {
  console.log(b)
}

output-common.js

"use strict";

var marked0$0 = [a].map(regeneratorRuntime.mark);
function a() {
  return regeneratorRuntime.wrap(function a$(context$1$0) {
    while (1) switch (context$1$0.prev = context$1$0.next) {
      case 0:
        context$1$0.next = 2;
        return 1;

      case 2:
        context$1$0.next = 4;
        return 2;

      case 4:
        context$1$0.next = 6;
        return 3;

      case 6:
      case "end":
        return context$1$0.stop();
    }
  }, marked0$0[0], this);
}

var _iteratorNormalCompletion = true;
var _didIteratorError = false;
var _iteratorError = undefined;

try {
  for (var _iterator = a()[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
    var b = _step.value;

    console.log(b);
  }
} catch (err) {
  _didIteratorError = true;
  _iteratorError = err;
} finally {
  try {
    if (!_iteratorNormalCompletion && _iterator["return"]) {
      _iterator["return"]();
    }
  } finally {
    if (_didIteratorError) {
      throw _iteratorError;
    }
  }
}

output-system.js

System.register([], function (_export) {
  "use strict";

  var marked0$0, _iteratorNormalCompletion, _didIteratorError, _iteratorError, _iterator, _step, b;

  function a() {
    return regeneratorRuntime.wrap(function a$(context$1$0) {
      while (1) switch (context$1$0.prev = context$1$0.next) {
        case 0:
          context$1$0.next = 2;
          return 1;

        case 2:
          context$1$0.next = 4;
          return 2;

        case 4:
          context$1$0.next = 6;
          return 3;

        case 6:
        case "end":
          return context$1$0.stop();
      }
    }, marked0$0[0], this);
  }

  return {
    setters: [],
    execute: function () {
      marked0$0 = [a].map(regeneratorRuntime.mark);
      _iteratorNormalCompletion = true;
      _didIteratorError = false;
      _iteratorError = undefined;

      try {
        for (_iterator; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
          b = _step.value;

          console.log(b);
        }
      } catch (err) {
        _didIteratorError = true;
        _iteratorError = err;
      } finally {
        try {
          if (!_iteratorNormalCompletion && _iterator["return"]) {
            _iterator["return"]();
          }
        } finally {
          if (_didIteratorError) {
            throw _iteratorError;
          }
        }
      }
    }
  };
});