added regression test for issue babel#4943, added async-to-generator/…

…async-default-arguments test

packages/babel-core/test/fixtures/transformation/misc/regression-4943/actual.js

@@ -0,0 +1,7 @@
+function mandatory(paramName) {
+  throw new Error(`Missing parameter: ${paramName}`);
+}
+
+async function foo({ a, b = mandatory("b") }) {
+  return Promise.resolve(b);
+}

packages/babel-core/test/fixtures/transformation/misc/regression-4943/expected.js

@@ -0,0 +1,31 @@
+"use strict";
+
+var foo = function () {
+  var _ref = _asyncToGenerator(regeneratorRuntime.mark(function _callee(_ref2) {
+    var a = _ref2.a,
+        _ref2$b = _ref2.b,
+        b = _ref2$b === undefined ? mandatory("b") : _ref2$b;
+    return regeneratorRuntime.wrap(function _callee$(_context) {
+      while (1) {
+        switch (_context.prev = _context.next) {
+          case 0:
+            return _context.abrupt("return", Promise.resolve(b));
+
+          case 1:
+          case "end":
+            return _context.stop();
+        }
+      }
+    }, _callee, this);
+  }));
+
+  return function foo(_x) {
+    return _ref.apply(this, arguments);
+  };
+}();
+
+function _asyncToGenerator(fn) { return function () { var _args = arguments; var _promiseWrapper = this; return new Promise(function (resolve, reject) { var gen = fn.apply(_promiseWrapper, _args); function step(key, arg) { try { var info = gen[key](arg); var value = info.value; } catch (error) { reject(error); return; } if (info.done) { resolve(value); } else { return Promise.resolve(value).then(function (value) { step("next", value); }, function (err) { step("throw", err); }); } } return step("next"); }); }; }
+
+function mandatory(paramName) {
+  throw new Error("Missing parameter: " + paramName);
+}

packages/babel-core/test/fixtures/transformation/misc/regression-4943/options.json

@@ -0,0 +1,4 @@
+{
+  "plugins": ["transform-async-to-generator"],
+  "presets": ["es2015"]
+}

packages/babel-plugin-transform-async-to-generator/test/fixtures/async-to-generator/async-default-arguments/actual.js

@@ -0,0 +1,7 @@
+function mandatory(paramName) {
+  throw new Error(`Missing parameter: ${paramName}`);
+}
+
+async function foo({ a, b = mandatory("b") }) {
+  return Promise.resolve(b);
+}

packages/babel-plugin-transform-async-to-generator/test/fixtures/async-to-generator/async-default-arguments/expected.js

@@ -0,0 +1,15 @@
+let foo = (() => {
+  var _ref2 = babelHelpers.asyncToGenerator(function* (_ref) {
+    let { a, b = mandatory("b") } = _ref;
+
+    return Promise.resolve(b);
+  });
+
+  return function foo(_x) {
+    return _ref2.apply(this, arguments);
+  };
+})();
+
+function mandatory(paramName) {
+  throw new Error(`Missing parameter: ${paramName}`);
+}