add proper ordering to function param logic - fixes #549

test/fixtures/transformation/es6-default-parameters/destructuring/exec.js

@@ -0,0 +1,19 @@
+function required(msg) {
+  throw new Error(msg);
+}
+
+function sum(
+  { arr = required('arr is required') } = { arr: arr = [] },
+  length = arr.length
+) {
+  let i = 0;
+  let acc = 0;
+  for (let item of arr) {
+    if (i >= length) return acc;
+    acc += item;
+    i++;
+  }
+  return acc;
+}
+
+assert.equal(sum({arr:[1,2]}), 3);