support destructuring patterns in rest parameters - fixes #550

lib/6to5/transformation/transform.js

@@ -72,6 +72,7 @@ _.each({
   propertyMethodAssignment:  require("./transformers/es6-property-method-assignment"),
   computedPropertyNames:     require("./transformers/es6-computed-property-names"),
   defaultParameters:         require("./transformers/es6-default-parameters"),
+  restParameters:            require("./transformers/es6-rest-parameters"),
   destructuring:             require("./transformers/es6-destructuring"),
   forOf:                     require("./transformers/es6-for-of"),
   unicodeRegex:              require("./transformers/es6-unicode-regex"),
@@ -84,7 +85,6 @@ _.each({
   _blockHoist:               require("./transformers/_block-hoist"),
 
   generators:                require("./transformers/es6-generators"),
-  restParameters:            require("./transformers/es6-rest-parameters"),
 
   protoToAssign:             require("./transformers/optional-proto-to-assign"),
 

lib/6to5/transformation/transformers/es6-rest-parameters.js

@@ -41,6 +41,22 @@ exports.Function = function (node, parent, scope, context, file) {
     );
   }
 
+  // support patterns
+  if (t.isPattern(rest)) {
+    var pattern = rest;
+    rest = file.generateUidIdentifier("ref", scope);
+
+    // let the destructuring transformer handle this
+    var restDeclar = t.variableDeclaration("var", [
+      t.variableDeclarator(pattern, rest)
+    ]);
+
+    // retain evaluation position
+    restDeclar._blockHoist = node.params.length + 1;
+
+    node.body.body.unshift(restDeclar);
+  }
+
   node.body.body.unshift(
     util.template("rest", {
       ARGUMENTS: argsId,