forced closure on super classes - fixes #339

lib/6to5/transformation/transformers/es6-classes.js

@@ -21,7 +21,7 @@ exports.ClassDeclaration = function (node, parent, file, scope) {
       });
       return t.assignmentExpression("=", node.id, newNode);
     } else {
-      // likely has a PrivateDeclaration etc
+      // has a super class or PrivateDeclaration etc
       return t.variableDeclaration("let", [
         t.variableDeclarator(node.id, newNode)
       ]);
@@ -85,7 +85,8 @@ Class.prototype.run = function () {
 
   //
 
-  if (superName && t.isDynamic(superName)) {
+  if (superName) {
+    this.closure = true;
     // so we're only evaluating it once
     var superRefName = "super";
     if (className) superRefName = className.name + "Super";
@@ -95,13 +96,8 @@ Class.prototype.run = function () {
       t.variableDeclarator(superRef, superName)
     ]));
     superName = superRef;
-  }
 
-  this.superName = superName;
-
-  //
-
-  if (superName) {
+    this.superName = superName;
     body.push(t.expressionStatement(t.callExpression(file.addDeclaration("inherits"), [className, superName])));
   }