CoffeeScript-in-CoffeeScript is now able to compile subClass extends superClass

lib/coffee_script/scope.js

@@ -47,7 +47,7 @@
   };
   // Find an available, short, name for a compiler-generated variable.
   Scope.prototype.free_variable = function free_variable() {
-    while (check(this.temp_variable)) {
+    while (this.check(this.temp_variable)) {
       ((this.temp_variable = succ(this.temp_variable)));
     }
     this.variables[this.temp_variable] = 'var';