minor

lib/ast.js

@@ -698,9 +698,9 @@ function TreeWalker(callback) {
 TreeWalker.prototype = {
     _visit: function(node, descend) {
         this.stack.push(node);
-        var ret = this.visit(node, function(){
+        var ret = this.visit(node, descend ? function(){
             descend.call(node);
-        });
+        } : noop);
         if (!ret && descend) {
             descend.call(node);
         }

lib/scope.js

@@ -209,6 +209,7 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(){
                 node.thedef = sym;
             }
             node.reference();
+            return true;
         }
     });
     self.walk(tw);
@@ -225,6 +226,10 @@ AST_Scope.DEFMETHOD("init_scope_vars", function(){
     this.cname = -1;          // the current index for mangling functions/variables
 });
 
+AST_Scope.DEFMETHOD("strict", function(){
+    return this.has_directive("use strict");
+});
+
 AST_Lambda.DEFMETHOD("init_scope_vars", function(){
     AST_Scope.prototype.init_scope_vars.call(this);
     this.uses_arguments = false;
@@ -298,6 +303,11 @@ AST_Scope.DEFMETHOD("next_mangled", function(){
     }
 });
 
+AST_Scope.DEFMETHOD("references", function(sym){
+    if (sym instanceof AST_Symbol) sym = sym.definition();
+    return this.enclosed.indexOf(sym) < 0 ? null : sym;
+});
+
 AST_Symbol.DEFMETHOD("unmangleable", function(){
     return this.definition().unmangleable();
 });