Starting destructuring.

lib/scope.js

@@ -50,6 +50,7 @@ function SymbolDef(scope, index, orig) {
     this.references = [];
     this.global = false;
     this.mangled_name = null;
+    this.object_destructuring_arg = false;
     this.undeclared = false;
     this.constant = false;
     this.index = index;
@@ -60,6 +61,7 @@ SymbolDef.prototype = {
         if (!options) options = {};
 
         return (this.global && !options.toplevel)
+            || this.object_destructuring_arg
             || this.undeclared
             || (!options.eval && (this.scope.uses_eval || this.scope.uses_with))
             || (options.keep_fnames
@@ -94,6 +96,7 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
     var scope = self.parent_scope = null;
     var defun = null;
     var nesting = 0;
+    var object_destructuring_arg = false;
     var tw = new TreeWalker(function(node, descend){
         if (options.screw_ie8 && node instanceof AST_Catch) {
             var save_scope = scope;
@@ -104,6 +107,12 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
             scope = save_scope;
             return true;
         }
+        if (node instanceof AST_Destructuring && node.is_array === false) {
+            object_destructuring_arg = true;  // These don't nest
+            descend();
+            object_destructuring_arg = false;
+            return true;
+        }
         if (node instanceof AST_Scope) {
             node.init_scope_vars(nesting);
             var save_scope = node.parent_scope = scope;
@@ -127,6 +136,10 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
         if (node instanceof AST_Symbol) {
             node.scope = scope;
         }
+        if (node instanceof AST_SymbolFunarg) {
+            node.object_destructuring_arg = object_destructuring_arg;
+            defun.def_variable(node);
+        }
         if (node instanceof AST_SymbolLambda) {
             defun.def_function(node);
         }
@@ -250,6 +263,7 @@ AST_Scope.DEFMETHOD("def_variable", function(symbol){
     if (!this.variables.has(symbol.name)) {
         def = new SymbolDef(this, this.variables.size(), symbol);
         this.variables.set(symbol.name, def);
+        def.object_destructuring_arg = symbol.object_destructuring_arg;
         def.global = !this.parent_scope;
     } else {
         def = this.variables.get(symbol.name);