minor clean up (#4149)

1 files changed, 6 insertions, 6 deletions

diff --git a/lib/scope.js b/lib/scope.js
index ec69eb1b..405f563d 100644
--- a/lib/scope.js
+++ b/lib/scope.js
@@ -335,7 +335,7 @@ AST_Toplevel.DEFMETHOD("resolve", return_this);
 function names_in_use(scope, options) {
     var names = scope.names_in_use;
     if (!names) {
-        scope.names_in_use = names = Object.create(scope.mangled_names || null);
+        scope.names_in_use = names = Object.create(null);
         scope.cname_holes = [];
         var cache = options.cache && options.cache.props;
         scope.enclosed.forEach(function(def) {
@@ -369,7 +369,7 @@ function next_mangled_name(scope, options, def) {
         name = base54(holes[i]);
         if (names[name]) continue;
         holes.splice(i, 1);
-        scope.names_in_use[name] = true;
+        in_use[name] = true;
         return name;
     }
     while (true) {
@@ -378,7 +378,7 @@ function next_mangled_name(scope, options, def) {
         if (!names[name]) break;
         holes.push(scope.cname);
     }
-    scope.names_in_use[name] = true;
+    in_use[name] = true;
     return name;
 }
 
@@ -419,7 +419,7 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
     var lname = -1;
 
     if (options.cache && options.cache.props) {
-        var mangled_names = this.mangled_names = Object.create(null);
+        var mangled_names = names_in_use(this, options);
         options.cache.props.each(function(mangled_name) {
             mangled_names[mangled_name] = true;
         });
@@ -491,7 +491,7 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
 
 AST_Toplevel.DEFMETHOD("find_colliding_names", function(options) {
     var cache = options.cache && options.cache.props;
-    var avoid = Object.create(null);
+    var avoid = Object.create(RESERVED_WORDS);
     options.reserved.forEach(to_avoid);
     this.globals.each(add_def);
     this.walk(new TreeWalker(function(node) {
@@ -528,7 +528,7 @@ AST_Toplevel.DEFMETHOD("expand_names", function(options) {
         var name;
         do {
             name = base54(cname++);
-        } while (avoid[name] || RESERVED_WORDS[name]);
+        } while (avoid[name]);
         return name;
     }