1 files changed, 21 insertions, 17 deletions

diff --git a/lib/compress.js b/lib/compress.js
index 7f1b46e3..ce0fbdd5 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -2487,6 +2487,20 @@ merge(Compressor.prototype, {
         // pass 3: we should drop declarations not in_use
         var tt = new TreeTransformer(
             function before(node, descend, in_list) {
+                var parent = tt.parent();
+                if (drop_vars) {
+                    var sym = assign_as_unused(node);
+                    if (sym instanceof AST_SymbolRef
+                        && !(sym.definition().id in in_use_ids)) {
+                        if (node instanceof AST_Assign) {
+                            return maintain_this_binding(parent, node, node.right.transform(tt));
+                        }
+                        return make_node(AST_Number, node, {
+                            value: 0
+                        });
+                    }
+                }
+                if (scope !== self) return;
                 if (node instanceof AST_Function
                     && node.name
                     && !compressor.option("keep_fnames")) {
@@ -2520,9 +2534,7 @@ merge(Compressor.prototype, {
                         def.eliminated++;
                         return make_node(AST_EmptyStatement, node);
                     }
-                    return node;
                 }
-                var parent = tt.parent();
                 if (node instanceof AST_Definitions && !(parent instanceof AST_ForIn && parent.init === node)) {
                     // place uninitialized names at the start
                     var body = [], head = [], tail = [];
@@ -2602,18 +2614,6 @@ merge(Compressor.prototype, {
                         });
                     }
                 }
-                if (drop_vars) {
-                    var sym = assign_as_unused(node);
-                    if (sym instanceof AST_SymbolRef
-                        && !(sym.definition().id in in_use_ids)) {
-                        if (node instanceof AST_Assign) {
-                            return maintain_this_binding(parent, node, node.right.transform(tt));
-                        }
-                        return make_node(AST_Number, node, {
-                            value: 0
-                        });
-                    }
-                }
                 // certain combination of unused name + side effect leads to:
                 //    https://github.com/mishoo/UglifyJS2/issues/44
                 //    https://github.com/mishoo/UglifyJS2/issues/1830
@@ -2645,8 +2645,13 @@ merge(Compressor.prototype, {
                     }
                     return node;
                 }
-                if (node instanceof AST_Scope && node !== self)
+                if (node instanceof AST_Scope) {
+                    var save_scope = scope;
+                    scope = node;
+                    descend(node, this);
+                    scope = save_scope;
                     return node;
+                }
 
                 function template(sym) {
                     return {
@@ -2662,8 +2667,7 @@ merge(Compressor.prototype, {
 
         function scan_ref_scoped(node, descend) {
             var sym;
-            if (scope === self
-                && (sym = assign_as_unused(node)) instanceof AST_SymbolRef
+            if ((sym = assign_as_unused(node)) instanceof AST_SymbolRef
                 && self.variables.get(sym.name) === sym.definition()) {
                 if (node instanceof AST_Assign) node.right.walk(tw);
                 return true;