diff --git a/lib/compress.js b/lib/compress.js
index eb932c77..d7723c00 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -11179,7 +11179,7 @@ Compressor.prototype.compress = function(node) {
         function append_var(decls, expressions, name, value) {
             var def = name.definition();
             if (!scope.var_names().has(name.name)) {
-                if (def.first_decl === name) def.first_decl = null;
+                def.first_decl = null;
                 scope.var_names().set(name.name, true);
                 decls.push(make_node(AST_VarDef, name, {
                     name: name,
diff --git a/test/compress/sandbox.js b/test/compress/sandbox.js
index ac12061c..60d56311 100644
--- a/test/compress/sandbox.js
+++ b/test/compress/sandbox.js
@@ -125,6 +125,7 @@ log_nested: {
 
 timers: {
     options = {
+        evaluate: true,
         reduce_vars: true,
         toplevel: true,
         unused: true,
@@ -132,26 +133,22 @@ timers: {
     input: {
         var count = 0, interval = 1000, duration = 3210;
         var timer = setInterval(function() {
-            console.log(++count);
+            if (!count++) setTimeout(function() {
+                clearInterval(timer);
+                console.log(count <= 4 ? "PASS" : "FAIL");
+            }, duration);
         }, interval);
-        setTimeout(function() {
-            clearInterval(timer);
-        }, duration);
     }
     expect: {
         var count = 0;
         var timer = setInterval(function() {
-            console.log(++count);
+            if (!count++) setTimeout(function() {
+                clearInterval(timer);
+                console.log(count <= 4 ? "PASS" : "FAIL");
+            }, 3210);
         }, 1000);
-        setTimeout(function() {
-            clearInterval(timer);
-        }, 3210);
     }
-    expect_stdout: [
-        "1",
-        "2",
-        "3",
-    ]
+    expect_stdout: "PASS"
     node_version: ">=0.12"
 }
 
diff --git a/test/sandbox.js b/test/sandbox.js
index 0fd9fc2d..71d1e09f 100644
--- a/test/sandbox.js
+++ b/test/sandbox.js
@@ -34,7 +34,8 @@ exports.run_code = semver.satisfies(process.version, "0.8") ? function(code, top
     ].some(function(pattern) {
         return pattern.test(code);
     }) ? run_code_exec : run_code_vm)(code, toplevel, timeout);
-    return stdout.length > 1000 ? stdout.slice(0, 1000) + "…《" + stdout.length + "》" : stdout;
+    var len = typeof stdout == "string" && stdout.length;
+    return len > 1000 ? stdout.slice(0, 1000) + "…《" + len + "》" : stdout;
 };
 exports.same_stdout = semver.satisfies(process.version, "0.12") ? function(expected, actual) {
     if (typeof expected != typeof actual) return false;