fix corner case in `functions` (#3367)

fixes #3366

2 files changed, 35 insertions, 2 deletions

diff --git a/test/compress/functions.js b/test/compress/functions.js
index c43c17eb..7303b91b 100644
--- a/test/compress/functions.js
+++ b/test/compress/functions.js
@@ -2981,3 +2981,34 @@ issue_3364: {
     }
     expect_stdout: "2"
 }
+
+issue_3366: {
+    options = {
+        functions: true,
+        inline: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            function g() {
+                return function() {};
+            }
+            var a = g();
+            (function() {
+                this && a && console.log("PASS");
+            })();
+        }
+        f();
+    }
+    expect: {
+        (function() {
+            function a() {}
+            (function() {
+                this && a && console.log("PASS");
+            })();
+        })();
+    }
+    expect_stdout: "PASS"
+}
diff --git a/test/sandbox.js b/test/sandbox.js
index 23fb4fc9..396a08f1 100644
--- a/test/sandbox.js
+++ b/test/sandbox.js
@@ -73,8 +73,10 @@ exports.run_code = function(code, reuse) {
         process.stdout.write = original_write;
         if (!reuse || code.indexOf(".prototype") >= 0) {
             context = null;
-        } else for (var key in context) {
-            delete context[key];
+        } else {
+            vm.runInContext(Object.keys(context).map(function(name) {
+                return "delete " + name;
+            }).join("\n"), context);
         }
     }
 };