diff --git a/phpunit/code/compact-this-inside-class.php b/phpunit/code/compact-this-inside-class.php
new file mode 100644
index 00000000..72d30c5e
--- /dev/null
+++ b/phpunit/code/compact-this-inside-class.php
@@ -0,0 +1,10 @@
+<?php
+function main() {
+    var_dump(
+        (new class {
+            function test() {
+                return compact('this');
+            }
+        })->test()
+    );
+}
diff --git a/phpunit/code/compact-this-outside-class.php b/phpunit/code/compact-this-outside-class.php
new file mode 100644
index 00000000..9c366c67
--- /dev/null
+++ b/phpunit/code/compact-this-outside-class.php
@@ -0,0 +1,4 @@
+<?php
+function testCompactThisOutsideClass() {
+    var_dump(compact('this'));
+}
diff --git a/phpunit/code/compact_no_this.php b/phpunit/code/compact_no_this.php
new file mode 100644
index 00000000..90bb8e45
--- /dev/null
+++ b/phpunit/code/compact_no_this.php
@@ -0,0 +1,18 @@
+<?php
+function main() {
+
+
+var_dump(
+    (new class {
+        function test(){
+            return (static function(){ return compact('this'); })();
+        }
+    })->test()
+);
+
+var_dump(compact('this'));
+
+var_dump((function(){ return compact('this'); })());
+
+
+}
diff --git a/src/Php/Optimizer/FuncCallOptimizer.php b/src/Php/Optimizer/FuncCallOptimizer.php
index 5cdfbf11..b13baa84 100644
--- a/src/Php/Optimizer/FuncCallOptimizer.php
+++ b/src/Php/Optimizer/FuncCallOptimizer.php
@@ -794,14 +794,19 @@ trait FuncCallOptimizer
                 $this->fatalError($expr, 'The argument of compact function can only be literal string');
             }
             $var = $arg->value->value;
-            if (!$this->hasVar($var)) {
-                $this->errorUndefinedVariable($var);
+            if (!$this->hasVar($var) && $var !== 'this') {
+                $this->fatalError($arg->value, "Undefined variable `{$var}` in compact()");
             }
             if ($this->isSuperGlobal($var)) {
                 $this->fatalError($expr, 'Cannot use super global variable `' . $var . '` in compact function');
             }
 
             $key = $this->getLiteralString($var);
+            if ($var === 'this') {
+                if (empty($this->class)) {
+                    $this->fatalError($expr, 'Cannot use compact("this") outside of class method');
+                }
+            }
             $cVar = $this->escapeVarName($var);
             $list[] = '{' . $key . '.str(), php::Var(' . $cVar . ')}';
         }