diff --git a/src/Php/CompilerBase.php b/src/Php/CompilerBase.php
index a4829813..10cc1248 100644
--- a/src/Php/CompilerBase.php
+++ b/src/Php/CompilerBase.php
@@ -173,7 +173,7 @@ class CompilerBase extends \PhpAot\Core\Translator
     protected string $ldflags = '';
     protected int $floatPrecision = 17;
     protected bool $debug = false;
-    protected bool $formatCode = false;
+    protected bool $formatCode = true;
     protected bool $printBacktraceOnError = false;
     protected bool $noLiteralStrings = false;
     protected bool $noConsole = false;  // Windows: hide console window
@@ -1490,7 +1490,7 @@ class CompilerBase extends \PhpAot\Core\Translator
                 if (!$this->hasVar($var)) {
                     $this->addLocalVar($var, self::TYPE_OBJECT);
                     // TODO 返回值类型是一个接口，只能作为 var 变量，无法作为 TypedObject
-                    if (!$this->hasInterface($rightClass)) {
+                    if (!$this->hasInterface($rightClass) and !$this->isAbstractClass($rightClass)) {
                         $this->addObject($var, $rightClass);
                     }
                 } elseif ($this->isTypedObject($var)) {
@@ -1616,6 +1616,18 @@ class CompilerBase extends \PhpAot\Core\Translator
         return Reflection::isInternalClass($name);
     }
 
+    protected function isAbstractClass(string $name): bool
+    {
+        if ($this->isInternalClass($name)) {
+            return Reflection::isAbstractClass($name);
+        }
+        if ($this->hasClass($name)) {
+            $classDef = $this->getClass($name);
+            return $classDef->isAbstract();
+        }
+        return false;
+    }
+
     protected function isInternalInterface(string $name): bool
     {
         return Reflection::isInternalInterface($name);
@@ -1788,6 +1800,10 @@ class CompilerBase extends \PhpAot\Core\Translator
             } elseif (!$this->isInheritedFrom($objectClass, $returnClass)) {
                 $this->fatalError($v, 'The return type is `' . $returnClass . '`, cannot return an instance of `' . $objectClass . '`');
             }
+            // 把子类当做父类返回时，父类必须是抽象类
+            if ($objectClass !== $returnClass and !$this->isAbstractClass($returnClass)) {
+                $this->fatalError($v, 'When returning a subclass instance as its parent type, the parent class must be abstract');
+            }
         }
 
         $exprCode = $this->convertExprType($expr, $returnType, $type);
diff --git a/src/Php/Entity/ClassDef.php b/src/Php/Entity/ClassDef.php
index 0203bc42..9af717da 100644
--- a/src/Php/Entity/ClassDef.php
+++ b/src/Php/Entity/ClassDef.php
@@ -9,6 +9,7 @@
 namespace PhpAot\Php\Entity;
 
 use PhpAot\Php\Context\FunctionContext;
+use PhpParser\Modifiers;
 use PhpParser\Node\Stmt\Trait_;
 
 class ClassDef extends ClassLikeDef
@@ -91,4 +92,9 @@ class ClassDef extends ClassLikeDef
     {
         return $this->constants[$name];
     }
+
+    public function isAbstract(): bool
+    {
+        return $this->flags & Modifiers::ABSTRACT;
+    }
 }
diff --git a/src/Php/Reflection.php b/src/Php/Reflection.php
index e05dd2c0..863232d1 100644
--- a/src/Php/Reflection.php
+++ b/src/Php/Reflection.php
@@ -187,4 +187,13 @@ class Reflection
         $methodDef = $classRef->getMethod($method);
         return $methodDef->getReturnType() ? $methodDef->getReturnType()->getName() : null;
     }
+
+    public static function isAbstractClass(string $name): bool
+    {
+        $class = self::getClass($name);
+        if (!$class) {
+            return false;
+        }
+        return $class->isAbstract();
+    }
 }
diff --git a/tests/aot/dynamic_call/return-abstract-class.phpt b/tests/aot/dynamic_call/return-abstract-class.phpt
new file mode 100644
index 00000000..7a7ac3da
--- /dev/null
+++ b/tests/aot/dynamic_call/return-abstract-class.phpt
@@ -0,0 +1,30 @@
+--TEST--
+return abstract class
+--FILE--
+<?php
+abstract class Base {
+    abstract public function foo();
+}
+
+class User extends Base {
+    public function foo()
+    {
+        return 'foo';
+    }
+}
+
+class Bar {
+    public function getUser() : Base {
+        return new User();
+    }
+}
+
+function main()
+{
+    $bar = new Bar();
+    $user = $bar->getUser();
+    var_dump($user->foo());
+}
+?>
+--EXPECT--
+string(3) "foo"
\ No newline at end of file
diff --git a/tests/aot/dynamic_call/return-base-class-001.phpt b/tests/aot/dynamic_call/return-base-class-001.phpt
new file mode 100644
index 00000000..81e81fad
--- /dev/null
+++ b/tests/aot/dynamic_call/return-base-class-001.phpt
@@ -0,0 +1,34 @@
+--TEST--
+return abstract class
+--SKIPIF--
+<?php die("skip"); ?>
+--FILE--
+<?php
+class Base {
+    public function foo() {
+        return 'base';
+    }
+}
+
+class User extends Base {
+    public function foo()
+    {
+        return 'user';
+    }
+}
+
+class Bar {
+    public function getUser() : Base {
+        return new User();
+    }
+}
+
+function main()
+{
+    $bar = new Bar();
+    $user = $bar->getUser();
+    var_dump($user->foo());
+}
+?>
+--EXPECT--
+string(3) "foo"
\ No newline at end of file
diff --git a/tests/aot/dynamic_call/return-base-class-002.phpt b/tests/aot/dynamic_call/return-base-class-002.phpt
new file mode 100644
index 00000000..4d6a60d1
--- /dev/null
+++ b/tests/aot/dynamic_call/return-base-class-002.phpt
@@ -0,0 +1,34 @@
+--TEST--
+return abstract class
+--SKIPIF--
+<?php die("skip"); ?>
+--FILE--
+<?php
+class Base {
+    public function test() {
+        return 'base';
+    }
+}
+
+class User extends Base {
+    public function foo()
+    {
+        return 'user';
+    }
+}
+
+class Bar {
+    public function getUser() : Base {
+        return new User();
+    }
+}
+
+function main()
+{
+    $bar = new Bar();
+    $user = $bar->getUser();
+    var_dump($user->foo());
+}
+?>
+--EXPECT--
+string(3) "foo"
\ No newline at end of file