diff --git a/examples/assign_cmp.php b/examples/assign_cmp.php
index 97e9e4e6..573b4cc9 100644
--- a/examples/assign_cmp.php
+++ b/examples/assign_cmp.php
@@ -1,28 +1,4 @@
 <?php
-
-class std
-{
-    static function int(int $value): int
-    {
-        return $value;
-    }
-
-    static function float(float $value):  float
-    {
-        return $value;
-    }
-
-    static function bool(bool $value): bool
-    {
-        return $value;
-    }
-
-    static function string(string $str): resource
-    {
-        return fopen('php://stdin', 'r');
-    }
-}
-
 function main()
 {
     $a = std::int(100);
diff --git a/examples/micro_bench.php b/examples/micro_bench.php
index a14d629c..3ccf990c 100644
--- a/examples/micro_bench.php
+++ b/examples/micro_bench.php
@@ -1,14 +1,17 @@
 <?php
+declare(strict_types=1);
+
+use native_types;
 
 function hallo() {
 }
 
-function simpleucall($n) {
+function simpleucall(int $n) {
   for ($i = 0; $i < $n; $i++)
     hallo();
 }
 
-function simpleudcall($n) {
+function simpleudcall(int $n) {
   for ($i = 0; $i < $n; $i++)
     hallo2();
 }
@@ -16,11 +19,15 @@ function simpleudcall($n) {
 function hallo2() {
 }
 
-function simpleicall($n)
+function simpleicall(int $n)
 {
+//    $array = [new ArrayObject()];
+//    $o = $array[0];
+    $o = new stdClass();
     for ($i = 0; $i < $n; $i++) {
 //        $ret = function_exists('hallo');
-        $ret = class_exists('Foo2');
+//        $ret = class_exists('Foo2');
+        $ret = get_class($o);
     }
 }
 
diff --git a/examples/str_byte.php b/examples/str_byte.php
new file mode 100644
index 00000000..6f936e07
--- /dev/null
+++ b/examples/str_byte.php
@@ -0,0 +1,7 @@
+<?php
+function main()
+{
+    $str = "hello world";
+    $str[2] = "$";
+    var_dump($str);
+}
diff --git a/src/Php/CompilerBase.php b/src/Php/CompilerBase.php
index be2a673f..d0ec6159 100644
--- a/src/Php/CompilerBase.php
+++ b/src/Php/CompilerBase.php
@@ -241,11 +241,11 @@ class CompilerBase extends \PhpAot\Core\Translator
     ];
     protected array $globalVars = [];
     protected bool $strictTypes = false;
+    protected bool $nativeTypes = false;
     protected string $rootPath;
     protected string $buildDir;
     protected int $debugLine = 0;
     protected CLImate $climate;
-    protected bool $defaultNativeType = true;
     protected bool $stubFile = false;
     protected bool $enableProfiler = false;
     protected bool $forTest = false;
@@ -612,11 +612,12 @@ class CompilerBase extends \PhpAot\Core\Translator
 
     protected function resetFile(): void
     {
-        $this->indentLevel            = 0;
-        $this->strictTypes            = false;
-        $this->classesDefineInFile    = [];
+        $this->indentLevel = 0;
+        $this->strictTypes = false;
+        $this->nativeTypes = false;
+        $this->classesDefineInFile = [];
         $this->interfacesDefineInFile = [];
-        $this->functionDefineInFile   = [];
+        $this->functionDefineInFile = [];
     }
 
     protected function resetNamespace(): void
@@ -1307,7 +1308,7 @@ class CompilerBase extends \PhpAot\Core\Translator
         return $this->parseAssignFinally($left, $right);
     }
 
-    protected function parseAssignFinally(Node\Expr $left, Node\Expr $right): string
+    protected function parseAssignFinally(Expr $left, Expr $right): string
     {
         if ($left instanceof Expr\List_) {
             $items = $left->items;
@@ -3392,7 +3393,7 @@ class CompilerBase extends \PhpAot\Core\Translator
      */
     protected function getNativeType(string $type): string
     {
-        return $this->defaultNativeType ? $type : self::TYPE_VAR;
+        return $this->nativeTypes ? $type : self::TYPE_VAR;
     }
 
     protected function detectConstType($expr): string
@@ -4018,11 +4019,6 @@ class CompilerBase extends \PhpAot\Core\Translator
 
     /**
      * @param NodeAbstract $expr 仅用于输出错误日志
-     * @param string $property
-     * @param string $class
-     * @param string $namespace
-     * @param bool $static
-     * @return string|null
      */
     protected function findNativeProperty(NodeAbstract $expr, string $property, string $class, string $namespace = '', bool $static = false): ?string
     {
@@ -4320,7 +4316,7 @@ class CompilerBase extends \PhpAot\Core\Translator
     {
         $declares = $v->declares;
         foreach ($declares as $declare) {
-            $key   = $this->parseIdentifier($declare->key);
+            $key = $this->parseIdentifier($declare->key);
             $value = $this->parseIdentifier($declare->value);
             if ($key === 'ticks') {
                 $this->fatalError($v, 'declare(ticks=1) is not supported');
@@ -4328,8 +4324,11 @@ class CompilerBase extends \PhpAot\Core\Translator
                 if (strtolower($value) !== 'utf-8') {
                     $this->fatalError($v, 'declare(encoding="' . $value . '") is not supported, only UTF-8 is supported');
                 }
+            } elseif ($key === 'strict_types') {
+                $this->strictTypes = boolval(intval($value));
+            } else {
+                $this->fatalError($v, 'declare(' . $key . '=' . $value . ') is not supported');
             }
-            $this->strictTypes = boolval(intval($value));
         }
     }
 
@@ -4340,14 +4339,18 @@ class CompilerBase extends \PhpAot\Core\Translator
             $id = $this->parseIdentifier($use->name);
             if ($use->type === Node\Stmt\Use_::TYPE_FUNCTION) {
                 $rpos = strrpos($id, '\\');
-                $fn   = substr($id, $rpos + 1);
-                $ns   = substr($id, 0, $rpos);
+                $fn = substr($id, $rpos + 1);
+                $ns = substr($id, 0, $rpos);
                 // fn => namespace
                 $this->useFunctions[$fn] = $ns;
             } else {
-                $this->useNamespaces[] = $id;
-                if ($use->alias) {
-                    $this->useAliases[$use->alias->toString()] = $id;
+                if ($id === 'native_types') {
+                    $this->nativeTypes = true;
+                } else {
+                    $this->useNamespaces[] = $id;
+                    if ($use->alias) {
+                        $this->useAliases[$use->alias->toString()] = $id;
+                    }
                 }
             }
         }
diff --git a/src/functions.php b/src/functions.php
index 7d2f371d..518db764 100644
--- a/src/functions.php
+++ b/src/functions.php
@@ -1,11 +1,17 @@
 <?php
+/**
+ * This file is part of Swoole-Compiler(AOT).
+ *
+ * @link     https://www.swoole.com/
+ * @contact  service@swoole.com
+ */
 
 use PhpAot\Core\Translator;
 use PhpAot\Php\Exception\Unsupported;
 
 function abort($v)
 {
-    /**
+    /*
      * @var $translator Translator
      */
     global $translator;
@@ -38,12 +44,11 @@ function if_not_empty_debug($if_expr, $v)
     }
 }
 
-
 function debug()
 {
-    foreach(func_get_args() as $arg) {
+    foreach (func_get_args() as $arg) {
         var_dump($arg);
     }
     debug_print_backtrace();
     exit;
-}
\ No newline at end of file
+}
diff --git a/src/polyfills.php b/src/polyfills.php
new file mode 100644
index 00000000..5fc69854
--- /dev/null
+++ b/src/polyfills.php
@@ -0,0 +1,40 @@
+<?php
+/**
+ * This file is part of Swoole-Compiler(AOT).
+ *
+ * @link     https://www.swoole.com/
+ * @contact  service@swoole.com
+ */
+
+class native_types
+{
+    public const type_int = 'int';
+    public const type_float = 'float';
+    public const type_bool = 'bool';
+}
+
+class std
+{
+    public static function int(mixed $value): int
+    {
+        return intval($value);
+    }
+
+    public static function float(mixed $value): float
+    {
+        return floatval($value);
+    }
+
+    public static function bool(mixed $value): bool
+    {
+        return boolval($value);
+    }
+}
+
+function objval(mixed $obj, string $class): object
+{
+    if ($obj instanceof $class) {
+        return $obj;
+    }
+    throw new Exception('Invalid object type');
+}