diff --git a/examples/error/undef-var.php b/examples/error/undef-var.php
new file mode 100644
index 00000000..89a4c731
--- /dev/null
+++ b/examples/error/undef-var.php
@@ -0,0 +1,5 @@
+<?php
+function main()
+{
+    var_dump($testVar);
+}
\ No newline at end of file
diff --git a/src/Php/CompilerBase.php b/src/Php/CompilerBase.php
index 86c02e99..5bc86f36 100644
--- a/src/Php/CompilerBase.php
+++ b/src/Php/CompilerBase.php
@@ -705,7 +705,7 @@ class CompilerBase extends \PhpAot\Core\Translator
             return ltrim($funcName, '\\');
         }
         if (isset($this->useFunctions[$funcName])) {
-            return $this->useFunctions[$funcName];
+            return $this->useFunctions[$funcName] . '\\' . $funcName;
         }
         return $funcName;
     }
@@ -4679,7 +4679,8 @@ class CompilerBase extends \PhpAot\Core\Translator
         $code = '';
         foreach ($v2->uses as $use) {
             $id = $this->parseIdentifier($use->name);
-            if ($use->type === Node\Stmt\Use_::TYPE_FUNCTION) {
+            $type = $use->type !== Node\Stmt\Use_::TYPE_UNKNOWN ? $use->type : $v2->type;
+            if ($type === Node\Stmt\Use_::TYPE_FUNCTION) {
                 $lastIndex = strrpos($id, '\\');
                 $fn = substr($id, $lastIndex + 1);
                 $ns = substr($id, 0, $lastIndex);
diff --git a/src/polyfills.php b/src/polyfills.php
index b6bc0556..5b72e83b 100644
--- a/src/polyfills.php
+++ b/src/polyfills.php
@@ -43,3 +43,8 @@ function &refval(&$var)
 {
     return $var;
 }
+
+function any(mixed $var): mixed
+{
+    return $var;
+}
\ No newline at end of file
diff --git a/tests/aot/namespace/use-func.phpt b/tests/aot/namespace/use-func.phpt
new file mode 100644
index 00000000..0bd2d322
--- /dev/null
+++ b/tests/aot/namespace/use-func.phpt
@@ -0,0 +1,20 @@
+--TEST--
+use function
+--FILE--
+<?php
+namespace App\Foo {
+    function bar() {
+        var_dump(__FUNCTION__);
+    }
+}
+
+namespace {
+    use function App\Foo\bar;
+    function main()
+    {
+        bar();
+    }
+}
+?>
+--EXPECT--
+string(11) "App\Foo\bar"
\ No newline at end of file