diff --git a/phpstan/AssertReturnDynamicFunctionReturnTypeExtension.php b/phpstan/AssertReturnDynamicFunctionReturnTypeExtension.php
index c15fa2d..8e8dab6 100644
--- a/phpstan/AssertReturnDynamicFunctionReturnTypeExtension.php
+++ b/phpstan/AssertReturnDynamicFunctionReturnTypeExtension.php
@@ -9,6 +9,7 @@
 use PHPStan\Analyser\TypeSpecifier;
 use PHPStan\Analyser\TypeSpecifierAwareExtension;
 use PHPStan\Analyser\TypeSpecifierContext;
+use PHPStan\Node\Printer\ExprPrinter;
 use PHPStan\Reflection\FunctionReflection;
 use PHPStan\Type\DynamicFunctionReturnTypeExtension;
 use PHPStan\Type\Type;
@@ -21,6 +22,10 @@ final class AssertReturnDynamicFunctionReturnTypeExtension implements
 {
     private TypeSpecifier $typeSpecifier;
 
+    public function __construct(private ExprPrinter $exprPrinter)
+    {
+    }
+
     public function isFunctionSupported(FunctionReflection $functionReflection): bool
     {
         return $functionReflection->getName() === 'Cdn77\Functions\assert_return';
@@ -42,7 +47,9 @@ public function getTypeFromFunctionCall(
             TypeSpecifierContext::createTruthy(),
         );
 
-        return $specifiedTypes->getSureTypes()['$value'][1] ?? null;
+        $originalExprString = $this->exprPrinter->printExpr($functionCall->getArgs()[0]->value);
+
+        return $specifiedTypes->getSureTypes()[$originalExprString][1] ?? null;
     }
 
     public function setTypeSpecifier(TypeSpecifier $typeSpecifier): void