diff --git a/core/modules/system/src/Tests/System/ErrorHandlerTest.php b/core/modules/system/src/Tests/System/ErrorHandlerTest.php
index be3946b..07f2aac 100644
--- a/core/modules/system/src/Tests/System/ErrorHandlerTest.php
+++ b/core/modules/system/src/Tests/System/ErrorHandlerTest.php
@@ -100,7 +100,7 @@ function testErrorHandler() {
     $this->assertErrorMessage($error_warning);
     $this->assertErrorMessage($error_user_notice);
     $this->assertNoRaw('<pre class="backtrace">', 'Did not find pre element with backtrace class.');
-    $this->assertErrorLogged($fatal_error['!message']);
+    $this->assertErrorLogged($fatal_error['@message']);
 
     // Set error reporting to not collect notices.
     $config->set('error_level', ERROR_REPORTING_DISPLAY_SOME)->save();