diff --git a/src/TestDriver.php b/src/TestDriver.php
index 5bbb6c3..956d1eb 100644
--- a/src/TestDriver.php
+++ b/src/TestDriver.php
@@ -381,7 +381,7 @@ public function trace(): string
         for ($i=count($traces)-1; $i>=0; $i--) {
             $trace = $traces[$i];
 
-            if ($trace['file'] ?? null === $current_file) {
+            if (($trace['file'] ?? null) === $current_file) {
                 $selected_trace = $trace;
             }
         }