diff --git a/src/Error/Error.php b/src/Error/Error.php
index 1060161..e1f526a 100644
--- a/src/Error/Error.php
+++ b/src/Error/Error.php
@@ -271,7 +271,7 @@ class Error extends \Exception implements \JsonSerializable, ClientAware
                 $this->locations = array_filter(
                     array_map(
                         function ($node) {
-                            if ($node->loc) {
+                            if ($node->loc && $node->loc->source) {
                                 return $node->loc->source->getLocation($node->loc->start);
                             }
                         },