diff --git a/src/Type/Definition/ResolveInfo.php b/src/Type/Definition/ResolveInfo.php
index 75c0070..782168d 100644
--- a/src/Type/Definition/ResolveInfo.php
+++ b/src/Type/Definition/ResolveInfo.php
@@ -136,10 +136,10 @@ class ResolveInfo
                 if (isset($this->fragments[$spreadName])) {
                     /** @var FragmentDefinitionNode $fragment */
                     $fragment = $this->fragments[$spreadName];
-                    $fields += $this->foldSelectionSet($fragment->selectionSet, $descend);
+                    $fields = array_merge_recursive($this->foldSelectionSet($fragment->selectionSet, $descend), $fields);
                 }
             } else if ($selectionNode instanceof InlineFragmentNode) {
-                $fields += $this->foldSelectionSet($selectionNode->selectionSet, $descend);
+                $fields = array_merge_recursive($this->foldSelectionSet($selectionNode->selectionSet, $descend), $fields);
             }
         }