diff --git a/lib/Alchemy/Phrasea/Collection/Reference/ArrayCacheCollectionReferenceRepository.php b/lib/Alchemy/Phrasea/Collection/Reference/ArrayCacheCollectionReferenceRepository.php
index 17a9a1d790..7351351e93 100644
--- a/lib/Alchemy/Phrasea/Collection/Reference/ArrayCacheCollectionReferenceRepository.php
+++ b/lib/Alchemy/Phrasea/Collection/Reference/ArrayCacheCollectionReferenceRepository.php
@@ -90,13 +90,9 @@ class ArrayCacheCollectionReferenceRepository implements CollectionReferenceRepo
         return null;
     }
 
-    /**
-     * @param array|null $subset
-     * @return CollectionReference[]
-     */
-    public function findHavingOrderMaster(array $subset = null)
+    public function findHavingOrderMaster(array $baseIdsSubset = null)
     {
-        return $this->repository->findHavingOrderMaster($subset);
+        return $this->repository->findHavingOrderMaster($baseIdsSubset);
     }
 
     /**
diff --git a/lib/Alchemy/Phrasea/Collection/Reference/CollectionReferenceRepository.php b/lib/Alchemy/Phrasea/Collection/Reference/CollectionReferenceRepository.php
index d40e827f76..fdbf7289d1 100644
--- a/lib/Alchemy/Phrasea/Collection/Reference/CollectionReferenceRepository.php
+++ b/lib/Alchemy/Phrasea/Collection/Reference/CollectionReferenceRepository.php
@@ -39,10 +39,10 @@ interface CollectionReferenceRepository
     /**
      * Find Collection references having at least one Order Master
      *
-     * @param array<int>|null $subset Restrict search to a subset of base ids.
+     * @param array<int>|null $baseIdsSubset Restrict search to a subset of base ids.
      * @return CollectionReference[]
      */
-    public function findHavingOrderMaster(array $subset = null);
+    public function findHavingOrderMaster(array $baseIdsSubset = null);
 
     /**
      * @param CollectionReference $reference
diff --git a/lib/Alchemy/Phrasea/Collection/Reference/DbalCollectionReferenceRepository.php b/lib/Alchemy/Phrasea/Collection/Reference/DbalCollectionReferenceRepository.php
index 3713ee0ad1..a67f8cad3d 100644
--- a/lib/Alchemy/Phrasea/Collection/Reference/DbalCollectionReferenceRepository.php
+++ b/lib/Alchemy/Phrasea/Collection/Reference/DbalCollectionReferenceRepository.php
@@ -112,7 +112,7 @@ WHERE base_id = :baseId';
         return null;
     }
 
-    public function findHavingOrderMaster(array $subset = null)
+    public function findHavingOrderMaster(array $baseIdsSubset = null)
     {
         $query = self::$selectQuery
             . ' WHERE EXISTS(SELECT 1 FROM basusr WHERE basusr.order_master = 1 AND basusr.base_id = bas.base_id)';
@@ -120,13 +120,13 @@ WHERE base_id = :baseId';
         $parameters = [];
         $types = [];
 
-        if (null !== $subset) {
-            if (empty($subset)) {
+        if (null !== $baseIdsSubset) {
+            if (empty($baseIdsSubset)) {
                 return [];
             }
 
             $query .= ' AND bas.base_id IN (:subset)';
-            $parameters['subset'] = $subset;
+            $parameters['subset'] = $baseIdsSubset;
             $types['subset'] = Connection::PARAM_INT_ARRAY;
         }