https://github.com/mage2pro/core/issues/403

app/code/local/Df/Core/lib/array/other.php

@@ -47,11 +47,16 @@ function dfa_group(array $a, $k = null):array {
 /**
  * 2015-12-30 Преобразует коллекцию или массив в карту.
  * 2024-05-14 "Port `df_index()` from `mage2pro/core`": https://github.com/thehcginstitute-com/m1/issues/600
+ * 2024-06-03
+ * 1) "Use the `iterable` type": https://github.com/mage2pro/core/issues/403
+ * 2) `iterable` is supported by PHP ≥ 7.1: https://3v4l.org/qNX1j
+ * 3) https://php.net/manual/en/language.types.iterable.php
+ * https://3v4l.org/AOWmO
  * @used-by df_mvars()
  * @param string|Closure $k
  * @param Traversable|array(int|string => _DO) $a
  */
-function df_index($k, $a):array {return array_combine(df_column($a, $k), df_ita($a));}
+function df_index($k, iterable $a):array {return array_combine(df_column($a, $k), df_ita($a));}
 
 /**
  * 2016-03-25 http://stackoverflow.com/a/1320156