Merge branch '8.x'

Author: GrahamCampbell

Collection.php

@@ -1086,7 +1086,7 @@ public function sort($callback = null)
 
         $callback && is_callable($callback)
             ? uasort($items, $callback)
-            : asort($items, $callback);
+            : asort($items, $callback ?? SORT_REGULAR);
 
         return new static($items);
     }

Enumerable.php

@@ -415,9 +415,9 @@ public function whereNotIn($key, $values, $strict = false);
     public function whereNotInStrict($key, $values);
 
     /**
-     * Filter the items, removing any items that don't match the given type.
+     * Filter the items, removing any items that don't match the given type(s).
      *
-     * @param  string  $type
+     * @param  string|string[]  $type
      * @return static
      */
     public function whereInstanceOf($type);

Traits/EnumeratesValues.php

@@ -669,14 +669,24 @@ public function whereNotInStrict($key, $values)
     }
 
     /**
-     * Filter the items, removing any items that don't match the given type.
+     * Filter the items, removing any items that don't match the given type(s).
      *
-     * @param  string  $type
+     * @param  string|string[]  $type
      * @return static
      */
     public function whereInstanceOf($type)
     {
         return $this->filter(function ($value) use ($type) {
+            if (is_array($type)) {
+                foreach ($type as $classType) {
+                    if ($value instanceof $classType) {
+                        return true;
+                    }
+                }
+
+                return false;
+            }
+
             return $value instanceof $type;
         });
     }