Add IteratorIterator generics

src/Psalm/Internal/Stubs/CoreGenericClasses.php

@@ -96,6 +96,80 @@ interface Iterator extends Traversable {
     public function rewind();
 }
 
+/**
+ * @template-covariant TKey
+ * @template-covariant TValue
+ *
+ * @template-extends Iterator<TKey, TValue>
+ */
+interface OuterIterator extends Iterator {
+    /**
+     * @return Iterator<TKey, TValue>
+     */
+    public function getInnerIterator() : Iterator;
+}
+
+/**
+ * @template-covariant TKey
+ * @template-covariant TValue
+ *
+ * @template-extends OuterIterator<TKey, TValue>
+ */
+class IteratorIterator implements OuterIterator {
+    /**
+     * @return Iterator<TKey, TValue>
+     */
+    public function getInnerIterator() : Iterator {}
+
+    /**
+     * Return the current element
+     * @link http://php.net/manual/en/iterator.current.php
+     *
+     * @return TValue Can return any type.
+     *
+     * @since 5.0.0
+     */
+    public function current() {}
+
+    /**
+     * Move forward to next element
+     * @link http://php.net/manual/en/iterator.next.php
+     *
+     * @return void Any returned value is ignored.
+     *
+     * @since 5.0.0
+     */
+    public function next() {}
+
+    /**
+     * Return the key of the current element
+     * @link http://php.net/manual/en/iterator.key.php
+     *
+     * @return TKey scalar on success, or null on failure.
+     *
+     * @since 5.0.0
+     */
+    public function key() {}
+
+    /**
+     * @return bool The return value will be casted to boolean and then evaluated.
+     *              Returns true on success or false on failure.
+     *
+     * @since 5.0.0
+     */
+    public function valid() {}
+
+    /**
+     * Rewind the Iterator to the first element
+     * @link http://php.net/manual/en/iterator.rewind.php
+     *
+     * @return void Any returned value is ignored.
+     *
+     * @since 5.0.0
+     */
+    public function rewind() {}
+}
+
 /**
  * @template-covariant TKey
  * @template-covariant TValue