The return type is merely documented here, it's not actually enforced. For instance, the IteratorIterator implementation can return Traversable, which would break the interface. Most likely, this is for backwards compatibility with code written before return type hints existed. It's still possible to create your own namespaced OuterIterator interface that extends the global one and add a typehint for this method in there.
OuterIterator::getInnerIterator
(PHP 5 >= 5.1.0, PHP 7, PHP 8)
OuterIterator::getInnerIterator — Returns the inner iterator for the current entry
说明
Returns the inner iterator for the current iterator entry.
参数
此函数没有参数。
返回值
Returns the inner iterator for the current entry if it exists, or null otherwise.
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User Contributed Notes 1 note
Sjakie Pruts ¶
5 years ago
