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Check tail node in check_links #46269

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Merged
merged 1 commit into from
Nov 26, 2017
Merged

Check tail node in check_links #46269

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7 changes: 7 additions & 0 deletions src/liballoc/linked_list.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1288,6 +1288,8 @@ mod tests {
let mut node_ptr: &Node<T>;
match list.head {
None => {
// tail node should also be None.
assert!(list.tail.is_none());
assert_eq!(0, list.len);
return;
}
Expand All @@ -1314,6 +1316,11 @@ mod tests {
}
}
}

// verify that the tail node points to the last node.
let tail = list.tail.as_ref().expect("some tail node").as_ref();
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Do we need the extra as_ref at the end here?

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@udoprog udoprog Nov 26, 2017 •
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list.tail is an Option<Shared<Node<T>>>. The first as_ref avoids creating a local copy (which would have to be in scope). The second converts the Shared ptr into a reference (through Shared::as_ref), which can then be casted.

So yes unless I'm missing something?

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Oh I see, sorry I hadn't noticed the extra level of indirection in there. Looks like the way you're doing this is about as good as it gets, since Shared::as_ptr returns a *mut T, so you'd have to cast that anyways.

assert_eq!(tail as *const Node<T>, node_ptr as *const Node<T>);
// check that len matches interior links.
assert_eq!(len, list.len);
}
}
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