Rustonomicon: Fix bug in implementation of Vec::drain() #28265
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In the last code snippet on the following page there is a bug in the implementation of Vec::drain(). https://doc.rust-lang.org/nightly/nomicon/vec-drain.html ```rust pub fn drain(&mut self) -> Drain<T> { // Oops, setting it to 0 while we still need the old value! self.len = 0; unsafe { Drain { // len is used to create a &[T] from &self here, // so we end up always creating an empty slice. iter: RawValIter::new(&self), vec: PhantomData, } } } ``` A simple test to verify that Drain is broken can be found here: https://play.rust-lang.org/?gist=30f579565e4bbf4836ce&version=nightly And here's one with a fixed implementation: https://play.rust-lang.org/?gist=2ec0c1a6dcf5defd7a53&version=nightly
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| let iter = RawValIter::new(&self); | ||
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| // this is a mem::forget safety thing. If this is forgotten, we just |
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I think it's better to keep saying Drain here instead of this.
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Whoops, guess I copied that from vec-final.
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@bors r+ Thank you! |
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📌 Commit 97dd250 has been approved by |
In the last code snippet on the following page there is a bug in the implementation of Vec::drain(). https://doc.rust-lang.org/nightly/nomicon/vec-drain.html ```rust pub fn drain(&mut self) -> Drain<T> { // Oops, setting it to 0 while we still need the old value! self.len = 0; unsafe { Drain { // len is used to create a &[T] from &self here, // so we end up always creating an empty slice. iter: RawValIter::new(&self), vec: PhantomData, } } } ``` A simple test to verify that Drain is broken can be found here: https://play.rust-lang.org/?gist=30f579565e4bbf4836ce&version=nightly And here's one with a fixed implementation: https://play.rust-lang.org/?gist=2ec0c1a6dcf5defd7a53&version=nightly
In the last code snippet on the following page there is a bug in the
implementation of Vec::drain().
https://doc.rust-lang.org/nightly/nomicon/vec-drain.html
A simple test to verify that Drain is broken can be found here:
https://play.rust-lang.org/?gist=30f579565e4bbf4836ce&version=nightly
And here's one with a fixed implementation:
https://play.rust-lang.org/?gist=2ec0c1a6dcf5defd7a53&version=nightly