Re: [PATCH v4 1/2] rust: add basic Pin<Vec<T, A>> abstractions

["Benno Lossin" <lossin@kernel.org>]

On Sun Oct 12, 2025 at 4:52 PM CEST, Markus Probst wrote:
> @@ -109,6 +111,21 @@ pub struct Vec<T, A: Allocator> {
>      _p: PhantomData<A>,
>  }
>  
> +/// Extension for Pin<Vec<T, A>>
> +pub trait PinnedVecExt<T> {

Why is this an extension trait? Couldn't we directly implement this on
`Vec<T>` with `self: Pin<&mut Self>`?

---
Cheers,
Benno

> +    /// Pin-initializes P and appends it to the back of the [`Vec`] instance without reallocating.
> +    fn push_pin_init<E: From<PushError<P>>, P: PinInit<T, E>>(&mut self, init: P) -> Result<(), E>;
> +
> +    /// Shortens the vector, setting the length to `len` and drops the removed values.
> +    /// If `len` is greater than or equal to the current length, this does nothing.
> +    ///
> +    /// This has no effect on the capacity and will not allocate.
> +    fn truncate(&mut self, len: usize);
> +
> +    /// Removes the last element from a vector and drops it returning true, or false if it is empty.
> +    fn pop(&mut self) -> bool;
> +}
> +
>  /// Type alias for [`Vec`] with a [`Kmalloc`] allocator.
>  ///
>  /// # Examples