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Date: Mon, 17 Mar 2025 12:22:31 +0100
From: Danilo Krummrich <dakr@kernel.org>
To: Tamir Duberstein <tamird@gmail.com>
Cc: Andrew Ballance <andrewjballance@gmail.com>,
	Alice Ryhl <aliceryhl@google.com>, Miguel Ojeda <ojeda@kernel.org>,
	Alex Gaynor <alex.gaynor@gmail.com>,
	Boqun Feng <boqun.feng@gmail.com>, Gary Guo <gary@garyguo.net>,
	=?iso-8859-1?Q?Bj=F6rn?= Roy Baron <bjorn3_gh@protonmail.com>,
	Benno Lossin <benno.lossin@proton.me>,
	Andreas Hindborg <a.hindborg@kernel.org>,
	Trevor Gross <tmgross@umich.edu>, rust-for-linux@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] rust: alloc: add `Vec::dec_len`
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On Sun, Mar 16, 2025 at 07:27:22PM -0400, Tamir Duberstein wrote:
>
> Does this suit?

I think for dec_ref() it is not the safety requrement that justifies the
invariant.

I think it should be something along the lines of:

	// INVARIANT: We drop ownership for all elements within the range
	// `[self.len - count, self.len]`, hence the updated value of `set.len`
	// represents the exact number of elements stored within `self`.

> 
> >         // INVARIANT: By the safety requirements of this method `self.len - count` represents the
> >         // exact number of elements stored within `self`.

Please do not use the email quote mechanism for code snippets, it's confusing
for readers to figure out by whom it has been written.