From: "Gary Guo" <gary@garyguo.net>
To: "Gary Guo" <gary@garyguo.net>, "Benno Lossin" <lossin@kernel.org>,
"Miguel Ojeda" <ojeda@kernel.org>,
"Boqun Feng" <boqun@kernel.org>,
"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
"Andreas Hindborg" <a.hindborg@kernel.org>,
"Alice Ryhl" <aliceryhl@google.com>,
"Trevor Gross" <tmgross@umich.edu>,
"Danilo Krummrich" <dakr@kernel.org>,
"Daniel Almeida" <daniel.almeida@collabora.com>,
"Tamir Duberstein" <tamird@kernel.org>,
"Alexandre Courbot" <acourbot@nvidia.com>,
"Onur Özkan" <work@onurozkan.dev>
Cc: <rust-for-linux@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] rust: pin-init: internal: pin_data: use HRTB to work around `trivial_bounds` for `Unpin`
Date: Fri, 25 Sep 2026 12:43:27 +0100 [thread overview]
Message-ID: <DLODCZ4H8YOQ.1TVPHD847WAUX@garyguo.net> (raw)
In-Reply-To: <20260922211320.1390159-1-gary@kernel.org>
On Tue Sep 22, 2026 at 10:13 PM BST, Gary Guo wrote:
> From: Gary Guo <gary@garyguo.net>
>
> `#[pin_data]` generates a `Unpin` implementation for the user, which
> requires reasoning using field types. This is rejected by rustc as "trivial
> bounds", which can only be specified using the
> `#![feature(trivial_bounds)]`.
>
> Currently we use an extra lifetime in `__Unpin` to work around this; use
> HRTB to introduce a dummy lifetime can achieve the same, which the
> `Zeroable` implementation already uses.
>
> Unify the `Unpin` impl to also use the same HRTB trick that `Zeroable`
> uses. This produces slightly better error message and slightly shorter
> expansion.
>
> Signed-off-by: Gary Guo <gary@garyguo.net>
Applied to pin-init-next.
Best,
Gary
> ---
> rust/pin-init/internal/src/pin_data.rs | 35 +++++++++-----------------
> rust/pin-init/src/__internal.rs | 16 ------------
> 2 files changed, 12 insertions(+), 39 deletions(-)
prev parent reply other threads:[~2026-09-25 11:43 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-22 21:13 Gary Guo
2026-09-25 11:43 ` Gary Guo [this message]
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