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Date:   Wed, 17 May 2023 22:44:39 +0200
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Subject: Re: [PATCH 2/4] rust: macros: refactor generics parsing of
 `#[pin_data]` into its own function
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To:     Benno Lossin <benno.lossin@proton.me>
Cc:     rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org,
        patches@lists.linux.dev, Miguel Ojeda <ojeda@kernel.org>,
        Alex Gaynor <alex.gaynor@gmail.com>,
        Wedson Almeida Filho <wedsonaf@gmail.com>,
        Boqun Feng <boqun.feng@gmail.com>, Gary Guo <gary@garyguo.net>,
        =?UTF-8?Q?Bj=c3=b6rn_Roy_Baron?= <bjorn3_gh@protonmail.com>
References: <20230424081112.99890-1-benno.lossin@proton.me>
 <20230424081112.99890-2-benno.lossin@proton.me>
From:   Alice Ryhl <alice@ryhl.io>
In-Reply-To: <20230424081112.99890-2-benno.lossin@proton.me>
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On 4/24/23 10:11, Benno Lossin wrote:
> Other macros might also want to parse generics. Additionally this makes
> the code easier to read, as the next commit will introduce more code in
> `#[pin_data]`. Also add more comments to explain how parsing generics
> work.
> 
> Signed-off-by: Benno Lossin <benno.lossin@proton.me>

Reviewed-by: Alice Ryhl <aliceryhl@google.com>

> +/// Parses the given `TokenStream` into `Generics` and the rest.
> +///
> +/// The generics are not present in the rest, but a where clause might remain.
> +pub(crate) fn parse_generics(input: TokenStream) -> (Generics, Vec<TokenTree>) {
> +    // `impl_generics`, the declared generics with their bounds.
> +    let mut impl_generics = vec![];
> +    // Only the names of the generics, without any bounds.
> +    let mut ty_generics = vec![];
> +    // Tokens not related to the generics e.g. the `where` token and definition.
> +    let mut rest = vec![];
> +    // The current level of `<`.
> +    let mut nesting = 0;
> +    let mut toks = input.into_iter();
> +    // If we are at the beginning of a generic parameter.
> +    let mut at_start = true;
> +    for tt in &mut toks {
> +        match tt.clone() {

Do you need the call to `clone` here? Not a big deal either way.