It is showing in the output of the bits! macro and not easy to fix there
(at least not without making the macro more complex).  Disable it for
now.

Link: https://github.com/rust-lang/rust-clippy/issues/15852
Reported-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 rust/Cargo.toml | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/rust/Cargo.toml b/rust/Cargo.toml
index 783e626802c..4f98b2c03d3 100644
--- a/rust/Cargo.toml
+++ b/rust/Cargo.toml
@@ -109,6 +109,9 @@ used_underscore_binding = "deny"
 # nice to have, but cannot be enabled yet
 #wildcard_imports = "deny"   # still have many bindings::* imports
 
+# https://github.com/rust-lang/rust-clippy/issues/15852
+double_parens = "allow"
+
 # these may have false positives
 #option_if_let_else = "deny"
 cognitive_complexity = "deny"
-- 
2.51.0

On Fri, Oct 10, 2025 at 12:12 AM Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> It is showing in the output of the bits! macro and not easy to fix there
> (at least not without making the macro more complex).  Disable it for
> now.
>
> Link: https://github.com/rust-lang/rust-clippy/issues/15852
> Reported-by: Richard Henderson <richard.henderson@linaro.org>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---

How about putting it in the macro expansion instead of globally allowing it?

macro_rules! foo {
    ($a:expr, $b:expr, $c:expr, $d:expr) => {
        #[allow(clippy::double_parens)]
        InterruptMask(((($a.union($b).union($c).union($d))).into_bits()) as u32)
    }
}

Why is the double parenthesis needed here by the way? It's a method chain


>  rust/Cargo.toml | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/rust/Cargo.toml b/rust/Cargo.toml
> index 783e626802c..4f98b2c03d3 100644
> --- a/rust/Cargo.toml
> +++ b/rust/Cargo.toml
> @@ -109,6 +109,9 @@ used_underscore_binding = "deny"
>  # nice to have, but cannot be enabled yet
>  #wildcard_imports = "deny"   # still have many bindings::* imports
>
> +# https://github.com/rust-lang/rust-clippy/issues/15852
> +double_parens = "allow"
> +
>  # these may have false positives
>  #option_if_let_else = "deny"
>  cognitive_complexity = "deny"
> --
> 2.51.0
>
>

On 10/10/25 14:23, Manos Pitsidianakis wrote:
> On Fri, Oct 10, 2025 at 12:12 AM Paolo Bonzini <pbonzini@redhat.com> wrote:
>>
>> It is showing in the output of the bits! macro and not easy to fix there
>> (at least not without making the macro more complex).  Disable it for
>> now.
>>
>> Link: https://github.com/rust-lang/rust-clippy/issues/15852
>> Reported-by: Richard Henderson <richard.henderson@linaro.org>
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>> ---
> 
> How about putting it in the macro expansion instead of globally allowing it?
> 
> macro_rules! foo {
>      ($a:expr, $b:expr, $c:expr, $d:expr) => {
>          #[allow(clippy::double_parens)]
>          InterruptMask(((($a.union($b).union($c).union($d))).into_bits()) as u32)
>      }
> }

Can you do it for procedural macros as well?

> Why is the double parenthesis needed here by the way? It's a method chain
It's just how the macro works, occasionally generating double 
parentheses keeps the parser simple.

Paolo

On Fri, Oct 10, 2025 at 5:12 PM Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> On 10/10/25 14:23, Manos Pitsidianakis wrote:
> > On Fri, Oct 10, 2025 at 12:12 AM Paolo Bonzini <pbonzini@redhat.com> wrote:
> >>
> >> It is showing in the output of the bits! macro and not easy to fix there
> >> (at least not without making the macro more complex).  Disable it for
> >> now.
> >>
> >> Link: https://github.com/rust-lang/rust-clippy/issues/15852
> >> Reported-by: Richard Henderson <richard.henderson@linaro.org>
> >> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> >> ---
> >
> > How about putting it in the macro expansion instead of globally allowing it?
> >
> > macro_rules! foo {
> >      ($a:expr, $b:expr, $c:expr, $d:expr) => {
> >          #[allow(clippy::double_parens)]
> >          InterruptMask(((($a.union($b).union($c).union($d))).into_bits()) as u32)
> >      }
> > }
>
> Can you do it for procedural macros as well?

Of course!

>
> > Why is the double parenthesis needed here by the way? It's a method chain
> It's just how the macro works, occasionally generating double
> parentheses keeps the parser simple.

Makes sense.