[PATCH 1/2] kbuild: rust: allow `clippy::uninlined_format_args`

[Miguel Ojeda]

Clippy in Rust 1.88.0 (only) reports [1]:

    warning: variables can be used directly in the `format!` string
       --> rust/macros/module.rs:112:23
        |
    112 |         let content = format!("{param}:{content}", param = param, content = content);
        |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#uninlined_format_args
        = note: `-W clippy::uninlined-format-args` implied by `-W clippy::all`
        = help: to override `-W clippy::all` add `#[allow(clippy::uninlined_format_args)]`
    help: change this to
        |
    112 -         let content = format!("{param}:{content}", param = param, content = content);
    112 +         let content = format!("{param}:{content}");

    warning: variables can be used directly in the `format!` string
       --> rust/macros/module.rs:198:14
        |
    198 |         t => panic!("Unsupported parameter type {}", t),
        |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#uninlined_format_args
        = note: `-W clippy::uninlined-format-args` implied by `-W clippy::all`
        = help: to override `-W clippy::all` add `#[allow(clippy::uninlined_format_args)]`
    help: change this to
        |
    198 -         t => panic!("Unsupported parameter type {}", t),
    198 +         t => panic!("Unsupported parameter type {t}"),
        |

The reason it only triggers in that version is that the lint was moved
from `pedantic` to `style` in Rust 1.88.0 and then back to `pedantic`
in Rust 1.89.0 [2][3].

In the first case, the suggestion is fair and a pure simplification, thus
we will clean it up separately.

To keep the behavior the same across all versions, and since the lint
does not work for all macros (e.g. custom ones like `pr_info!`), disable
it globally.

Cc: stable@xxxxxxxxxxxxxxx # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Link: https://lore.kernel.org/rust-for-linux/CANiq72=drAtf3y_DZ-2o4jb6Az9J3Yj4QYwWnbRui4sm4AJD3Q@xxxxxxxxxxxxxx/ [1]
Link: https://github.com/rust-lang/rust-clippy/pull/15287 [2]
Link: https://github.com/rust-lang/rust-clippy/issues/15151 [3]
Signed-off-by: Miguel Ojeda <ojeda@xxxxxxxxxx>
---
 Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Makefile b/Makefile
index 1a219bf1c771..a63684c36d60 100644
--- a/Makefile
+++ b/Makefile
@@ -494,6 +494,7 @@ export rust_common_flags := --edition=2021 \
 			    -Wclippy::ptr_cast_constness \
 			    -Wclippy::ref_as_ptr \
 			    -Wclippy::undocumented_unsafe_blocks \
+			    -Aclippy::uninlined_format_args \
 			    -Wclippy::unnecessary_safety_comment \
 			    -Wclippy::unnecessary_safety_doc \
 			    -Wrustdoc::missing_crate_level_docs \
-- 
2.53.0