From: Miguel Ojeda Date: Sun, 5 Apr 2026 23:53:09 +0000 (+0200) Subject: rust: kbuild: allow `clippy::precedence` for Rust < 1.86.0 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=2e2f8b5a065683f4530ee71363875da1a20f5a7f;p=thirdparty%2Fkernel%2Flinux.git rust: kbuild: allow `clippy::precedence` for Rust < 1.86.0 The Clippy `precedence` lint was extended in Rust 1.85.0 to include bitmasking and shift operations [1]. However, because it generated many hits, in Rust 1.86.0 it was split into a new `precedence_bits` lint which is not enabled by default [2]. In other words, only Rust 1.85 has a different behavior. For instance, it reports: warning: operator precedence can trip the unwary --> drivers/gpu/nova-core/fb/hal/ga100.rs:16:5 | 16 | / u64::from(regs::NV_PFB_NISO_FLUSH_SYSMEM_ADDR::read(bar).adr_39_08()) << FLUSH_SYSMEM_ADDR_SHIFT 17 | | | u64::from(regs::NV_PFB_NISO_FLUSH_SYSMEM_ADDR_HI::read(bar).adr_63_40()) 18 | | << FLUSH_SYSMEM_ADDR_SHIFT_HI | |_________________________________________^ | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#precedence = note: `-W clippy::precedence` implied by `-W clippy::all` = help: to override `-W clippy::all` add `#[allow(clippy::precedence)]` help: consider parenthesizing your expression | 16 ~ (u64::from(regs::NV_PFB_NISO_FLUSH_SYSMEM_ADDR::read(bar).adr_39_08()) << FLUSH_SYSMEM_ADDR_SHIFT) | (u64::from(regs::NV_PFB_NISO_FLUSH_SYSMEM_ADDR_HI::read(bar).adr_63_40()) 17 + << FLUSH_SYSMEM_ADDR_SHIFT_HI) | While so far we try our best to keep all versions Clippy-clean, the minimum (which is now Rust 1.85.0 after the bump) and the latest stable are the most important ones; and this may be considered a "false positive" with respect to the behavior in other versions. Thus allow this lint for this version using the per-version flags mechanism introduced in the previous commit. Link: https://github.com/rust-lang/rust-clippy/issues/14097 [1] Link: https://github.com/rust-lang/rust-clippy/pull/14115 [2] Link: https://lore.kernel.org/rust-for-linux/DFVDKMMA7KPC.2DN0951H3H55Y@kernel.org/ Reviewed-by: Tamir Duberstein Reviewed-by: Gary Guo Link: https://patch.msgid.link/20260405235309.418950-34-ojeda@kernel.org [ Added paragraph from commit message to comment. - Miguel ] Signed-off-by: Miguel Ojeda --- diff --git a/Makefile b/Makefile index a305ae4be5224..a497dba9301c2 100644 --- a/Makefile +++ b/Makefile @@ -838,7 +838,13 @@ export WARN_ON_UNUSED_TRACEPOINTS # Per-version Rust flags. These are like `rust_common_flags`, but may # depend on the Rust compiler version (e.g. using `rustc-min-version`). -rust_common_flags_per_version := +# +# `-Aclippy::precedence`: the lint was extended in Rust 1.85.0 to +# include bitmasking and shift operations. However, because it generated +# many hits, in Rust 1.86.0 it was split into a new `precedence_bits` +# lint which is not enabled by default. +rust_common_flags_per_version := \ + $(if $(call rustc-min-version,108600),,-Aclippy::precedence) rust_common_flags += $(rust_common_flags_per_version) KBUILD_HOSTRUSTFLAGS += $(rust_common_flags_per_version) $(HOSTRUSTFLAGS)