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/[email protected]/
Reviewed-by: Tamir Duberstein <[email protected]>
Reviewed-by: Gary Guo <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>
---
Makefile | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/Makefile b/Makefile
index a305ae4be522..b8c38aa49cf4 100644
--- a/Makefile
+++ b/Makefile
@@ -838,7 +838,8 @@ 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 :=
+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)
--
2.53.0
