New lint: precedence_bits, with recent additions to precedence#14115
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llogiq merged 1 commit intorust-lang:masterfrom Jan 30, 2025
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New lint: precedence_bits, with recent additions to precedence#14115llogiq merged 1 commit intorust-lang:masterfrom
precedence_bits, with recent additions to precedence#14115llogiq merged 1 commit intorust-lang:masterfrom
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Commit 2550530 has extended the `precedence` lint to include bitmasking and shift operations. The lint is warn by default, and this generates many hits, especially in embedded or system code, where it is very idiomatic to use expressions such as `1 << 3 | 1 << 5` without parentheses. This commit splits the recent addition into a new lint, which is put into the "restriction" category, while the original one stays in "complexity", because mixing bitmasking and arithmetic operations is less typical.
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Agree. I'll merge this right away without a FCP because I understand that we're reducing a lot of churn, and we want to do that quickly. |
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Mostly cleaning up some more map_ors, but the one big change of note is temporarily allowing the clippy:precedence lint. Previously this lint only applied to arithmetic operations, however a change in 1.85 causes it to apply to bitwise operations as well. This is overly noisy, and unnecessary. And the clippy maintainers agree, as they've since split out this change into a separate lint, precedence_bits, that is allow-by-default. However that split will not be present until 1.86. See rust-lang/rust-clippy#14115 for details on that.
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- Allow clippy::precedence which includes bitmasking and shift operations in Rust 1.85. This behaviour will be reverted in 1.86: rust-lang/rust-clippy#14115.
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- Allow clippy::precedence which includes bitmasking and shift operations in Rust 1.85. This behaviour will be reverted in 1.86: rust-lang/rust-clippy#14115.
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Specifically when rust-lang/rust-clippy#14115 is shipped.
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Specifically when rust-lang/rust-clippy#14115 is shipped.
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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)
|
warning: operator precedence can trip the unwary
--> drivers/gpu/nova-core/vbios.rs:511:17
|
511 | / u32::from(data[29]) << 24
512 | | | u32::from(data[28]) << 16
513 | | | u32::from(data[27]) << 8
| |______________________________________________^
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#precedence
help: consider parenthesizing your expression
|
511 ~ u32::from(data[29]) << 24
512 + | u32::from(data[28]) << 16 | (u32::from(data[27]) << 8)
|
warning: operator precedence can trip the unwary
--> drivers/gpu/nova-core/vbios.rs:511:17
|
511 | / u32::from(data[29]) << 24
512 | | | u32::from(data[28]) << 16
| |_______________________________________________^ help: consider parenthesizing your expression: `(u32::from(data[29]) << 24) | (u32::from(data[28]) << 16)`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#precedence
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 "false positives"
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: rust-lang/rust-clippy#14097 [1]
Link: rust-lang/rust-clippy#14115 [2]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
ojeda
added a commit
to ojeda/linux
that referenced
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Mar 31, 2026
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)
|
warning: operator precedence can trip the unwary
--> drivers/gpu/nova-core/vbios.rs:511:17
|
511 | / u32::from(data[29]) << 24
512 | | | u32::from(data[28]) << 16
513 | | | u32::from(data[27]) << 8
| |______________________________________________^
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#precedence
help: consider parenthesizing your expression
|
511 ~ u32::from(data[29]) << 24
512 + | u32::from(data[28]) << 16 | (u32::from(data[27]) << 8)
|
warning: operator precedence can trip the unwary
--> drivers/gpu/nova-core/vbios.rs:511:17
|
511 | / u32::from(data[29]) << 24
512 | | | u32::from(data[28]) << 16
| |_______________________________________________^ help: consider parenthesizing your expression: `(u32::from(data[29]) << 24) | (u32::from(data[28]) << 16)`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#precedence
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 "false positives"
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: rust-lang/rust-clippy#14097 [1]
Link: rust-lang/rust-clippy#14115 [2]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
ojeda
added a commit
to ojeda/linux
that referenced
this pull request
Apr 1, 2026
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)
|
warning: operator precedence can trip the unwary
--> drivers/gpu/nova-core/vbios.rs:511:17
|
511 | / u32::from(data[29]) << 24
512 | | | u32::from(data[28]) << 16
513 | | | u32::from(data[27]) << 8
| |______________________________________________^
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#precedence
help: consider parenthesizing your expression
|
511 ~ u32::from(data[29]) << 24
512 + | u32::from(data[28]) << 16 | (u32::from(data[27]) << 8)
|
warning: operator precedence can trip the unwary
--> drivers/gpu/nova-core/vbios.rs:511:17
|
511 | / u32::from(data[29]) << 24
512 | | | u32::from(data[28]) << 16
| |_______________________________________________^ help: consider parenthesizing your expression: `(u32::from(data[29]) << 24) | (u32::from(data[28]) << 16)`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#precedence
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 "false positives"
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: rust-lang/rust-clippy#14097 [1]
Link: rust-lang/rust-clippy#14115 [2]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Darksonn
pushed a commit
to Darksonn/linux
that referenced
this pull request
Apr 1, 2026
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)
|
warning: operator precedence can trip the unwary
--> drivers/gpu/nova-core/vbios.rs:511:17
|
511 | / u32::from(data[29]) << 24
512 | | | u32::from(data[28]) << 16
513 | | | u32::from(data[27]) << 8
| |______________________________________________^
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#precedence
help: consider parenthesizing your expression
|
511 ~ u32::from(data[29]) << 24
512 + | u32::from(data[28]) << 16 | (u32::from(data[27]) << 8)
|
warning: operator precedence can trip the unwary
--> drivers/gpu/nova-core/vbios.rs:511:17
|
511 | / u32::from(data[29]) << 24
512 | | | u32::from(data[28]) << 16
| |_______________________________________________^ help: consider parenthesizing your expression: `(u32::from(data[29]) << 24) | (u32::from(data[28]) << 16)`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#precedence
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 "false positives"
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: rust-lang/rust-clippy#14097 [1]
Link: rust-lang/rust-clippy#14115 [2]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://lore.kernel.org/r/20260401114540.30108-34-ojeda@kernel.org
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
ojeda
added a commit
to Rust-for-Linux/linux
that referenced
this pull request
Apr 6, 2026
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: rust-lang/rust-clippy#14097 [1]
Link: rust-lang/rust-clippy#14115 [2]
Link: https://lore.kernel.org/rust-for-linux/DFVDKMMA7KPC.2DN0951H3H55Y@kernel.org/
Reviewed-by: Tamir Duberstein <tamird@kernel.org>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260405235309.418950-34-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
ojeda
added a commit
to Rust-for-Linux/linux
that referenced
this pull request
Apr 7, 2026
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: rust-lang/rust-clippy#14097 [1]
Link: rust-lang/rust-clippy#14115 [2]
Link: https://lore.kernel.org/rust-for-linux/DFVDKMMA7KPC.2DN0951H3H55Y@kernel.org/
Reviewed-by: Tamir Duberstein <tamird@kernel.org>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260405235309.418950-34-ojeda@kernel.org
[ Added paragraph from commit message to comment. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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Commit 2550530 has extended the
precedencelint to include bitmasking and shift operations. The lint is warn by default, and this generates many hits, especially in embedded or system code, where it is very idiomatic to use expressions such as1 << 3 | 1 << 5without parentheses.This commit splits the recent addition into a new lint, which is put into the "restriction" category, while the original one stays in "complexity", because mixing bitmasking and arithmetic operations is less typical.
Fix #14097
changelog: [
precedence_bits]: new lint