diff options
| -rw-r--r-- | CHANGELOG.md | 1 | ||||
| -rw-r--r-- | clippy_lints/src/declared_lints.rs | 1 | ||||
| -rw-r--r-- | clippy_lints/src/precedence.rs | 68 | ||||
| -rw-r--r-- | tests/ui/precedence.fixed | 8 | ||||
| -rw-r--r-- | tests/ui/precedence.stderr | 26 | ||||
| -rw-r--r-- | tests/ui/precedence_bits.fixed | 35 | ||||
| -rw-r--r-- | tests/ui/precedence_bits.rs | 35 | ||||
| -rw-r--r-- | tests/ui/precedence_bits.stderr | 29 |
8 files changed, 153 insertions, 50 deletions
diff --git a/CHANGELOG.md b/CHANGELOG.md index bc42c07224e..e3352ee0783 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -5954,6 +5954,7 @@ Released 2018-09-13 [`positional_named_format_parameters`]: https://rust-lang.github.io/rust-clippy/master/index.html#positional_named_format_parameters [`possible_missing_comma`]: https://rust-lang.github.io/rust-clippy/master/index.html#possible_missing_comma [`precedence`]: https://rust-lang.github.io/rust-clippy/master/index.html#precedence +[`precedence_bits`]: https://rust-lang.github.io/rust-clippy/master/index.html#precedence_bits [`print_in_format_impl`]: https://rust-lang.github.io/rust-clippy/master/index.html#print_in_format_impl [`print_literal`]: https://rust-lang.github.io/rust-clippy/master/index.html#print_literal [`print_stderr`]: https://rust-lang.github.io/rust-clippy/master/index.html#print_stderr diff --git a/clippy_lints/src/declared_lints.rs b/clippy_lints/src/declared_lints.rs index 86bcf8edd57..179502abcc1 100644 --- a/clippy_lints/src/declared_lints.rs +++ b/clippy_lints/src/declared_lints.rs @@ -626,6 +626,7 @@ pub static LINTS: &[&crate::LintInfo] = &[ crate::permissions_set_readonly_false::PERMISSIONS_SET_READONLY_FALSE_INFO, crate::pointers_in_nomem_asm_block::POINTERS_IN_NOMEM_ASM_BLOCK_INFO, crate::precedence::PRECEDENCE_INFO, + crate::precedence::PRECEDENCE_BITS_INFO, crate::ptr::CMP_NULL_INFO, crate::ptr::INVALID_NULL_PTR_USAGE_INFO, crate::ptr::MUT_FROM_REF_INFO, diff --git a/clippy_lints/src/precedence.rs b/clippy_lints/src/precedence.rs index 421b2b74755..ec6835db897 100644 --- a/clippy_lints/src/precedence.rs +++ b/clippy_lints/src/precedence.rs @@ -3,17 +3,14 @@ use clippy_utils::source::snippet_with_applicability; use rustc_ast::ast::BinOpKind::{Add, BitAnd, BitOr, BitXor, Div, Mul, Rem, Shl, Shr, Sub}; use rustc_ast::ast::{BinOpKind, Expr, ExprKind}; use rustc_errors::Applicability; -use rustc_lint::{EarlyContext, EarlyLintPass}; +use rustc_lint::{EarlyContext, EarlyLintPass, Lint}; use rustc_session::declare_lint_pass; use rustc_span::source_map::Spanned; declare_clippy_lint! { /// ### What it does - /// Checks for operations where precedence may be unclear - /// and suggests to add parentheses. Currently it catches the following: - /// * mixed usage of arithmetic and bit shifting/combining operators without - /// parentheses - /// * mixed usage of bitmasking and bit shifting operators without parentheses + /// Checks for operations where precedence may be unclear and suggests to add parentheses. + /// It catches a mixed usage of arithmetic and bit shifting/combining operators without parentheses /// /// ### Why is this bad? /// Not everyone knows the precedence of those operators by @@ -21,15 +18,32 @@ declare_clippy_lint! { /// code. /// /// ### Example - /// * `1 << 2 + 3` equals 32, while `(1 << 2) + 3` equals 7 - /// * `0x2345 & 0xF000 >> 12` equals 5, while `(0x2345 & 0xF000) >> 12` equals 2 + /// `1 << 2 + 3` equals 32, while `(1 << 2) + 3` equals 7 #[clippy::version = "pre 1.29.0"] pub PRECEDENCE, complexity, "operations where precedence may be unclear" } -declare_lint_pass!(Precedence => [PRECEDENCE]); +declare_clippy_lint! { + /// ### What it does + /// Checks for bit shifting operations combined with bit masking/combining operators + /// and suggest using parentheses. + /// + /// ### Why restrict this? + /// Not everyone knows the precedence of those operators by + /// heart, so expressions like these may trip others trying to reason about the + /// code. + /// + /// ### Example + /// `0x2345 & 0xF000 >> 12` equals 5, while `(0x2345 & 0xF000) >> 12` equals 2 + #[clippy::version = "1.86.0"] + pub PRECEDENCE_BITS, + restriction, + "operations mixing bit shifting with bit combining/masking" +} + +declare_lint_pass!(Precedence => [PRECEDENCE, PRECEDENCE_BITS]); impl EarlyLintPass for Precedence { fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) { @@ -38,10 +52,10 @@ impl EarlyLintPass for Precedence { } if let ExprKind::Binary(Spanned { node: op, .. }, ref left, ref right) = expr.kind { - let span_sugg = |expr: &Expr, sugg, appl| { + let span_sugg = |lint: &'static Lint, expr: &Expr, sugg, appl| { span_lint_and_sugg( cx, - PRECEDENCE, + lint, expr.span, "operator precedence might not be obvious", "consider parenthesizing your expression", @@ -57,37 +71,41 @@ impl EarlyLintPass for Precedence { match (op, get_bin_opt(left), get_bin_opt(right)) { ( BitAnd | BitOr | BitXor, - Some(Shl | Shr | Add | Div | Mul | Rem | Sub), - Some(Shl | Shr | Add | Div | Mul | Rem | Sub), + Some(left_op @ (Shl | Shr | Add | Div | Mul | Rem | Sub)), + Some(right_op @ (Shl | Shr | Add | Div | Mul | Rem | Sub)), ) - | (Shl | Shr, Some(Add | Div | Mul | Rem | Sub), Some(Add | Div | Mul | Rem | Sub)) => { + | ( + Shl | Shr, + Some(left_op @ (Add | Div | Mul | Rem | Sub)), + Some(right_op @ (Add | Div | Mul | Rem | Sub)), + ) => { let sugg = format!( "({}) {} ({})", snippet_with_applicability(cx, left.span, "..", &mut applicability), op.as_str(), snippet_with_applicability(cx, right.span, "..", &mut applicability) ); - span_sugg(expr, sugg, applicability); + span_sugg(lint_for(&[op, left_op, right_op]), expr, sugg, applicability); }, - (BitAnd | BitOr | BitXor, Some(Shl | Shr | Add | Div | Mul | Rem | Sub), _) - | (Shl | Shr, Some(Add | Div | Mul | Rem | Sub), _) => { + (BitAnd | BitOr | BitXor, Some(side_op @ (Shl | Shr | Add | Div | Mul | Rem | Sub)), _) + | (Shl | Shr, Some(side_op @ (Add | Div | Mul | Rem | Sub)), _) => { let sugg = format!( "({}) {} {}", snippet_with_applicability(cx, left.span, "..", &mut applicability), op.as_str(), snippet_with_applicability(cx, right.span, "..", &mut applicability) ); - span_sugg(expr, sugg, applicability); + span_sugg(lint_for(&[op, side_op]), expr, sugg, applicability); }, - (BitAnd | BitOr | BitXor, _, Some(Shl | Shr | Add | Div | Mul | Rem | Sub)) - | (Shl | Shr, _, Some(Add | Div | Mul | Rem | Sub)) => { + (BitAnd | BitOr | BitXor, _, Some(side_op @ (Shl | Shr | Add | Div | Mul | Rem | Sub))) + | (Shl | Shr, _, Some(side_op @ (Add | Div | Mul | Rem | Sub))) => { let sugg = format!( "{} {} ({})", snippet_with_applicability(cx, left.span, "..", &mut applicability), op.as_str(), snippet_with_applicability(cx, right.span, "..", &mut applicability) ); - span_sugg(expr, sugg, applicability); + span_sugg(lint_for(&[op, side_op]), expr, sugg, applicability); }, _ => (), } @@ -106,3 +124,11 @@ fn get_bin_opt(expr: &Expr) -> Option<BinOpKind> { fn is_bit_op(op: BinOpKind) -> bool { matches!(op, BitXor | BitAnd | BitOr | Shl | Shr) } + +fn lint_for(ops: &[BinOpKind]) -> &'static Lint { + if ops.iter().all(|op| is_bit_op(*op)) { + PRECEDENCE_BITS + } else { + PRECEDENCE + } +} diff --git a/tests/ui/precedence.fixed b/tests/ui/precedence.fixed index 9864dd2550b..52144a18bac 100644 --- a/tests/ui/precedence.fixed +++ b/tests/ui/precedence.fixed @@ -20,10 +20,10 @@ fn main() { 1 ^ (1 - 1); 3 | (2 - 1); 3 & (5 - 2); - 0x0F00 & (0x00F0 << 4); - 0x0F00 & (0xF000 >> 4); - (0x0F00 << 1) ^ 3; - (0x0F00 << 1) | 2; + 0x0F00 & 0x00F0 << 4; + 0x0F00 & 0xF000 >> 4; + 0x0F00 << 1 ^ 3; + 0x0F00 << 1 | 2; let b = 3; trip!(b * 8); diff --git a/tests/ui/precedence.stderr b/tests/ui/precedence.stderr index 329422cb8a6..68ad5cb4829 100644 --- a/tests/ui/precedence.stderr +++ b/tests/ui/precedence.stderr @@ -43,29 +43,5 @@ error: operator precedence might not be obvious LL | 3 & 5 - 2; | ^^^^^^^^^ help: consider parenthesizing your expression: `3 & (5 - 2)` -error: operator precedence might not be obvious - --> tests/ui/precedence.rs:23:5 - | -LL | 0x0F00 & 0x00F0 << 4; - | ^^^^^^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `0x0F00 & (0x00F0 << 4)` - -error: operator precedence might not be obvious - --> tests/ui/precedence.rs:24:5 - | -LL | 0x0F00 & 0xF000 >> 4; - | ^^^^^^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `0x0F00 & (0xF000 >> 4)` - -error: operator precedence might not be obvious - --> tests/ui/precedence.rs:25:5 - | -LL | 0x0F00 << 1 ^ 3; - | ^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `(0x0F00 << 1) ^ 3` - -error: operator precedence might not be obvious - --> tests/ui/precedence.rs:26:5 - | -LL | 0x0F00 << 1 | 2; - | ^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `(0x0F00 << 1) | 2` - -error: aborting due to 11 previous errors +error: aborting due to 7 previous errors diff --git a/tests/ui/precedence_bits.fixed b/tests/ui/precedence_bits.fixed new file mode 100644 index 00000000000..82fea0d14e4 --- /dev/null +++ b/tests/ui/precedence_bits.fixed @@ -0,0 +1,35 @@ +#![warn(clippy::precedence_bits)] +#![allow( + unused_must_use, + clippy::no_effect, + clippy::unnecessary_operation, + clippy::precedence +)] +#![allow(clippy::identity_op)] +#![allow(clippy::eq_op)] + +macro_rules! trip { + ($a:expr) => { + match $a & 0b1111_1111u8 { + 0 => println!("a is zero ({})", $a), + _ => println!("a is {}", $a), + } + }; +} + +fn main() { + 1 << 2 + 3; + 1 + 2 << 3; + 4 >> 1 + 1; + 1 + 3 >> 2; + 1 ^ 1 - 1; + 3 | 2 - 1; + 3 & 5 - 2; + 0x0F00 & (0x00F0 << 4); + 0x0F00 & (0xF000 >> 4); + (0x0F00 << 1) ^ 3; + (0x0F00 << 1) | 2; + + let b = 3; + trip!(b * 8); +} diff --git a/tests/ui/precedence_bits.rs b/tests/ui/precedence_bits.rs new file mode 100644 index 00000000000..9b353308b6e --- /dev/null +++ b/tests/ui/precedence_bits.rs @@ -0,0 +1,35 @@ +#![warn(clippy::precedence_bits)] +#![allow( + unused_must_use, + clippy::no_effect, + clippy::unnecessary_operation, + clippy::precedence +)] +#![allow(clippy::identity_op)] +#![allow(clippy::eq_op)] + +macro_rules! trip { + ($a:expr) => { + match $a & 0b1111_1111u8 { + 0 => println!("a is zero ({})", $a), + _ => println!("a is {}", $a), + } + }; +} + +fn main() { + 1 << 2 + 3; + 1 + 2 << 3; + 4 >> 1 + 1; + 1 + 3 >> 2; + 1 ^ 1 - 1; + 3 | 2 - 1; + 3 & 5 - 2; + 0x0F00 & 0x00F0 << 4; + 0x0F00 & 0xF000 >> 4; + 0x0F00 << 1 ^ 3; + 0x0F00 << 1 | 2; + + let b = 3; + trip!(b * 8); +} diff --git a/tests/ui/precedence_bits.stderr b/tests/ui/precedence_bits.stderr new file mode 100644 index 00000000000..f468186b363 --- /dev/null +++ b/tests/ui/precedence_bits.stderr @@ -0,0 +1,29 @@ +error: operator precedence might not be obvious + --> tests/ui/precedence_bits.rs:28:5 + | +LL | 0x0F00 & 0x00F0 << 4; + | ^^^^^^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `0x0F00 & (0x00F0 << 4)` + | + = note: `-D clippy::precedence-bits` implied by `-D warnings` + = help: to override `-D warnings` add `#[allow(clippy::precedence_bits)]` + +error: operator precedence might not be obvious + --> tests/ui/precedence_bits.rs:29:5 + | +LL | 0x0F00 & 0xF000 >> 4; + | ^^^^^^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `0x0F00 & (0xF000 >> 4)` + +error: operator precedence might not be obvious + --> tests/ui/precedence_bits.rs:30:5 + | +LL | 0x0F00 << 1 ^ 3; + | ^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `(0x0F00 << 1) ^ 3` + +error: operator precedence might not be obvious + --> tests/ui/precedence_bits.rs:31:5 + | +LL | 0x0F00 << 1 | 2; + | ^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `(0x0F00 << 1) | 2` + +error: aborting due to 4 previous errors + |