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[arithmetic_side_effects] Fix #10583 #10585

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Merged
merged 1 commit into from
Apr 2, 2023
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[arithmetic_side_effects] Fix #10583 #10585

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12 changes: 10 additions & 2 deletions clippy_lints/src/operators/arithmetic_side_effects.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -154,10 +154,18 @@ impl ArithmeticSideEffects {
Self::literal_integer(cx, actual_rhs),
) {
(None, None) => false,
(None, Some(n)) | (Some(n), None) => match (&op.node, n) {
(None, Some(n)) => match (&op.node, n) {
// Division and module are always valid if applied to non-zero integers
(hir::BinOpKind::Div | hir::BinOpKind::Rem, local_n) if local_n != 0 => true,
// Addition or subtracting zeros is always a no-op
// Adding or subtracting zeros is always a no-op
(hir::BinOpKind::Add | hir::BinOpKind::Sub, 0)
// Multiplication by 1 or 0 will never overflow
| (hir::BinOpKind::Mul, 0 | 1)
=> true,
_ => false,
},
(Some(n), None) => match (&op.node, n) {
// Adding or subtracting zeros is always a no-op
(hir::BinOpKind::Add | hir::BinOpKind::Sub, 0)
// Multiplication by 1 or 0 will never overflow
| (hir::BinOpKind::Mul, 0 | 1)
Expand Down
4 changes: 4 additions & 0 deletions tests/ui/arithmetic_side_effects.rs
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Expand Up @@ -425,4 +425,8 @@ pub fn integer_arithmetic() {
i ^= i;
}

pub fn issue_10583(a: u16) -> u16 {
10 / a
}

fn main() {}
14 changes: 13 additions & 1 deletion tests/ui/arithmetic_side_effects.stderr
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Original file line number Diff line number Diff line change
Expand Up @@ -576,6 +576,12 @@ error: arithmetic operation that can potentially result in unexpected side-effec
LL | i * 2;
| ^^^^^

error: arithmetic operation that can potentially result in unexpected side-effects
--> $DIR/arithmetic_side_effects.rs:394:5
|
LL | 1 % i / 2;
| ^^^^^

error: arithmetic operation that can potentially result in unexpected side-effects
--> $DIR/arithmetic_side_effects.rs:395:5
|
Expand Down Expand Up @@ -642,5 +648,11 @@ error: arithmetic operation that can potentially result in unexpected side-effec
LL | i %= var2;
| ^^^^^^^^^

error: aborting due to 107 previous errors
error: arithmetic operation that can potentially result in unexpected side-effects
--> $DIR/arithmetic_side_effects.rs:429:5
|
LL | 10 / a
| ^^^^^^

error: aborting due to 109 previous errors