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comparison_chain: do not lint on 2 blocks expression #14811

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May 16, 2025
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7 changes: 6 additions & 1 deletion clippy_lints/src/comparison_chain.rs
Original file line number Diff line number Diff line change
Expand Up @@ -75,11 +75,15 @@ impl<'tcx> LateLintPass<'tcx> for ComparisonChain {
}

// Check that there exists at least one explicit else condition
let (conds, _) = if_sequence(expr);
let (conds, blocks) = if_sequence(expr);
if conds.len() < 2 {
return;
}

if blocks.len() < 3 {
return;
}

for cond in conds.windows(2) {
if let (&ExprKind::Binary(ref kind1, lhs1, rhs1), &ExprKind::Binary(ref kind2, lhs2, rhs2)) =
(&cond[0].kind, &cond[1].kind)
Expand Down Expand Up @@ -125,6 +129,7 @@ impl<'tcx> LateLintPass<'tcx> for ComparisonChain {
let ExprKind::Binary(_, lhs, rhs) = conds[0].kind else {
unreachable!();
};

let lhs = Sugg::hir(cx, lhs, "..").maybe_paren();
let rhs = Sugg::hir(cx, rhs, "..").addr();
span_lint_and_sugg(
Expand Down
10 changes: 4 additions & 6 deletions tests/ui/comparison_chain.rs
Original file line number Diff line number Diff line change
Expand Up @@ -12,11 +12,10 @@ fn f(x: u8, y: u8, z: u8) {
a()
}

if x > y {
//~^ comparison_chain

// Ignored: Not all cases are covered
if x < y {
a()
} else if x < y {
} else if x > y {
b()
}

Expand Down Expand Up @@ -123,9 +122,8 @@ fn g(x: f64, y: f64, z: f64) {
}

fn h<T: Ord>(x: T, y: T, z: T) {
// Ignored: Not all cases are covered
if x > y {
//~^ comparison_chain

a()
} else if x < y {
b()
Expand Down
42 changes: 9 additions & 33 deletions tests/ui/comparison_chain.stderr
Original file line number Diff line number Diff line change
@@ -1,32 +1,20 @@
error: `if` chain can be rewritten with `match`
--> tests/ui/comparison_chain.rs:15:5
--> tests/ui/comparison_chain.rs:29:5
|
LL | / if x > y {
LL | |
LL | |
LL | | a()
LL | | } else if x < y {
LL | | b()
... |
LL | | c()
LL | | }
| |_____^ help: consider rewriting the `if` chain with `match`: `match x.cmp(&y) {...}`
|
= note: `-D clippy::comparison-chain` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(clippy::comparison_chain)]`

error: `if` chain can be rewritten with `match`
--> tests/ui/comparison_chain.rs:30:5
|
LL | / if x > y {
LL | |
LL | |
LL | | a()
... |
LL | | c()
LL | | }
| |_____^ help: consider rewriting the `if` chain with `match`: `match x.cmp(&y) {...}`

error: `if` chain can be rewritten with `match`
--> tests/ui/comparison_chain.rs:40:5
--> tests/ui/comparison_chain.rs:39:5
|
LL | / if x > y {
LL | |
Expand All @@ -38,7 +26,7 @@ LL | | }
| |_____^ help: consider rewriting the `if` chain with `match`: `match x.cmp(&y) {...}`

error: `if` chain can be rewritten with `match`
--> tests/ui/comparison_chain.rs:50:5
--> tests/ui/comparison_chain.rs:49:5
|
LL | / if x > 1 {
LL | |
Expand All @@ -50,19 +38,7 @@ LL | | }
| |_____^ help: consider rewriting the `if` chain with `match`: `match x.cmp(&1) {...}`

error: `if` chain can be rewritten with `match`
--> tests/ui/comparison_chain.rs:126:5
|
LL | / if x > y {
LL | |
LL | |
LL | | a()
LL | | } else if x < y {
LL | | b()
LL | | }
| |_____^ help: consider rewriting the `if` chain with `match`: `match x.cmp(&y) {...}`

error: `if` chain can be rewritten with `match`
--> tests/ui/comparison_chain.rs:134:5
--> tests/ui/comparison_chain.rs:132:5
|
LL | / if x > y {
LL | |
Expand All @@ -74,7 +50,7 @@ LL | | }
| |_____^ help: consider rewriting the `if` chain with `match`: `match x.cmp(&y) {...}`

error: `if` chain can be rewritten with `match`
--> tests/ui/comparison_chain.rs:144:5
--> tests/ui/comparison_chain.rs:142:5
|
LL | / if x > y {
LL | |
Expand All @@ -86,7 +62,7 @@ LL | | }
| |_____^ help: consider rewriting the `if` chain with `match`: `match x.cmp(&y) {...}`

error: `if` chain can be rewritten with `match`
--> tests/ui/comparison_chain.rs:251:5
--> tests/ui/comparison_chain.rs:249:5
|
LL | / if x + 1 > y * 2 {
LL | |
Expand All @@ -97,5 +73,5 @@ LL | | "cc"
LL | | }
| |_____^ help: consider rewriting the `if` chain with `match`: `match (x + 1).cmp(&(y * 2)) {...}`

error: aborting due to 8 previous errors
error: aborting due to 6 previous errors