diff --git a/clippy_lints/src/manual_div_ceil.rs b/clippy_lints/src/manual_div_ceil.rs index aa59b047b169..816ca17b3d2d 100644 --- a/clippy_lints/src/manual_div_ceil.rs +++ b/clippy_lints/src/manual_div_ceil.rs @@ -102,12 +102,48 @@ impl<'tcx> LateLintPass<'tcx> for ManualDivCeil { { build_suggestion(cx, expr, add_lhs, div_rhs, &mut applicability); } + + // (x + (Y - 1)) / Y + if inner_op.node == BinOpKind::Add && differ_by_one(inner_rhs, div_rhs) { + build_suggestion(cx, expr, inner_lhs, div_rhs, &mut applicability); + } + + // ((Y - 1) + x) / Y + if inner_op.node == BinOpKind::Add && differ_by_one(inner_lhs, div_rhs) { + build_suggestion(cx, expr, inner_rhs, div_rhs, &mut applicability); + } + + // (x - (-Y - 1)) / Y + if inner_op.node == BinOpKind::Sub + && let ExprKind::Unary(UnOp::Neg, abs_div_rhs) = div_rhs.kind + && differ_by_one(abs_div_rhs, inner_rhs) + { + build_suggestion(cx, expr, inner_lhs, div_rhs, &mut applicability); + } } } extract_msrv_attr!(LateContext); } +/// Checks if two expressions represent non-zero integer literals such that `small_expr + 1 == +/// large_expr`. +fn differ_by_one(small_expr: &Expr<'_>, large_expr: &Expr<'_>) -> bool { + if let ExprKind::Lit(small) = small_expr.kind + && let ExprKind::Lit(large) = large_expr.kind + && let LitKind::Int(s, _) = small.node + && let LitKind::Int(l, _) = large.node + { + Some(l.get()) == s.get().checked_add(1) + } else if let ExprKind::Unary(UnOp::Neg, small_inner_expr) = small_expr.kind + && let ExprKind::Unary(UnOp::Neg, large_inner_expr) = large_expr.kind + { + differ_by_one(large_inner_expr, small_inner_expr) + } else { + false + } +} + fn check_int_ty_and_feature(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool { let expr_ty = cx.typeck_results().expr_ty(expr); match expr_ty.peel_refs().kind() { diff --git a/tests/ui/manual_div_ceil.fixed b/tests/ui/manual_div_ceil.fixed index 1fb1df5b4425..f6eb5a9784ac 100644 --- a/tests/ui/manual_div_ceil.fixed +++ b/tests/ui/manual_div_ceil.fixed @@ -50,3 +50,14 @@ fn issue_13843() { let _ = 1_000_000_u32.div_ceil(6u32); } + +fn issue_13950() { + let x = 33u32; + let _ = x.div_ceil(8); + let _ = x.div_ceil(8); + + let y = -33i32; + let _ = (y + -8) / -7; + let _ = (-8 + y) / -7; + let _ = (y - 8) / -7; +} diff --git a/tests/ui/manual_div_ceil.rs b/tests/ui/manual_div_ceil.rs index 4f6d38f0d145..2f063afe787d 100644 --- a/tests/ui/manual_div_ceil.rs +++ b/tests/ui/manual_div_ceil.rs @@ -50,3 +50,14 @@ fn issue_13843() { let _ = (1_000_000 + 6u32 - 1) / 6u32; } + +fn issue_13950() { + let x = 33u32; + let _ = (x + 7) / 8; + let _ = (7 + x) / 8; + + let y = -33i32; + let _ = (y + -8) / -7; + let _ = (-8 + y) / -7; + let _ = (y - 8) / -7; +} diff --git a/tests/ui/manual_div_ceil.stderr b/tests/ui/manual_div_ceil.stderr index 3d87fe8e0409..0bac5d8ef1c1 100644 --- a/tests/ui/manual_div_ceil.stderr +++ b/tests/ui/manual_div_ceil.stderr @@ -85,5 +85,17 @@ error: manually reimplementing `div_ceil` LL | let _ = (1_000_000 + 6u32 - 1) / 6u32; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `1_000_000_u32.div_ceil(6u32)` -error: aborting due to 14 previous errors +error: manually reimplementing `div_ceil` + --> tests/ui/manual_div_ceil.rs:56:13 + | +LL | let _ = (x + 7) / 8; + | ^^^^^^^^^^^ help: consider using `.div_ceil()`: `x.div_ceil(8)` + +error: manually reimplementing `div_ceil` + --> tests/ui/manual_div_ceil.rs:57:13 + | +LL | let _ = (7 + x) / 8; + | ^^^^^^^^^^^ help: consider using `.div_ceil()`: `x.div_ceil(8)` + +error: aborting due to 16 previous errors diff --git a/tests/ui/manual_div_ceil_with_feature.fixed b/tests/ui/manual_div_ceil_with_feature.fixed index f32b78aa14d0..01c58151bc94 100644 --- a/tests/ui/manual_div_ceil_with_feature.fixed +++ b/tests/ui/manual_div_ceil_with_feature.fixed @@ -50,3 +50,14 @@ fn issue_13843() { let _ = 1_000_000_u32.div_ceil(6u32); } + +fn issue_13950() { + let x = 33u32; + let _ = x.div_ceil(8); + let _ = x.div_ceil(8); + + let y = -33i32; + let _ = y.div_ceil(-7); + let _ = y.div_ceil(-7); + let _ = y.div_ceil(-7); +} diff --git a/tests/ui/manual_div_ceil_with_feature.rs b/tests/ui/manual_div_ceil_with_feature.rs index 54d89fcbd462..048ff401581f 100644 --- a/tests/ui/manual_div_ceil_with_feature.rs +++ b/tests/ui/manual_div_ceil_with_feature.rs @@ -50,3 +50,14 @@ fn issue_13843() { let _ = (1_000_000 + 6u32 - 1) / 6u32; } + +fn issue_13950() { + let x = 33u32; + let _ = (x + 7) / 8; + let _ = (7 + x) / 8; + + let y = -33i32; + let _ = (y + -8) / -7; + let _ = (-8 + y) / -7; + let _ = (y - 8) / -7; +} diff --git a/tests/ui/manual_div_ceil_with_feature.stderr b/tests/ui/manual_div_ceil_with_feature.stderr index c5e8c1a687cd..807cfd82724e 100644 --- a/tests/ui/manual_div_ceil_with_feature.stderr +++ b/tests/ui/manual_div_ceil_with_feature.stderr @@ -109,5 +109,35 @@ error: manually reimplementing `div_ceil` LL | let _ = (1_000_000 + 6u32 - 1) / 6u32; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `1_000_000_u32.div_ceil(6u32)` -error: aborting due to 18 previous errors +error: manually reimplementing `div_ceil` + --> tests/ui/manual_div_ceil_with_feature.rs:56:13 + | +LL | let _ = (x + 7) / 8; + | ^^^^^^^^^^^ help: consider using `.div_ceil()`: `x.div_ceil(8)` + +error: manually reimplementing `div_ceil` + --> tests/ui/manual_div_ceil_with_feature.rs:57:13 + | +LL | let _ = (7 + x) / 8; + | ^^^^^^^^^^^ help: consider using `.div_ceil()`: `x.div_ceil(8)` + +error: manually reimplementing `div_ceil` + --> tests/ui/manual_div_ceil_with_feature.rs:60:13 + | +LL | let _ = (y + -8) / -7; + | ^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `y.div_ceil(-7)` + +error: manually reimplementing `div_ceil` + --> tests/ui/manual_div_ceil_with_feature.rs:61:13 + | +LL | let _ = (-8 + y) / -7; + | ^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `y.div_ceil(-7)` + +error: manually reimplementing `div_ceil` + --> tests/ui/manual_div_ceil_with_feature.rs:62:13 + | +LL | let _ = (y - 8) / -7; + | ^^^^^^^^^^^^ help: consider using `.div_ceil()`: `y.div_ceil(-7)` + +error: aborting due to 23 previous errors