diff options
| -rw-r--r-- | clippy_lints/src/identity_op.rs | 37 | ||||
| -rw-r--r-- | tests/ui/identity_op.rs | 6 | ||||
| -rw-r--r-- | tests/ui/identity_op.stderr | 20 | ||||
| -rw-r--r-- | tests/ui/modulo_arithmetic_integral_const.rs | 7 | ||||
| -rw-r--r-- | tests/ui/modulo_arithmetic_integral_const.stderr | 34 |
5 files changed, 75 insertions, 29 deletions
diff --git a/clippy_lints/src/identity_op.rs b/clippy_lints/src/identity_op.rs index f824f20ca40..0b1ab4dfa5a 100644 --- a/clippy_lints/src/identity_op.rs +++ b/clippy_lints/src/identity_op.rs @@ -5,7 +5,7 @@ use rustc_middle::ty; use rustc_session::{declare_lint_pass, declare_tool_lint}; use rustc_span::source_map::Span; -use clippy_utils::consts::{constant_simple, Constant}; +use clippy_utils::consts::{constant_full_int, constant_simple, Constant, FullInt}; use clippy_utils::diagnostics::span_lint; use clippy_utils::{clip, unsext}; @@ -54,6 +54,7 @@ impl<'tcx> LateLintPass<'tcx> for IdentityOp { check(cx, left, -1, e.span, right.span); check(cx, right, -1, e.span, left.span); }, + BinOpKind::Rem => check_modulo(cx, left, right, e.span, left.span), _ => (), } } @@ -70,6 +71,18 @@ fn is_allowed(cx: &LateContext<'_>, cmp: BinOp, left: &Expr<'_>, right: &Expr<'_ && constant_simple(cx, cx.typeck_results(), left) == Some(Constant::Int(1))) } +fn check_modulo(cx: &LateContext<'_>, left: &Expr<'_>, right: &Expr<'_>, span: Span, arg: Span) { + let lhs_const = constant_full_int(cx, cx.typeck_results(), left); + let rhs_const = constant_full_int(cx, cx.typeck_results(), right); + if match (lhs_const, rhs_const) { + (Some(FullInt::S(lv)), Some(FullInt::S(rv))) => lv.abs() < rv, + (Some(FullInt::U(lv)), Some(FullInt::U(rv))) => lv < rv, + _ => return, + } { + span_ineffective_operation(cx, span, arg); + } +} + fn check(cx: &LateContext<'_>, e: &Expr<'_>, m: i8, span: Span, arg: Span) { if let Some(Constant::Int(v)) = constant_simple(cx, cx.typeck_results(), e).map(Constant::peel_refs) { let check = match *cx.typeck_results().expr_ty(e).peel_refs().kind() { @@ -83,15 +96,19 @@ fn check(cx: &LateContext<'_>, e: &Expr<'_>, m: i8, span: Span, arg: Span) { 1 => v == 1, _ => unreachable!(), } { - span_lint( - cx, - IDENTITY_OP, - span, - &format!( - "the operation is ineffective. Consider reducing it to `{}`", - snippet(cx, arg, "..") - ), - ); + span_ineffective_operation(cx, span, arg); } } } + +fn span_ineffective_operation(cx: &LateContext<'_>, span: Span, arg: Span) { + span_lint( + cx, + IDENTITY_OP, + span, + &format!( + "the operation is ineffective. Consider reducing it to `{}`", + snippet(cx, arg, "..") + ), + ); +} diff --git a/tests/ui/identity_op.rs b/tests/ui/identity_op.rs index 12bbda71f43..5e120947646 100644 --- a/tests/ui/identity_op.rs +++ b/tests/ui/identity_op.rs @@ -66,4 +66,10 @@ fn main() { let b = a << 0; // no error: non-integer 1 * Meter; // no error: non-integer + + 2 % 3; + -2 % 3; + x + 1 % 3; + (x + 1) % 3; // no error + 4 % 3; // no error } diff --git a/tests/ui/identity_op.stderr b/tests/ui/identity_op.stderr index 0103cf5457e..cb9757d1158 100644 --- a/tests/ui/identity_op.stderr +++ b/tests/ui/identity_op.stderr @@ -78,5 +78,23 @@ error: the operation is ineffective. Consider reducing it to `x` LL | x >> &0; | ^^^^^^^ -error: aborting due to 13 previous errors +error: the operation is ineffective. Consider reducing it to `2` + --> $DIR/identity_op.rs:70:5 + | +LL | 2 % 3; + | ^^^^^ + +error: the operation is ineffective. Consider reducing it to `-2` + --> $DIR/identity_op.rs:71:5 + | +LL | -2 % 3; + | ^^^^^^ + +error: the operation is ineffective. Consider reducing it to `1` + --> $DIR/identity_op.rs:72:9 + | +LL | x + 1 % 3; + | ^^^^^ + +error: aborting due to 16 previous errors diff --git a/tests/ui/modulo_arithmetic_integral_const.rs b/tests/ui/modulo_arithmetic_integral_const.rs index 047a29fa1e3..3ebe46bc5be 100644 --- a/tests/ui/modulo_arithmetic_integral_const.rs +++ b/tests/ui/modulo_arithmetic_integral_const.rs @@ -1,5 +1,10 @@ #![warn(clippy::modulo_arithmetic)] -#![allow(clippy::no_effect, clippy::unnecessary_operation, clippy::modulo_one)] +#![allow( + clippy::no_effect, + clippy::unnecessary_operation, + clippy::modulo_one, + clippy::identity_op +)] fn main() { // Lint when both sides are const and of the opposite sign diff --git a/tests/ui/modulo_arithmetic_integral_const.stderr b/tests/ui/modulo_arithmetic_integral_const.stderr index 64335f35f0f..11b5f77461b 100644 --- a/tests/ui/modulo_arithmetic_integral_const.stderr +++ b/tests/ui/modulo_arithmetic_integral_const.stderr @@ -1,5 +1,5 @@ error: you are using modulo operator on constants with different signs: `-1 % 2` - --> $DIR/modulo_arithmetic_integral_const.rs:6:5 + --> $DIR/modulo_arithmetic_integral_const.rs:11:5 | LL | -1 % 2; | ^^^^^^ @@ -9,7 +9,7 @@ LL | -1 % 2; = note: or consider using `rem_euclid` or similar function error: you are using modulo operator on constants with different signs: `1 % -2` - --> $DIR/modulo_arithmetic_integral_const.rs:7:5 + --> $DIR/modulo_arithmetic_integral_const.rs:12:5 | LL | 1 % -2; | ^^^^^^ @@ -18,7 +18,7 @@ LL | 1 % -2; = note: or consider using `rem_euclid` or similar function error: you are using modulo operator on constants with different signs: `-1 % 3` - --> $DIR/modulo_arithmetic_integral_const.rs:8:5 + --> $DIR/modulo_arithmetic_integral_const.rs:13:5 | LL | (1 - 2) % (1 + 2); | ^^^^^^^^^^^^^^^^^ @@ -27,7 +27,7 @@ LL | (1 - 2) % (1 + 2); = note: or consider using `rem_euclid` or similar function error: you are using modulo operator on constants with different signs: `3 % -1` - --> $DIR/modulo_arithmetic_integral_const.rs:9:5 + --> $DIR/modulo_arithmetic_integral_const.rs:14:5 | LL | (1 + 2) % (1 - 2); | ^^^^^^^^^^^^^^^^^ @@ -36,7 +36,7 @@ LL | (1 + 2) % (1 - 2); = note: or consider using `rem_euclid` or similar function error: you are using modulo operator on constants with different signs: `-35 % 300000` - --> $DIR/modulo_arithmetic_integral_const.rs:10:5 + --> $DIR/modulo_arithmetic_integral_const.rs:15:5 | LL | 35 * (7 - 4 * 2) % (-500 * -600); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -45,7 +45,7 @@ LL | 35 * (7 - 4 * 2) % (-500 * -600); = note: or consider using `rem_euclid` or similar function error: you are using modulo operator on constants with different signs: `-1 % 2` - --> $DIR/modulo_arithmetic_integral_const.rs:12:5 + --> $DIR/modulo_arithmetic_integral_const.rs:17:5 | LL | -1i8 % 2i8; | ^^^^^^^^^^ @@ -54,7 +54,7 @@ LL | -1i8 % 2i8; = note: or consider using `rem_euclid` or similar function error: you are using modulo operator on constants with different signs: `1 % -2` - --> $DIR/modulo_arithmetic_integral_const.rs:13:5 + --> $DIR/modulo_arithmetic_integral_const.rs:18:5 | LL | 1i8 % -2i8; | ^^^^^^^^^^ @@ -63,7 +63,7 @@ LL | 1i8 % -2i8; = note: or consider using `rem_euclid` or similar function error: you are using modulo operator on constants with different signs: `-1 % 2` - --> $DIR/modulo_arithmetic_integral_const.rs:14:5 + --> $DIR/modulo_arithmetic_integral_const.rs:19:5 | LL | -1i16 % 2i16; | ^^^^^^^^^^^^ @@ -72,7 +72,7 @@ LL | -1i16 % 2i16; = note: or consider using `rem_euclid` or similar function error: you are using modulo operator on constants with different signs: `1 % -2` - --> $DIR/modulo_arithmetic_integral_const.rs:15:5 + --> $DIR/modulo_arithmetic_integral_const.rs:20:5 | LL | 1i16 % -2i16; | ^^^^^^^^^^^^ @@ -81,7 +81,7 @@ LL | 1i16 % -2i16; = note: or consider using `rem_euclid` or similar function error: you are using modulo operator on constants with different signs: `-1 % 2` - --> $DIR/modulo_arithmetic_integral_const.rs:16:5 + --> $DIR/modulo_arithmetic_integral_const.rs:21:5 | LL | -1i32 % 2i32; | ^^^^^^^^^^^^ @@ -90,7 +90,7 @@ LL | -1i32 % 2i32; = note: or consider using `rem_euclid` or similar function error: you are using modulo operator on constants with different signs: `1 % -2` - --> $DIR/modulo_arithmetic_integral_const.rs:17:5 + --> $DIR/modulo_arithmetic_integral_const.rs:22:5 | LL | 1i32 % -2i32; | ^^^^^^^^^^^^ @@ -99,7 +99,7 @@ LL | 1i32 % -2i32; = note: or consider using `rem_euclid` or similar function error: you are using modulo operator on constants with different signs: `-1 % 2` - --> $DIR/modulo_arithmetic_integral_const.rs:18:5 + --> $DIR/modulo_arithmetic_integral_const.rs:23:5 | LL | -1i64 % 2i64; | ^^^^^^^^^^^^ @@ -108,7 +108,7 @@ LL | -1i64 % 2i64; = note: or consider using `rem_euclid` or similar function error: you are using modulo operator on constants with different signs: `1 % -2` - --> $DIR/modulo_arithmetic_integral_const.rs:19:5 + --> $DIR/modulo_arithmetic_integral_const.rs:24:5 | LL | 1i64 % -2i64; | ^^^^^^^^^^^^ @@ -117,7 +117,7 @@ LL | 1i64 % -2i64; = note: or consider using `rem_euclid` or similar function error: you are using modulo operator on constants with different signs: `-1 % 2` - --> $DIR/modulo_arithmetic_integral_const.rs:20:5 + --> $DIR/modulo_arithmetic_integral_const.rs:25:5 | LL | -1i128 % 2i128; | ^^^^^^^^^^^^^^ @@ -126,7 +126,7 @@ LL | -1i128 % 2i128; = note: or consider using `rem_euclid` or similar function error: you are using modulo operator on constants with different signs: `1 % -2` - --> $DIR/modulo_arithmetic_integral_const.rs:21:5 + --> $DIR/modulo_arithmetic_integral_const.rs:26:5 | LL | 1i128 % -2i128; | ^^^^^^^^^^^^^^ @@ -135,7 +135,7 @@ LL | 1i128 % -2i128; = note: or consider using `rem_euclid` or similar function error: you are using modulo operator on constants with different signs: `-1 % 2` - --> $DIR/modulo_arithmetic_integral_const.rs:22:5 + --> $DIR/modulo_arithmetic_integral_const.rs:27:5 | LL | -1isize % 2isize; | ^^^^^^^^^^^^^^^^ @@ -144,7 +144,7 @@ LL | -1isize % 2isize; = note: or consider using `rem_euclid` or similar function error: you are using modulo operator on constants with different signs: `1 % -2` - --> $DIR/modulo_arithmetic_integral_const.rs:23:5 + --> $DIR/modulo_arithmetic_integral_const.rs:28:5 | LL | 1isize % -2isize; | ^^^^^^^^^^^^^^^^ |