From 2f9f204123b857606e7b65d217a3b71920fccf20 Mon Sep 17 00:00:00 2001 From: vohoanglong0107 Date: Wed, 28 Feb 2024 04:31:41 +0000 Subject: [PATCH] feat: unnecessary_min_max lint --- CHANGELOG.md | 1 + clippy_lints/src/declared_lints.rs | 1 + clippy_lints/src/methods/mod.rs | 30 +++ .../src/methods/unnecessary_min_or_max.rs | 90 +++++++++ clippy_utils/src/consts.rs | 17 +- tests/ui/auxiliary/external_consts.rs | 1 + tests/ui/cast.rs | 1 + tests/ui/cast.stderr | 184 +++++++++--------- tests/ui/unnecessary_min_or_max.fixed | 67 +++++++ tests/ui/unnecessary_min_or_max.rs | 67 +++++++ tests/ui/unnecessary_min_or_max.stderr | 107 ++++++++++ 11 files changed, 472 insertions(+), 94 deletions(-) create mode 100644 clippy_lints/src/methods/unnecessary_min_or_max.rs create mode 100644 tests/ui/auxiliary/external_consts.rs create mode 100644 tests/ui/unnecessary_min_or_max.fixed create mode 100644 tests/ui/unnecessary_min_or_max.rs create mode 100644 tests/ui/unnecessary_min_or_max.stderr diff --git a/CHANGELOG.md b/CHANGELOG.md index 3973edddb..fe9fbd486 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -5917,6 +5917,7 @@ Released 2018-09-13 [`unnecessary_lazy_evaluations`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_lazy_evaluations [`unnecessary_literal_unwrap`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_literal_unwrap [`unnecessary_map_on_constructor`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_map_on_constructor +[`unnecessary_min_or_max`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_min_or_max [`unnecessary_mut_passed`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_mut_passed [`unnecessary_operation`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_operation [`unnecessary_owned_empty_strings`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_owned_empty_strings diff --git a/clippy_lints/src/declared_lints.rs b/clippy_lints/src/declared_lints.rs index 8abe5d47b..3b3d0db79 100644 --- a/clippy_lints/src/declared_lints.rs +++ b/clippy_lints/src/declared_lints.rs @@ -471,6 +471,7 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[ crate::methods::UNNECESSARY_JOIN_INFO, crate::methods::UNNECESSARY_LAZY_EVALUATIONS_INFO, crate::methods::UNNECESSARY_LITERAL_UNWRAP_INFO, + crate::methods::UNNECESSARY_MIN_OR_MAX_INFO, crate::methods::UNNECESSARY_RESULT_MAP_OR_ELSE_INFO, crate::methods::UNNECESSARY_SORT_BY_INFO, crate::methods::UNNECESSARY_TO_OWNED_INFO, diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index 01438b8e8..1408f4548 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -117,6 +117,7 @@ mod unnecessary_iter_cloned; mod unnecessary_join; mod unnecessary_lazy_eval; mod unnecessary_literal_unwrap; +mod unnecessary_min_or_max; mod unnecessary_result_map_or_else; mod unnecessary_sort_by; mod unnecessary_to_owned; @@ -3945,6 +3946,31 @@ declare_clippy_lint! { "cloning an `Option` via `as_ref().cloned()`" } +declare_clippy_lint! { + /// ### What it does + /// Checks for unnecessary calls to `min()` or `max()` in the following cases + /// - Either both side is constant + /// - One side is clearly larger than the other, like i32::MIN and an i32 variable + /// + /// ### Why is this bad? + /// + /// In the aformentioned cases it is not necessary to call `min()` or `max()` + /// to compare values, it may even cause confusion. + /// + /// ### Example + /// ```no_run + /// let _ = 0.min(7_u32); + /// ``` + /// Use instead: + /// ```no_run + /// let _ = 0; + /// ``` + #[clippy::version = "1.78.0"] + pub UNNECESSARY_MIN_OR_MAX, + complexity, + "using 'min()/max()' when there is no need for it" +} + declare_clippy_lint! { /// ### What it does /// Checks for usage of `.map_or_else()` "map closure" for `Result` type. @@ -4267,6 +4293,7 @@ impl_lint_pass!(Methods => [ UNNECESSARY_GET_THEN_CHECK, NEEDLESS_CHARACTER_ITERATION, MANUAL_INSPECT, + UNNECESSARY_MIN_OR_MAX, ]); /// Extracts a method call name, args, and `Span` of the method name. @@ -4566,6 +4593,9 @@ impl Methods { Some(("bytes", recv2, [], _, _)) => bytes_count_to_len::check(cx, expr, recv, recv2), _ => {}, }, + ("min" | "max", [arg]) => { + unnecessary_min_or_max::check(cx, expr, name, recv, arg); + }, ("drain", ..) => { if let Node::Stmt(Stmt { hir_id: _, kind, .. }) = cx.tcx.parent_hir_node(expr.hir_id) && matches!(kind, StmtKind::Semi(_)) diff --git a/clippy_lints/src/methods/unnecessary_min_or_max.rs b/clippy_lints/src/methods/unnecessary_min_or_max.rs new file mode 100644 index 000000000..78851d412 --- /dev/null +++ b/clippy_lints/src/methods/unnecessary_min_or_max.rs @@ -0,0 +1,90 @@ +use std::cmp::Ordering; + +use super::UNNECESSARY_MIN_OR_MAX; +use clippy_utils::diagnostics::span_lint_and_sugg; + +use clippy_utils::consts::{constant, constant_with_source, Constant, ConstantSource, FullInt}; +use clippy_utils::source::snippet; + +use rustc_errors::Applicability; +use rustc_hir::Expr; +use rustc_lint::LateContext; +use rustc_middle::ty; +use rustc_span::Span; + +pub(super) fn check<'tcx>( + cx: &LateContext<'tcx>, + expr: &'tcx Expr<'_>, + name: &str, + recv: &'tcx Expr<'_>, + arg: &'tcx Expr<'_>, +) { + let typeck_results = cx.typeck_results(); + if let Some((left, ConstantSource::Local | ConstantSource::CoreConstant)) = + constant_with_source(cx, typeck_results, recv) + && let Some((right, ConstantSource::Local | ConstantSource::CoreConstant)) = + constant_with_source(cx, typeck_results, arg) + { + let Some(ord) = Constant::partial_cmp(cx.tcx, typeck_results.expr_ty(recv), &left, &right) else { + return; + }; + + lint(cx, expr, name, recv.span, arg.span, ord); + } else if let Some(extrema) = detect_extrema(cx, recv) { + let ord = match extrema { + Extrema::Minimum => Ordering::Less, + Extrema::Maximum => Ordering::Greater, + }; + lint(cx, expr, name, recv.span, arg.span, ord); + } else if let Some(extrema) = detect_extrema(cx, arg) { + let ord = match extrema { + Extrema::Minimum => Ordering::Greater, + Extrema::Maximum => Ordering::Less, + }; + lint(cx, expr, name, recv.span, arg.span, ord); + } +} + +fn lint(cx: &LateContext<'_>, expr: &Expr<'_>, name: &str, lhs: Span, rhs: Span, order: Ordering) { + let cmp_str = if order.is_ge() { "smaller" } else { "greater" }; + + let suggested_value = if (name == "min" && order.is_ge()) || (name == "max" && order.is_le()) { + snippet(cx, rhs, "..") + } else { + snippet(cx, lhs, "..") + }; + + span_lint_and_sugg( + cx, + UNNECESSARY_MIN_OR_MAX, + expr.span, + format!( + "`{}` is never {} than `{}` and has therefore no effect", + snippet(cx, lhs, ".."), + cmp_str, + snippet(cx, rhs, "..") + ), + "try", + suggested_value.to_string(), + Applicability::MachineApplicable, + ); +} + +#[derive(Debug)] +enum Extrema { + Minimum, + Maximum, +} +fn detect_extrema<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option { + let ty = cx.typeck_results().expr_ty(expr); + + let cv = constant(cx, cx.typeck_results(), expr)?; + + match (cv.int_value(cx, ty)?, ty.kind()) { + (FullInt::S(i), &ty::Int(ity)) if i == i128::MIN >> (128 - ity.bit_width()?) => Some(Extrema::Minimum), + (FullInt::S(i), &ty::Int(ity)) if i == i128::MAX >> (128 - ity.bit_width()?) => Some(Extrema::Maximum), + (FullInt::U(i), &ty::Uint(uty)) if i == u128::MAX >> (128 - uty.bit_width()?) => Some(Extrema::Maximum), + (FullInt::U(0), &ty::Uint(_)) => Some(Extrema::Minimum), + _ => None, + } +} diff --git a/clippy_utils/src/consts.rs b/clippy_utils/src/consts.rs index cfd142fe1..8f6389ee0 100644 --- a/clippy_utils/src/consts.rs +++ b/clippy_utils/src/consts.rs @@ -1,5 +1,6 @@ #![allow(clippy::float_cmp)] +use crate::macros::HirNode; use crate::source::{get_source_text, walk_span_to_context}; use crate::{clip, is_direct_expn_of, sext, unsext}; @@ -15,7 +16,7 @@ use rustc_middle::ty::{self, EarlyBinder, FloatTy, GenericArgsRef, IntTy, List, use rustc_middle::{bug, mir, span_bug}; use rustc_span::def_id::DefId; use rustc_span::symbol::{Ident, Symbol}; -use rustc_span::SyntaxContext; +use rustc_span::{sym, SyntaxContext}; use rustc_target::abi::Size; use std::cmp::Ordering; use std::hash::{Hash, Hasher}; @@ -302,6 +303,8 @@ pub enum ConstantSource { Local, /// The value is dependent on a defined constant. Constant, + /// The value is dependent on a constant defined in `core` crate. + CoreConstant, } impl ConstantSource { pub fn is_local(&self) -> bool { @@ -415,9 +418,19 @@ impl<'a, 'tcx> ConstEvalLateContext<'a, 'tcx> { ExprKind::ConstBlock(ConstBlock { body, .. }) => self.expr(self.lcx.tcx.hir().body(body).value), ExprKind::DropTemps(e) => self.expr(e), ExprKind::Path(ref qpath) => { + let is_core_crate = if let Some(def_id) = self.lcx.qpath_res(qpath, e.hir_id()).opt_def_id() { + self.lcx.tcx.crate_name(def_id.krate) == sym::core + } else { + false + }; self.fetch_path_and_apply(qpath, e.hir_id, self.typeck_results.expr_ty(e), |this, result| { let result = mir_to_const(this.lcx, result)?; - this.source = ConstantSource::Constant; + // If source is already Constant we wouldn't want to override it with CoreConstant + this.source = if is_core_crate && !matches!(this.source, ConstantSource::Constant) { + ConstantSource::CoreConstant + } else { + ConstantSource::Constant + }; Some(result) }) }, diff --git a/tests/ui/auxiliary/external_consts.rs b/tests/ui/auxiliary/external_consts.rs new file mode 100644 index 000000000..1885ba341 --- /dev/null +++ b/tests/ui/auxiliary/external_consts.rs @@ -0,0 +1 @@ +pub const MAGIC_NUMBER: i32 = 1; diff --git a/tests/ui/cast.rs b/tests/ui/cast.rs index 453d62ce6..351325e9b 100644 --- a/tests/ui/cast.rs +++ b/tests/ui/cast.rs @@ -12,6 +12,7 @@ #![allow( clippy::cast_abs_to_unsigned, clippy::no_effect, + clippy::unnecessary_min_or_max, clippy::unnecessary_operation, clippy::unnecessary_literal_unwrap, clippy::identity_op diff --git a/tests/ui/cast.stderr b/tests/ui/cast.stderr index 43c0d8f4e..f14c3c8d8 100644 --- a/tests/ui/cast.stderr +++ b/tests/ui/cast.stderr @@ -1,5 +1,5 @@ error: casting `i32` to `f32` causes a loss of precision (`i32` is 32 bits wide, but `f32`'s mantissa is only 23 bits wide) - --> tests/ui/cast.rs:23:5 + --> tests/ui/cast.rs:24:5 | LL | x0 as f32; | ^^^^^^^^^ @@ -8,37 +8,37 @@ LL | x0 as f32; = help: to override `-D warnings` add `#[allow(clippy::cast_precision_loss)]` error: casting `i64` to `f32` causes a loss of precision (`i64` is 64 bits wide, but `f32`'s mantissa is only 23 bits wide) - --> tests/ui/cast.rs:27:5 + --> tests/ui/cast.rs:28:5 | LL | x1 as f32; | ^^^^^^^^^ error: casting `i64` to `f64` causes a loss of precision (`i64` is 64 bits wide, but `f64`'s mantissa is only 52 bits wide) - --> tests/ui/cast.rs:29:5 + --> tests/ui/cast.rs:30:5 | LL | x1 as f64; | ^^^^^^^^^ error: casting `u32` to `f32` causes a loss of precision (`u32` is 32 bits wide, but `f32`'s mantissa is only 23 bits wide) - --> tests/ui/cast.rs:32:5 + --> tests/ui/cast.rs:33:5 | LL | x2 as f32; | ^^^^^^^^^ error: casting `u64` to `f32` causes a loss of precision (`u64` is 64 bits wide, but `f32`'s mantissa is only 23 bits wide) - --> tests/ui/cast.rs:35:5 + --> tests/ui/cast.rs:36:5 | LL | x3 as f32; | ^^^^^^^^^ error: casting `u64` to `f64` causes a loss of precision (`u64` is 64 bits wide, but `f64`'s mantissa is only 52 bits wide) - --> tests/ui/cast.rs:37:5 + --> tests/ui/cast.rs:38:5 | LL | x3 as f64; | ^^^^^^^^^ error: casting `f32` to `i32` may truncate the value - --> tests/ui/cast.rs:40:5 + --> tests/ui/cast.rs:41:5 | LL | 1f32 as i32; | ^^^^^^^^^^^ @@ -48,7 +48,7 @@ LL | 1f32 as i32; = help: to override `-D warnings` add `#[allow(clippy::cast_possible_truncation)]` error: casting `f32` to `u32` may truncate the value - --> tests/ui/cast.rs:42:5 + --> tests/ui/cast.rs:43:5 | LL | 1f32 as u32; | ^^^^^^^^^^^ @@ -56,7 +56,7 @@ LL | 1f32 as u32; = help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ... error: casting `f32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:42:5 + --> tests/ui/cast.rs:43:5 | LL | 1f32 as u32; | ^^^^^^^^^^^ @@ -65,7 +65,7 @@ LL | 1f32 as u32; = help: to override `-D warnings` add `#[allow(clippy::cast_sign_loss)]` error: casting `f64` to `f32` may truncate the value - --> tests/ui/cast.rs:46:5 + --> tests/ui/cast.rs:47:5 | LL | 1f64 as f32; | ^^^^^^^^^^^ @@ -73,7 +73,7 @@ LL | 1f64 as f32; = help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ... error: casting `i32` to `i8` may truncate the value - --> tests/ui/cast.rs:48:5 + --> tests/ui/cast.rs:49:5 | LL | 1i32 as i8; | ^^^^^^^^^^ @@ -85,7 +85,7 @@ LL | i8::try_from(1i32); | ~~~~~~~~~~~~~~~~~~ error: casting `i32` to `u8` may truncate the value - --> tests/ui/cast.rs:50:5 + --> tests/ui/cast.rs:51:5 | LL | 1i32 as u8; | ^^^^^^^^^^ @@ -97,7 +97,7 @@ LL | u8::try_from(1i32); | ~~~~~~~~~~~~~~~~~~ error: casting `f64` to `isize` may truncate the value - --> tests/ui/cast.rs:52:5 + --> tests/ui/cast.rs:53:5 | LL | 1f64 as isize; | ^^^^^^^^^^^^^ @@ -105,7 +105,7 @@ LL | 1f64 as isize; = help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ... error: casting `f64` to `usize` may truncate the value - --> tests/ui/cast.rs:54:5 + --> tests/ui/cast.rs:55:5 | LL | 1f64 as usize; | ^^^^^^^^^^^^^ @@ -113,13 +113,13 @@ LL | 1f64 as usize; = help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ... error: casting `f64` to `usize` may lose the sign of the value - --> tests/ui/cast.rs:54:5 + --> tests/ui/cast.rs:55:5 | LL | 1f64 as usize; | ^^^^^^^^^^^^^ error: casting `u32` to `u16` may truncate the value - --> tests/ui/cast.rs:57:5 + --> tests/ui/cast.rs:58:5 | LL | 1f32 as u32 as u16; | ^^^^^^^^^^^^^^^^^^ @@ -131,7 +131,7 @@ LL | u16::try_from(1f32 as u32); | ~~~~~~~~~~~~~~~~~~~~~~~~~~ error: casting `f32` to `u32` may truncate the value - --> tests/ui/cast.rs:57:5 + --> tests/ui/cast.rs:58:5 | LL | 1f32 as u32 as u16; | ^^^^^^^^^^^ @@ -139,13 +139,13 @@ LL | 1f32 as u32 as u16; = help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ... error: casting `f32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:57:5 + --> tests/ui/cast.rs:58:5 | LL | 1f32 as u32 as u16; | ^^^^^^^^^^^ error: casting `i32` to `i8` may truncate the value - --> tests/ui/cast.rs:62:22 + --> tests/ui/cast.rs:63:22 | LL | let _x: i8 = 1i32 as _; | ^^^^^^^^^ @@ -157,7 +157,7 @@ LL | let _x: i8 = 1i32.try_into(); | ~~~~~~~~~~~~~~~ error: casting `f32` to `i32` may truncate the value - --> tests/ui/cast.rs:64:9 + --> tests/ui/cast.rs:65:9 | LL | 1f32 as i32; | ^^^^^^^^^^^ @@ -165,7 +165,7 @@ LL | 1f32 as i32; = help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ... error: casting `f64` to `i32` may truncate the value - --> tests/ui/cast.rs:66:9 + --> tests/ui/cast.rs:67:9 | LL | 1f64 as i32; | ^^^^^^^^^^^ @@ -173,7 +173,7 @@ LL | 1f64 as i32; = help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ... error: casting `f32` to `u8` may truncate the value - --> tests/ui/cast.rs:68:9 + --> tests/ui/cast.rs:69:9 | LL | 1f32 as u8; | ^^^^^^^^^^ @@ -181,13 +181,13 @@ LL | 1f32 as u8; = help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ... error: casting `f32` to `u8` may lose the sign of the value - --> tests/ui/cast.rs:68:9 + --> tests/ui/cast.rs:69:9 | LL | 1f32 as u8; | ^^^^^^^^^^ error: casting `u8` to `i8` may wrap around the value - --> tests/ui/cast.rs:73:5 + --> tests/ui/cast.rs:74:5 | LL | 1u8 as i8; | ^^^^^^^^^ @@ -196,31 +196,31 @@ LL | 1u8 as i8; = help: to override `-D warnings` add `#[allow(clippy::cast_possible_wrap)]` error: casting `u16` to `i16` may wrap around the value - --> tests/ui/cast.rs:76:5 + --> tests/ui/cast.rs:77:5 | LL | 1u16 as i16; | ^^^^^^^^^^^ error: casting `u32` to `i32` may wrap around the value - --> tests/ui/cast.rs:78:5 + --> tests/ui/cast.rs:79:5 | LL | 1u32 as i32; | ^^^^^^^^^^^ error: casting `u64` to `i64` may wrap around the value - --> tests/ui/cast.rs:80:5 + --> tests/ui/cast.rs:81:5 | LL | 1u64 as i64; | ^^^^^^^^^^^ error: casting `usize` to `isize` may wrap around the value - --> tests/ui/cast.rs:82:5 + --> tests/ui/cast.rs:83:5 | LL | 1usize as isize; | ^^^^^^^^^^^^^^^ error: casting `usize` to `i8` may truncate the value - --> tests/ui/cast.rs:85:5 + --> tests/ui/cast.rs:86:5 | LL | 1usize as i8; | ^^^^^^^^^^^^ @@ -232,7 +232,7 @@ LL | i8::try_from(1usize); | ~~~~~~~~~~~~~~~~~~~~ error: casting `usize` to `i16` may truncate the value - --> tests/ui/cast.rs:88:5 + --> tests/ui/cast.rs:89:5 | LL | 1usize as i16; | ^^^^^^^^^^^^^ @@ -244,7 +244,7 @@ LL | i16::try_from(1usize); | ~~~~~~~~~~~~~~~~~~~~~ error: casting `usize` to `i16` may wrap around the value on targets with 16-bit wide pointers - --> tests/ui/cast.rs:88:5 + --> tests/ui/cast.rs:89:5 | LL | 1usize as i16; | ^^^^^^^^^^^^^ @@ -253,7 +253,7 @@ LL | 1usize as i16; = note: for more information see https://doc.rust-lang.org/reference/types/numeric.html#machine-dependent-integer-types error: casting `usize` to `i32` may truncate the value on targets with 64-bit wide pointers - --> tests/ui/cast.rs:93:5 + --> tests/ui/cast.rs:94:5 | LL | 1usize as i32; | ^^^^^^^^^^^^^ @@ -265,19 +265,19 @@ LL | i32::try_from(1usize); | ~~~~~~~~~~~~~~~~~~~~~ error: casting `usize` to `i32` may wrap around the value on targets with 32-bit wide pointers - --> tests/ui/cast.rs:93:5 + --> tests/ui/cast.rs:94:5 | LL | 1usize as i32; | ^^^^^^^^^^^^^ error: casting `usize` to `i64` may wrap around the value on targets with 64-bit wide pointers - --> tests/ui/cast.rs:97:5 + --> tests/ui/cast.rs:98:5 | LL | 1usize as i64; | ^^^^^^^^^^^^^ error: casting `u16` to `isize` may wrap around the value on targets with 16-bit wide pointers - --> tests/ui/cast.rs:102:5 + --> tests/ui/cast.rs:103:5 | LL | 1u16 as isize; | ^^^^^^^^^^^^^ @@ -286,13 +286,13 @@ LL | 1u16 as isize; = note: for more information see https://doc.rust-lang.org/reference/types/numeric.html#machine-dependent-integer-types error: casting `u32` to `isize` may wrap around the value on targets with 32-bit wide pointers - --> tests/ui/cast.rs:106:5 + --> tests/ui/cast.rs:107:5 | LL | 1u32 as isize; | ^^^^^^^^^^^^^ error: casting `u64` to `isize` may truncate the value on targets with 32-bit wide pointers - --> tests/ui/cast.rs:109:5 + --> tests/ui/cast.rs:110:5 | LL | 1u64 as isize; | ^^^^^^^^^^^^^ @@ -304,55 +304,55 @@ LL | isize::try_from(1u64); | ~~~~~~~~~~~~~~~~~~~~~ error: casting `u64` to `isize` may wrap around the value on targets with 64-bit wide pointers - --> tests/ui/cast.rs:109:5 + --> tests/ui/cast.rs:110:5 | LL | 1u64 as isize; | ^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:114:5 + --> tests/ui/cast.rs:115:5 | LL | -1i32 as u32; | ^^^^^^^^^^^^ error: casting `isize` to `usize` may lose the sign of the value - --> tests/ui/cast.rs:117:5 + --> tests/ui/cast.rs:118:5 | LL | -1isize as usize; | ^^^^^^^^^^^^^^^^ error: casting `i8` to `u8` may lose the sign of the value - --> tests/ui/cast.rs:128:5 + --> tests/ui/cast.rs:129:5 | LL | (i8::MIN).abs() as u8; | ^^^^^^^^^^^^^^^^^^^^^ error: casting `i64` to `u64` may lose the sign of the value - --> tests/ui/cast.rs:132:5 + --> tests/ui/cast.rs:133:5 | LL | (-1i64).abs() as u64; | ^^^^^^^^^^^^^^^^^^^^ error: casting `isize` to `usize` may lose the sign of the value - --> tests/ui/cast.rs:133:5 + --> tests/ui/cast.rs:134:5 | LL | (-1isize).abs() as usize; | ^^^^^^^^^^^^^^^^^^^^^^^^ error: casting `i64` to `u64` may lose the sign of the value - --> tests/ui/cast.rs:140:5 + --> tests/ui/cast.rs:141:5 | LL | (unsafe { (-1i64).checked_abs().unwrap_unchecked() }) as u64; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: casting `i64` to `u64` may lose the sign of the value - --> tests/ui/cast.rs:155:5 + --> tests/ui/cast.rs:156:5 | LL | (unsafe { (-1i64).checked_isqrt().unwrap_unchecked() }) as u64; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: casting `i64` to `i8` may truncate the value - --> tests/ui/cast.rs:206:5 + --> tests/ui/cast.rs:207:5 | LL | (-99999999999i64).min(1) as i8; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -364,7 +364,7 @@ LL | i8::try_from((-99999999999i64).min(1)); | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: casting `u64` to `u8` may truncate the value - --> tests/ui/cast.rs:220:5 + --> tests/ui/cast.rs:221:5 | LL | 999999u64.clamp(0, 256) as u8; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -376,7 +376,7 @@ LL | u8::try_from(999999u64.clamp(0, 256)); | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: casting `main::E2` to `u8` may truncate the value - --> tests/ui/cast.rs:243:21 + --> tests/ui/cast.rs:244:21 | LL | let _ = self as u8; | ^^^^^^^^^^ @@ -388,7 +388,7 @@ LL | let _ = u8::try_from(self); | ~~~~~~~~~~~~~~~~~~ error: casting `main::E2::B` to `u8` will truncate the value - --> tests/ui/cast.rs:245:21 + --> tests/ui/cast.rs:246:21 | LL | let _ = Self::B as u8; | ^^^^^^^^^^^^^ @@ -397,7 +397,7 @@ LL | let _ = Self::B as u8; = help: to override `-D warnings` add `#[allow(clippy::cast_enum_truncation)]` error: casting `main::E5` to `i8` may truncate the value - --> tests/ui/cast.rs:287:21 + --> tests/ui/cast.rs:288:21 | LL | let _ = self as i8; | ^^^^^^^^^^ @@ -409,13 +409,13 @@ LL | let _ = i8::try_from(self); | ~~~~~~~~~~~~~~~~~~ error: casting `main::E5::A` to `i8` will truncate the value - --> tests/ui/cast.rs:289:21 + --> tests/ui/cast.rs:290:21 | LL | let _ = Self::A as i8; | ^^^^^^^^^^^^^ error: casting `main::E6` to `i16` may truncate the value - --> tests/ui/cast.rs:306:21 + --> tests/ui/cast.rs:307:21 | LL | let _ = self as i16; | ^^^^^^^^^^^ @@ -427,7 +427,7 @@ LL | let _ = i16::try_from(self); | ~~~~~~~~~~~~~~~~~~~ error: casting `main::E7` to `usize` may truncate the value on targets with 32-bit wide pointers - --> tests/ui/cast.rs:325:21 + --> tests/ui/cast.rs:326:21 | LL | let _ = self as usize; | ^^^^^^^^^^^^^ @@ -439,7 +439,7 @@ LL | let _ = usize::try_from(self); | ~~~~~~~~~~~~~~~~~~~~~ error: casting `main::E10` to `u16` may truncate the value - --> tests/ui/cast.rs:372:21 + --> tests/ui/cast.rs:373:21 | LL | let _ = self as u16; | ^^^^^^^^^^^ @@ -451,7 +451,7 @@ LL | let _ = u16::try_from(self); | ~~~~~~~~~~~~~~~~~~~ error: casting `u32` to `u8` may truncate the value - --> tests/ui/cast.rs:383:13 + --> tests/ui/cast.rs:384:13 | LL | let c = (q >> 16) as u8; | ^^^^^^^^^^^^^^^ @@ -463,7 +463,7 @@ LL | let c = u8::try_from(q >> 16); | ~~~~~~~~~~~~~~~~~~~~~ error: casting `u32` to `u8` may truncate the value - --> tests/ui/cast.rs:387:13 + --> tests/ui/cast.rs:388:13 | LL | let c = (q / 1000) as u8; | ^^^^^^^^^^^^^^^^ @@ -475,85 +475,85 @@ LL | let c = u8::try_from(q / 1000); | ~~~~~~~~~~~~~~~~~~~~~~ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:399:9 + --> tests/ui/cast.rs:400:9 | LL | (x * x) as u32; | ^^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:404:32 + --> tests/ui/cast.rs:405:32 | LL | let _a = |x: i32| -> u32 { (x * x * x * x) as u32 }; | ^^^^^^^^^^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:406:5 + --> tests/ui/cast.rs:407:5 | LL | (2_i32).checked_pow(3).unwrap() as u32; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:407:5 + --> tests/ui/cast.rs:408:5 | LL | (-2_i32).pow(3) as u32; | ^^^^^^^^^^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:412:5 + --> tests/ui/cast.rs:413:5 | LL | (-5_i32 % 2) as u32; | ^^^^^^^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:414:5 + --> tests/ui/cast.rs:415:5 | LL | (-5_i32 % -2) as u32; | ^^^^^^^^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:417:5 + --> tests/ui/cast.rs:418:5 | LL | (-2_i32 >> 1) as u32; | ^^^^^^^^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:421:5 + --> tests/ui/cast.rs:422:5 | LL | (x * x) as u32; | ^^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:422:5 + --> tests/ui/cast.rs:423:5 | LL | (x * x * x) as u32; | ^^^^^^^^^^^^^^^^^^ error: casting `i16` to `u16` may lose the sign of the value - --> tests/ui/cast.rs:426:5 + --> tests/ui/cast.rs:427:5 | LL | (y * y * y * y * -2) as u16; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: casting `i16` to `u16` may lose the sign of the value - --> tests/ui/cast.rs:428:5 + --> tests/ui/cast.rs:429:5 | LL | (y * y * y / y * 2) as u16; | ^^^^^^^^^^^^^^^^^^^^^^^^^^ error: casting `i16` to `u16` may lose the sign of the value - --> tests/ui/cast.rs:429:5 + --> tests/ui/cast.rs:430:5 | LL | (y * y / y * 2) as u16; | ^^^^^^^^^^^^^^^^^^^^^^ error: casting `i16` to `u16` may lose the sign of the value - --> tests/ui/cast.rs:431:5 + --> tests/ui/cast.rs:432:5 | LL | (y / y * y * -2) as u16; | ^^^^^^^^^^^^^^^^^^^^^^^ error: equal expressions as operands to `/` - --> tests/ui/cast.rs:431:6 + --> tests/ui/cast.rs:432:6 | LL | (y / y * y * -2) as u16; | ^^^^^ @@ -561,97 +561,97 @@ LL | (y / y * y * -2) as u16; = note: `#[deny(clippy::eq_op)]` on by default error: casting `i16` to `u16` may lose the sign of the value - --> tests/ui/cast.rs:434:5 + --> tests/ui/cast.rs:435:5 | LL | (y + y + y + -2) as u16; | ^^^^^^^^^^^^^^^^^^^^^^^ error: casting `i16` to `u16` may lose the sign of the value - --> tests/ui/cast.rs:436:5 + --> tests/ui/cast.rs:437:5 | LL | (y + y + y + 2) as u16; | ^^^^^^^^^^^^^^^^^^^^^^ error: casting `i16` to `u16` may lose the sign of the value - --> tests/ui/cast.rs:440:5 + --> tests/ui/cast.rs:441:5 | LL | (z + -2) as u16; | ^^^^^^^^^^^^^^^ error: casting `i16` to `u16` may lose the sign of the value - --> tests/ui/cast.rs:442:5 + --> tests/ui/cast.rs:443:5 | LL | (z + z + 2) as u16; | ^^^^^^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:445:9 + --> tests/ui/cast.rs:446:9 | LL | (a * a * b * b * c * c) as u32; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:446:9 + --> tests/ui/cast.rs:447:9 | LL | (a * b * c) as u32; | ^^^^^^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:448:9 + --> tests/ui/cast.rs:449:9 | LL | (a * -b * c) as u32; | ^^^^^^^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:450:9 + --> tests/ui/cast.rs:451:9 | LL | (a * b * c * c) as u32; | ^^^^^^^^^^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:451:9 + --> tests/ui/cast.rs:452:9 | LL | (a * -2) as u32; | ^^^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:453:9 + --> tests/ui/cast.rs:454:9 | LL | (a * b * c * -2) as u32; | ^^^^^^^^^^^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:455:9 + --> tests/ui/cast.rs:456:9 | LL | (a / b) as u32; | ^^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:456:9 + --> tests/ui/cast.rs:457:9 | LL | (a / b * c) as u32; | ^^^^^^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:458:9 + --> tests/ui/cast.rs:459:9 | LL | (a / b + b * c) as u32; | ^^^^^^^^^^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:460:9 + --> tests/ui/cast.rs:461:9 | LL | a.saturating_pow(3) as u32; | ^^^^^^^^^^^^^^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:462:9 + --> tests/ui/cast.rs:463:9 | LL | (a.abs() * b.pow(2) / c.abs()) as u32 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> tests/ui/cast.rs:470:21 + --> tests/ui/cast.rs:471:21 | LL | let _ = i32::MIN as u32; // cast_sign_loss | ^^^^^^^^^^^^^^^ @@ -662,7 +662,7 @@ LL | m!(); = note: this error originates in the macro `m` (in Nightly builds, run with -Z macro-backtrace for more info) error: casting `u32` to `u8` may truncate the value - --> tests/ui/cast.rs:471:21 + --> tests/ui/cast.rs:472:21 | LL | let _ = u32::MAX as u8; // cast_possible_truncation | ^^^^^^^^^^^^^^ @@ -678,7 +678,7 @@ LL | let _ = u8::try_from(u32::MAX); // cast_possible_truncation | ~~~~~~~~~~~~~~~~~~~~~~ error: casting `f64` to `f32` may truncate the value - --> tests/ui/cast.rs:472:21 + --> tests/ui/cast.rs:473:21 | LL | let _ = std::f64::consts::PI as f32; // cast_possible_truncation | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -690,7 +690,7 @@ LL | m!(); = note: this error originates in the macro `m` (in Nightly builds, run with -Z macro-backtrace for more info) error: casting `i64` to `usize` may truncate the value on targets with 32-bit wide pointers - --> tests/ui/cast.rs:481:5 + --> tests/ui/cast.rs:482:5 | LL | bar.unwrap().unwrap() as usize | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -702,13 +702,13 @@ LL | usize::try_from(bar.unwrap().unwrap()) | error: casting `i64` to `usize` may lose the sign of the value - --> tests/ui/cast.rs:481:5 + --> tests/ui/cast.rs:482:5 | LL | bar.unwrap().unwrap() as usize | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: casting `u64` to `u8` may truncate the value - --> tests/ui/cast.rs:496:5 + --> tests/ui/cast.rs:497:5 | LL | (256 & 999999u64) as u8; | ^^^^^^^^^^^^^^^^^^^^^^^ @@ -720,7 +720,7 @@ LL | u8::try_from(256 & 999999u64); | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: casting `u64` to `u8` may truncate the value - --> tests/ui/cast.rs:498:5 + --> tests/ui/cast.rs:499:5 | LL | (255 % 999999u64) as u8; | ^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/tests/ui/unnecessary_min_or_max.fixed b/tests/ui/unnecessary_min_or_max.fixed new file mode 100644 index 000000000..392f6dd1f --- /dev/null +++ b/tests/ui/unnecessary_min_or_max.fixed @@ -0,0 +1,67 @@ +//@aux-build:external_consts.rs + +#![allow(unused)] +#![warn(clippy::unnecessary_min_or_max)] +#![allow(clippy::identity_op)] + +extern crate external_consts; + +const X: i32 = 1; + +fn main() { + // Both are Literals + let _ = (-6_i32); + let _ = 9; + let _ = 6; + let _ = 9_u32; + let _ = 6; + let _ = 7_u8; + + let x: u32 = 42; + // unsigned with zero + let _ = 0; + let _ = x; + let _ = 0_u32; + let _ = x; + + let x: i32 = 42; + // signed MIN + let _ = i32::MIN; + let _ = x; + let _ = i32::MIN; + let _ = x; + + let _ = i32::MIN - 0; + let _ = x; + + let _ = i32::MIN - 0; + + // The below cases shouldn't be lint + let mut min = u32::MAX; + for _ in 0..1000 { + min = min.min(random_u32()); + } + + let _ = 2.min(external_consts::MAGIC_NUMBER); + let _ = 2.max(external_consts::MAGIC_NUMBER); + let _ = external_consts::MAGIC_NUMBER.min(2); + let _ = external_consts::MAGIC_NUMBER.max(2); + + let _ = X.min(external_consts::MAGIC_NUMBER); + let _ = X.max(external_consts::MAGIC_NUMBER); + let _ = external_consts::MAGIC_NUMBER.min(X); + let _ = external_consts::MAGIC_NUMBER.max(X); + + let _ = X.max(12); + let _ = X.min(12); + let _ = 12.min(X); + let _ = 12.max(X); + let _ = (X + 1).max(12); + let _ = (X + 1).min(12); + let _ = 12.min(X - 1); + let _ = 12.max(X - 1); +} +fn random_u32() -> u32 { + // random number generator + 0 +} diff --git a/tests/ui/unnecessary_min_or_max.rs b/tests/ui/unnecessary_min_or_max.rs new file mode 100644 index 000000000..b03755e6d --- /dev/null +++ b/tests/ui/unnecessary_min_or_max.rs @@ -0,0 +1,67 @@ +//@aux-build:external_consts.rs + +#![allow(unused)] +#![warn(clippy::unnecessary_min_or_max)] +#![allow(clippy::identity_op)] + +extern crate external_consts; + +const X: i32 = 1; + +fn main() { + // Both are Literals + let _ = (-6_i32).min(9); + let _ = (-6_i32).max(9); + let _ = 9_u32.min(6); + let _ = 9_u32.max(6); + let _ = 6.min(7_u8); + let _ = 6.max(7_u8); + + let x: u32 = 42; + // unsigned with zero + let _ = 0.min(x); + let _ = 0.max(x); + let _ = x.min(0_u32); + let _ = x.max(0_u32); + + let x: i32 = 42; + // signed MIN + let _ = i32::MIN.min(x); + let _ = i32::MIN.max(x); + let _ = x.min(i32::MIN); + let _ = x.max(i32::MIN); + + let _ = x.min(i32::MIN - 0); + let _ = x.max(i32::MIN); + + let _ = x.min(i32::MIN - 0); + + // The below cases shouldn't be lint + let mut min = u32::MAX; + for _ in 0..1000 { + min = min.min(random_u32()); + } + + let _ = 2.min(external_consts::MAGIC_NUMBER); + let _ = 2.max(external_consts::MAGIC_NUMBER); + let _ = external_consts::MAGIC_NUMBER.min(2); + let _ = external_consts::MAGIC_NUMBER.max(2); + + let _ = X.min(external_consts::MAGIC_NUMBER); + let _ = X.max(external_consts::MAGIC_NUMBER); + let _ = external_consts::MAGIC_NUMBER.min(X); + let _ = external_consts::MAGIC_NUMBER.max(X); + + let _ = X.max(12); + let _ = X.min(12); + let _ = 12.min(X); + let _ = 12.max(X); + let _ = (X + 1).max(12); + let _ = (X + 1).min(12); + let _ = 12.min(X - 1); + let _ = 12.max(X - 1); +} +fn random_u32() -> u32 { + // random number generator + 0 +} diff --git a/tests/ui/unnecessary_min_or_max.stderr b/tests/ui/unnecessary_min_or_max.stderr new file mode 100644 index 000000000..f5cd31fba --- /dev/null +++ b/tests/ui/unnecessary_min_or_max.stderr @@ -0,0 +1,107 @@ +error: `(-6_i32)` is never greater than `9` and has therefore no effect + --> tests/ui/unnecessary_min_or_max.rs:13:13 + | +LL | let _ = (-6_i32).min(9); + | ^^^^^^^^^^^^^^^ help: try: `(-6_i32)` + | + = note: `-D clippy::unnecessary-min-or-max` implied by `-D warnings` + = help: to override `-D warnings` add `#[allow(clippy::unnecessary_min_or_max)]` + +error: `(-6_i32)` is never greater than `9` and has therefore no effect + --> tests/ui/unnecessary_min_or_max.rs:14:13 + | +LL | let _ = (-6_i32).max(9); + | ^^^^^^^^^^^^^^^ help: try: `9` + +error: `9_u32` is never smaller than `6` and has therefore no effect + --> tests/ui/unnecessary_min_or_max.rs:15:13 + | +LL | let _ = 9_u32.min(6); + | ^^^^^^^^^^^^ help: try: `6` + +error: `9_u32` is never smaller than `6` and has therefore no effect + --> tests/ui/unnecessary_min_or_max.rs:16:13 + | +LL | let _ = 9_u32.max(6); + | ^^^^^^^^^^^^ help: try: `9_u32` + +error: `6` is never greater than `7_u8` and has therefore no effect + --> tests/ui/unnecessary_min_or_max.rs:17:13 + | +LL | let _ = 6.min(7_u8); + | ^^^^^^^^^^^ help: try: `6` + +error: `6` is never greater than `7_u8` and has therefore no effect + --> tests/ui/unnecessary_min_or_max.rs:18:13 + | +LL | let _ = 6.max(7_u8); + | ^^^^^^^^^^^ help: try: `7_u8` + +error: `0` is never greater than `x` and has therefore no effect + --> tests/ui/unnecessary_min_or_max.rs:22:13 + | +LL | let _ = 0.min(x); + | ^^^^^^^^ help: try: `0` + +error: `0` is never greater than `x` and has therefore no effect + --> tests/ui/unnecessary_min_or_max.rs:23:13 + | +LL | let _ = 0.max(x); + | ^^^^^^^^ help: try: `x` + +error: `x` is never smaller than `0_u32` and has therefore no effect + --> tests/ui/unnecessary_min_or_max.rs:24:13 + | +LL | let _ = x.min(0_u32); + | ^^^^^^^^^^^^ help: try: `0_u32` + +error: `x` is never smaller than `0_u32` and has therefore no effect + --> tests/ui/unnecessary_min_or_max.rs:25:13 + | +LL | let _ = x.max(0_u32); + | ^^^^^^^^^^^^ help: try: `x` + +error: `i32::MIN` is never greater than `x` and has therefore no effect + --> tests/ui/unnecessary_min_or_max.rs:29:13 + | +LL | let _ = i32::MIN.min(x); + | ^^^^^^^^^^^^^^^ help: try: `i32::MIN` + +error: `i32::MIN` is never greater than `x` and has therefore no effect + --> tests/ui/unnecessary_min_or_max.rs:30:13 + | +LL | let _ = i32::MIN.max(x); + | ^^^^^^^^^^^^^^^ help: try: `x` + +error: `x` is never smaller than `i32::MIN` and has therefore no effect + --> tests/ui/unnecessary_min_or_max.rs:31:13 + | +LL | let _ = x.min(i32::MIN); + | ^^^^^^^^^^^^^^^ help: try: `i32::MIN` + +error: `x` is never smaller than `i32::MIN` and has therefore no effect + --> tests/ui/unnecessary_min_or_max.rs:32:13 + | +LL | let _ = x.max(i32::MIN); + | ^^^^^^^^^^^^^^^ help: try: `x` + +error: `x` is never smaller than `i32::MIN - 0` and has therefore no effect + --> tests/ui/unnecessary_min_or_max.rs:34:13 + | +LL | let _ = x.min(i32::MIN - 0); + | ^^^^^^^^^^^^^^^^^^^ help: try: `i32::MIN - 0` + +error: `x` is never smaller than `i32::MIN` and has therefore no effect + --> tests/ui/unnecessary_min_or_max.rs:35:13 + | +LL | let _ = x.max(i32::MIN); + | ^^^^^^^^^^^^^^^ help: try: `x` + +error: `x` is never smaller than `i32::MIN - 0` and has therefore no effect + --> tests/ui/unnecessary_min_or_max.rs:37:13 + | +LL | let _ = x.min(i32::MIN - 0); + | ^^^^^^^^^^^^^^^^^^^ help: try: `i32::MIN - 0` + +error: aborting due to 17 previous errors +