Auto merge of #12368 - vohoanglong0107:unnecessary-min, r=Alexendoo

Unnecessary call to min/max method

Continuation of https://github.com/rust-lang/rust-clippy/pull/12061
Fix https://github.com/rust-lang/rust-clippy/issues/11901 and https://github.com/rust-lang/rust-clippy/issues/11924

This implementation only deal with literal int, like `i32::MAX`, `-6_i32`, `0`

changelog: added lint [`unnecessary_min_max`]

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

clippy_lints/src/declared_lints.rs

@@ -471,6 +471,7 @@
     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,

clippy_lints/src/methods/mod.rs

@@ -117,6 +117,7 @@
 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 @@
     "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 @@ pub fn new(
     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 @@ fn check_methods<'tcx>(&self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
                     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(_))

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<Extrema> {
+    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,
+    }
+}

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::{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 @@ pub fn expr(&mut self, e: &Expr<'_>) -> Option<Constant<'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)
                 })
             },

tests/ui/auxiliary/external_consts.rs

@@ -0,0 +1 @@
+pub const MAGIC_NUMBER: i32 = 1;

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

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;
    |     ^^^^^^^^^^^^^^^^^^^^^^^

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
+}

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
+}

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
+