rebase, clean-up import, add negative cases for signed integers

Author: alv-around

clippy_lints/src/lib.rs

@@ -736,7 +736,7 @@ rustc_lint::late_lint_methods!(
         NeedlessLateInit: needless_late_init::NeedlessLateInit = needless_late_init::NeedlessLateInit,
         ReturnSelfNotMustUse: return_self_not_must_use::ReturnSelfNotMustUse = return_self_not_must_use::ReturnSelfNotMustUse,
         NumberedFields: init_numbered_fields::NumberedFields = init_numbered_fields::NumberedFields,
-        ManualBitWidth: manual_bit_width::ManualBits = manual_bit_width::ManualBitWidth::new(conf),
+        ManualBitWidth: manual_bit_width::ManualBitWidth = manual_bit_width::ManualBitWidth::new(conf),
         ManualBits: manual_bits::ManualBits = manual_bits::ManualBits::new(conf),
         DefaultUnionRepresentation: default_union_representation::DefaultUnionRepresentation = default_union_representation::DefaultUnionRepresentation,
         OnlyUsedInRecursion: only_used_in_recursion::OnlyUsedInRecursion = <only_used_in_recursion::OnlyUsedInRecursion>::default(),

clippy_lints/src/manual_bit_width.rs

@@ -54,8 +54,7 @@ impl LateLintPass<'_> for ManualBitWidth {
         match expr.kind {
             // `T::BITS - n.leading_zeros()`
             ExprKind::Binary(op, left, right)
-                if left.span.eq_ctxt(right.span)
-                    && op.node == BinOpKind::Sub
+                if op.node == BinOpKind::Sub
                     && let ExprKind::MethodCall(leading_zeros, recv, [], _) = right.kind
                     && leading_zeros.ident.name == sym::leading_zeros
                     && let ExprKind::Path(QPath::TypeRelative(hir_ty, segment)) = left.kind
@@ -74,6 +73,7 @@ impl LateLintPass<'_> for ManualBitWidth {
                         _ => return,
                     }
                     && self.msrv.meets(cx, msrvs::BIT_WIDTH)
+                    && left.span.eq_ctxt(right.span)
                     && !is_from_proc_macro(cx, expr) =>
             {
                 emit(cx, recv, expr);
@@ -90,7 +90,7 @@ fn emit(cx: &LateContext<'_>, recv: &Expr<'_>, full_expr: &Expr<'_>) {
         cx,
         MANUAL_BIT_WIDTH,
         full_expr.span,
-        "manually reimplementing `bit_width`",
+        "manual implementation of `bit_width`",
         "try",
         format!("{recv_snip}.bit_width()"),
         app,

tests/ui/manual_bit_width.fixed

@@ -1,8 +1,5 @@
 #![warn(clippy::manual_bit_width)]
 
-use core::num::NonZero;
-use std::num;
-
 fn main() {
     let x: u32 = 5;
 
@@ -13,5 +10,12 @@ fn main() {
     let _ = x.bit_width(); //~ manual_bit_width
     let _ = x.bit_width(); //~ manual_bit_width
 
+    // negative cases.
     let _ = 128 - x.leading_zeros();
+
+    // signed integers do not implement `bit_width()`
+    let _ = i8::BITS - x.leading_zeros();
+    let _ = i16::BITS - x.leading_zeros();
+    let _ = i32::BITS - x.leading_zeros();
+    let _ = i64::BITS - x.leading_zeros();
 }

tests/ui/manual_bit_width.rs

@@ -1,8 +1,5 @@
 #![warn(clippy::manual_bit_width)]
 
-use core::num::NonZero;
-use std::num;
-
 fn main() {
     let x: u32 = 5;
 
@@ -13,5 +10,12 @@ fn main() {
     let _ = u64::BITS - x.leading_zeros(); //~ manual_bit_width
     let _ = usize::BITS - x.leading_zeros(); //~ manual_bit_width
 
+    // negative cases.
     let _ = 128 - x.leading_zeros();
+
+    // signed integers do not implement `bit_width()`
+    let _ = i8::BITS - x.leading_zeros();
+    let _ = i16::BITS - x.leading_zeros();
+    let _ = i32::BITS - x.leading_zeros();
+    let _ = i64::BITS - x.leading_zeros();
 }

tests/ui/manual_bit_width.stderr

@@ -1,32 +1,32 @@
-error: manually reimplementing `bit_width`
-  --> tests/ui/manual_bit_width.rs:10:13
+error: manual implementation of `bit_width`
+  --> tests/ui/manual_bit_width.rs:7:13
    |
 LL |     let _ = u8::BITS - x.leading_zeros();
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `x.bit_width()`
    |
    = note: `-D clippy::manual-bit-width` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::manual_bit_width)]`
 
-error: manually reimplementing `bit_width`
-  --> tests/ui/manual_bit_width.rs:11:13
+error: manual implementation of `bit_width`
+  --> tests/ui/manual_bit_width.rs:8:13
    |
 LL |     let _ = u16::BITS - x.leading_zeros();
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `x.bit_width()`
 
-error: manually reimplementing `bit_width`
-  --> tests/ui/manual_bit_width.rs:12:13
+error: manual implementation of `bit_width`
+  --> tests/ui/manual_bit_width.rs:9:13
    |
 LL |     let _ = u32::BITS - x.leading_zeros();
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `x.bit_width()`
 
-error: manually reimplementing `bit_width`
-  --> tests/ui/manual_bit_width.rs:13:13
+error: manual implementation of `bit_width`
+  --> tests/ui/manual_bit_width.rs:10:13
    |
 LL |     let _ = u64::BITS - x.leading_zeros();
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `x.bit_width()`
 
-error: manually reimplementing `bit_width`
-  --> tests/ui/manual_bit_width.rs:14:13
+error: manual implementation of `bit_width`
+  --> tests/ui/manual_bit_width.rs:11:13
    |
 LL |     let _ = usize::BITS - x.leading_zeros();
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `x.bit_width()`