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Added bitwise_bool lint
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‎CHANGELOG.md

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@@ -2121,6 +2121,7 @@ Released 2018-09-13
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[`await_holding_refcell_ref`]: https://rust-lang.github.io/rust-clippy/master/index.html#await_holding_refcell_ref
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[`bad_bit_mask`]: https://rust-lang.github.io/rust-clippy/master/index.html#bad_bit_mask
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[`bind_instead_of_map`]: https://rust-lang.github.io/rust-clippy/master/index.html#bind_instead_of_map
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[`bitwise_bool`]: https://rust-lang.github.io/rust-clippy/master/index.html#bitwise_bool
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[`blacklisted_name`]: https://rust-lang.github.io/rust-clippy/master/index.html#blacklisted_name
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[`blanket_clippy_restriction_lints`]: https://rust-lang.github.io/rust-clippy/master/index.html#blanket_clippy_restriction_lints
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[`blocks_in_if_conditions`]: https://rust-lang.github.io/rust-clippy/master/index.html#blocks_in_if_conditions

‎clippy_lints/src/bitwise_bool.rs

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use clippy_utils::diagnostics::span_lint_and_then;
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use clippy_utils::source::snippet_opt;
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use if_chain::if_chain;
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use rustc_errors::Applicability;
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use rustc_hir::{BinOpKind, Expr, ExprKind};
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use rustc_lint::{LateContext, LateLintPass};
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use rustc_middle::ty;
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use rustc_session::{declare_lint_pass, declare_tool_lint};
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declare_clippy_lint! {
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/// **What it does:**
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/// Checks for uses of bitwise and/or operators between booleans, eg. `x & y` or `x | y`.
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///
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/// **Why is this bad?**
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/// The bitwise operators do not support short-circuiting, so it may hinder code performance.
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/// Additionally, boolean logic "masked" as bitwise logic is not caught by lints like `unnecessary_fold`
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///
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/// **Known problems:**
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/// Boolean operators short circuit. If the programmer wishes to explicitly avoid
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/// short circuiting, then the bitwise operators could be desired.
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///
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/// **Example:**
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///
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/// ```rust
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/// if x & y {} // where both x and y are booleans
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/// ```
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/// Use instead:
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/// ```rust
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/// if x && y {}
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/// ```
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pub BITWISE_BOOL,
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correctness,
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"Boolean expressions that use bitwise rather than logical operators"
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}
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declare_lint_pass!(BitwiseBool => [BITWISE_BOOL]);
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fn is_bitwise_comparison(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
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let ty = cx.typeck_results().expr_ty(expr);
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if let (&ExprKind::Binary(ref op, _, _), &ty::Bool) = (&expr.kind, &ty.kind()) {
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op.node == BinOpKind::BitAnd || op.node == BinOpKind::BitOr
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} else {
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false
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}
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}
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fn suggession_snippet(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<String> {
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if_chain! {
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if let &ExprKind::Binary(ref op, left, right) = &expr.kind;
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if let (Some(l_snippet), Some(r_snippet)) = (snippet_opt(cx, left.span), snippet_opt(cx, right.span));
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then {
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let op_snippet = match op.node {
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BinOpKind::BitAnd => "&&",
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_ => "||",
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};
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Some(format!("{} {} {}", l_snippet, op_snippet, r_snippet))
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} else {
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None
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}
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}
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}
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impl LateLintPass<'_> for BitwiseBool {
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fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
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if is_bitwise_comparison(cx, expr) {
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span_lint_and_then(
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cx,
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BITWISE_BOOL,
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expr.span,
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"use of bitwise operator instead of logical operator between booleans",
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|diag| {
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if let Some(sugg) = suggession_snippet(cx, expr) {
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diag.span_suggestion(expr.span, "try", sugg, Applicability::MachineApplicable);
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}
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},
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);
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}
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}
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}

‎clippy_lints/src/lib.rs

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@@ -176,6 +176,7 @@ mod atomic_ordering;
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mod attrs;
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mod await_holding_invalid;
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mod bit_mask;
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mod bitwise_bool;
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mod blacklisted_name;
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mod blocks_in_if_conditions;
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mod bool_assert_comparison;
@@ -568,6 +569,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
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bit_mask::BAD_BIT_MASK,
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bit_mask::INEFFECTIVE_BIT_MASK,
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bit_mask::VERBOSE_BIT_MASK,
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bitwise_bool::BITWISE_BOOL,
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blacklisted_name::BLACKLISTED_NAME,
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blocks_in_if_conditions::BLOCKS_IN_IF_CONDITIONS,
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bool_assert_comparison::BOOL_ASSERT_COMPARISON,
@@ -1026,6 +1028,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
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let type_complexity_threshold = conf.type_complexity_threshold;
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store.register_late_pass(move || box types::Types::new(vec_box_size_threshold, type_complexity_threshold));
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store.register_late_pass(|| box booleans::NonminimalBool);
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store.register_late_pass(|| box bitwise_bool::BitwiseBool);
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store.register_late_pass(|| box eq_op::EqOp);
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store.register_late_pass(|| box enum_clike::UnportableVariant);
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store.register_late_pass(|| box float_literal::FloatLiteral);
@@ -1459,6 +1462,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
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LintId::of(attrs::USELESS_ATTRIBUTE),
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LintId::of(bit_mask::BAD_BIT_MASK),
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LintId::of(bit_mask::INEFFECTIVE_BIT_MASK),
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LintId::of(bitwise_bool::BITWISE_BOOL),
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LintId::of(blacklisted_name::BLACKLISTED_NAME),
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LintId::of(blocks_in_if_conditions::BLOCKS_IN_IF_CONDITIONS),
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LintId::of(bool_assert_comparison::BOOL_ASSERT_COMPARISON),
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LintId::of(attrs::USELESS_ATTRIBUTE),
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LintId::of(bit_mask::BAD_BIT_MASK),
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LintId::of(bit_mask::INEFFECTIVE_BIT_MASK),
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LintId::of(bitwise_bool::BITWISE_BOOL),
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LintId::of(booleans::LOGIC_BUG),
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LintId::of(casts::CAST_REF_TO_MUT),
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LintId::of(copies::IFS_SAME_COND),

‎tests/ui/bitwise_bool.fixed

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// run-rustfix
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#![warn(clippy::bitwise_bool)]
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fn returns_bool() -> bool {
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true
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}
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fn main() {
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let x = true;
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let y = false;
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if x && y {
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println!("true")
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}
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if x || y {
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println!("true")
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}
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if !x || y {
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println!("true")
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}
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if returns_bool() && x {
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println!("true")
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}
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if y && returns_bool() {
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println!("true")
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}
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if !returns_bool() && returns_bool() {
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println!("true")
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}
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}

‎tests/ui/bitwise_bool.rs

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// run-rustfix
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#![warn(clippy::bitwise_bool)]
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fn returns_bool() -> bool {
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true
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}
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fn main() {
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let x = true;
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let y = false;
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if x & y {
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println!("true")
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}
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if x | y {
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println!("true")
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}
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if !(x | y) {
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println!("true")
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}
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if returns_bool() & x {
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println!("true")
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}
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if y & returns_bool() {
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println!("true")
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}
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if !returns_bool() & returns_bool() {
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println!("true")
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}
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}

‎tests/ui/bitwise_bool.stderr

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error: use of bitwise operator instead of logical operator between booleans
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--> $DIR/bitwise_bool.rs:12:8
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|
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LL | if x & y {
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| ^^^^^ help: try: `x && y`
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|
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= note: `-D clippy::bitwise-bool` implied by `-D warnings`
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error: use of bitwise operator instead of logical operator between booleans
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--> $DIR/bitwise_bool.rs:15:8
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|
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LL | if x | y {
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| ^^^^^ help: try: `x || y`
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error: use of bitwise operator instead of logical operator between booleans
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--> $DIR/bitwise_bool.rs:18:9
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|
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LL | if !(x | y) {
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| ^^^^^^^ help: try: `x || y`
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error: use of bitwise operator instead of logical operator between booleans
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--> $DIR/bitwise_bool.rs:22:8
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|
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LL | if returns_bool() & x {
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| ^^^^^^^^^^^^^^^^^^ help: try: `returns_bool() && x`
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error: use of bitwise operator instead of logical operator between booleans
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--> $DIR/bitwise_bool.rs:25:8
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|
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LL | if y & returns_bool() {
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| ^^^^^^^^^^^^^^^^^^ help: try: `y && returns_bool()`
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error: use of bitwise operator instead of logical operator between booleans
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--> $DIR/bitwise_bool.rs:28:8
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|
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LL | if !returns_bool() & returns_bool() {
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `!returns_bool() && returns_bool()`
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error: aborting due to 6 previous errors
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