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Auto merge of #5365 - mgr-inz-rafal:issue4983_bool_updates, r=yaahc
Issue4983 bool updates changelog: Check for bool inequality comparison that might be written more concisely Fixes #4983
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42c36dc77b
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@ -3,13 +3,15 @@
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//! This lint is **warn** by default
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use crate::utils::sugg::Sugg;
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use crate::utils::{higher, parent_node_is_if_expr, span_lint, span_lint_and_sugg};
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use crate::utils::{higher, parent_node_is_if_expr, snippet_with_applicability, span_lint, span_lint_and_sugg};
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use if_chain::if_chain;
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use rustc_ast::ast::LitKind;
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use rustc_errors::Applicability;
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use rustc_hir::{BinOpKind, Block, Expr, ExprKind, StmtKind};
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use rustc_hir::{BinOpKind, Block, Expr, ExprKind, StmtKind, UnOp};
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use rustc_lint::{LateContext, LateLintPass};
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use rustc_session::{declare_lint_pass, declare_tool_lint};
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use rustc_span::source_map::Spanned;
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use rustc_span::Span;
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declare_clippy_lint! {
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/// **What it does:** Checks for expressions of the form `if c { true } else {
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@ -188,6 +190,34 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for BoolComparison {
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}
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}
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struct ExpressionInfoWithSpan {
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one_side_is_unary_not: bool,
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left_span: Span,
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right_span: Span,
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}
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fn is_unary_not(e: &Expr<'_>) -> (bool, Span) {
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if_chain! {
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if let ExprKind::Unary(unop, operand) = e.kind;
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if let UnOp::UnNot = unop;
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then {
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return (true, operand.span);
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}
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};
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(false, e.span)
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}
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fn one_side_is_unary_not<'tcx>(left_side: &'tcx Expr<'_>, right_side: &'tcx Expr<'_>) -> ExpressionInfoWithSpan {
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let left = is_unary_not(left_side);
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let right = is_unary_not(right_side);
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ExpressionInfoWithSpan {
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one_side_is_unary_not: left.0 != right.0,
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left_span: left.1,
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right_span: right.1,
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}
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}
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fn check_comparison<'a, 'tcx>(
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cx: &LateContext<'a, 'tcx>,
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e: &'tcx Expr<'_>,
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@ -199,10 +229,30 @@ fn check_comparison<'a, 'tcx>(
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) {
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use self::Expression::{Bool, Other};
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if let ExprKind::Binary(_, ref left_side, ref right_side) = e.kind {
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if let ExprKind::Binary(op, ref left_side, ref right_side) = e.kind {
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let (l_ty, r_ty) = (cx.tables.expr_ty(left_side), cx.tables.expr_ty(right_side));
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if l_ty.is_bool() && r_ty.is_bool() {
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let mut applicability = Applicability::MachineApplicable;
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if let BinOpKind::Eq = op.node {
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let expression_info = one_side_is_unary_not(&left_side, &right_side);
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if expression_info.one_side_is_unary_not {
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span_lint_and_sugg(
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cx,
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BOOL_COMPARISON,
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e.span,
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"This comparison might be written more concisely",
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"try simplifying it as shown",
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format!(
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"{} != {}",
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snippet_with_applicability(cx, expression_info.left_span, "..", &mut applicability),
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snippet_with_applicability(cx, expression_info.right_span, "..", &mut applicability)
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),
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applicability,
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)
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}
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}
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match (fetch_bool_expr(left_side), fetch_bool_expr(right_side)) {
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(Bool(true), Other) => left_true.map_or((), |(h, m)| {
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suggest_bool_comparison(cx, e, right_side, applicability, m, h)
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@ -111,3 +111,19 @@ fn issue3703() {
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if Foo < false {}
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if false < Foo {}
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}
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#[allow(dead_code)]
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fn issue4983() {
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let a = true;
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let b = false;
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if a != b {};
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if a != b {};
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if a == b {};
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if !a == !b {};
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if b != a {};
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if b != a {};
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if b == a {};
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if !b == !a {};
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}
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@ -111,3 +111,19 @@ fn issue3703() {
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if Foo < false {}
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if false < Foo {}
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}
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#[allow(dead_code)]
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fn issue4983() {
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let a = true;
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let b = false;
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if a == !b {};
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if !a == b {};
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if a == b {};
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if !a == !b {};
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if b == !a {};
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if !b == a {};
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if b == a {};
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if !b == !a {};
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}
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@ -84,5 +84,29 @@ error: order comparisons between booleans can be simplified
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LL | if x > y {
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| ^^^^^ help: try simplifying it as shown: `x & !y`
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error: aborting due to 14 previous errors
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error: This comparison might be written more concisely
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--> $DIR/bool_comparison.rs:120:8
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LL | if a == !b {};
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| ^^^^^^^ help: try simplifying it as shown: `a != b`
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error: This comparison might be written more concisely
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--> $DIR/bool_comparison.rs:121:8
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LL | if !a == b {};
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| ^^^^^^^ help: try simplifying it as shown: `a != b`
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error: This comparison might be written more concisely
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--> $DIR/bool_comparison.rs:125:8
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LL | if b == !a {};
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| ^^^^^^^ help: try simplifying it as shown: `b != a`
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error: This comparison might be written more concisely
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--> $DIR/bool_comparison.rs:126:8
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LL | if !b == a {};
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| ^^^^^^^ help: try simplifying it as shown: `b != a`
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error: aborting due to 18 previous errors
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