-// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
use if_chain::if_chain;
-use rustc::hir::*;
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
-use syntax::source_map::{Span, Spanned};
+use rustc_hir::{BinOpKind, Expr, ExprKind, UnOp};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::source_map::Span;
use crate::consts::{self, Constant};
use crate::utils::span_lint;
-/// **What it does:** Checks for multiplication by -1 as a form of negation.
-///
-/// **Why is this bad?** It's more readable to just negate.
-///
-/// **Known problems:** This only catches integers (for now).
-///
-/// **Example:**
-/// ```rust
-/// x * -1
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for multiplication by -1 as a form of negation.
+ ///
+ /// **Why is this bad?** It's more readable to just negate.
+ ///
+ /// **Known problems:** This only catches integers (for now).
+ ///
+ /// **Example:**
+ /// ```ignore
+ /// x * -1
+ /// ```
pub NEG_MULTIPLY,
style,
- "multiplying integers with -1"
+ "multiplying integers with `-1`"
}
-#[derive(Copy, Clone)]
-pub struct NegMultiply;
-
-impl LintPass for NegMultiply {
- fn get_lints(&self) -> LintArray {
- lint_array!(NEG_MULTIPLY)
- }
-}
+declare_lint_pass!(NegMultiply => [NEG_MULTIPLY]);
#[allow(clippy::match_same_arms)]
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NegMultiply {
- fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
- if let ExprKind::Binary(
- Spanned {
- node: BinOpKind::Mul, ..
- },
- ref l,
- ref r,
- ) = e.node
- {
- match (&l.node, &r.node) {
- (&ExprKind::Unary(..), &ExprKind::Unary(..)) => (),
- (&ExprKind::Unary(UnNeg, ref lit), _) => check_mul(cx, e.span, lit, r),
- (_, &ExprKind::Unary(UnNeg, ref lit)) => check_mul(cx, e.span, lit, l),
- _ => (),
+impl<'tcx> LateLintPass<'tcx> for NegMultiply {
+ fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
+ if let ExprKind::Binary(ref op, ref left, ref right) = e.kind {
+ if BinOpKind::Mul == op.node {
+ match (&left.kind, &right.kind) {
+ (&ExprKind::Unary(..), &ExprKind::Unary(..)) => {},
+ (&ExprKind::Unary(UnOp::Neg, ref lit), _) => check_mul(cx, e.span, lit, right),
+ (_, &ExprKind::Unary(UnOp::Neg, ref lit)) => check_mul(cx, e.span, lit, left),
+ _ => {},
+ }
}
}
}
}
-fn check_mul(cx: &LateContext<'_, '_>, span: Span, lit: &Expr, exp: &Expr) {
+fn check_mul(cx: &LateContext<'_>, span: Span, lit: &Expr<'_>, exp: &Expr<'_>) {
if_chain! {
- if let ExprKind::Lit(ref l) = lit.node;
- if let Constant::Int(val) = consts::lit_to_constant(&l.node, cx.tables.expr_ty(lit));
- if val == 1;
- if cx.tables.expr_ty(exp).is_integral();
+ if let ExprKind::Lit(ref l) = lit.kind;
+ if let Constant::Int(1) = consts::lit_to_constant(&l.node, cx.typeck_results().expr_ty_opt(lit));
+ if cx.typeck_results().expr_ty(exp).is_integral();
then {
- span_lint(cx,
- NEG_MULTIPLY,
- span,
- "Negation by multiplying with -1");
+ span_lint(cx, NEG_MULTIPLY, span, "negation by multiplying with `-1`");
}
}
}