Auto merge of #81993 - flip1995:clippyup, r=Manishearth

[rust.git] / clippy_lints / src / erasing_op.rs

diff --git a/clippy_lints/src/erasing_op.rs b/clippy_lints/src/erasing_op.rs
index e2725cf59b08926a12de417a8ac417522de61d09..dbd1ff514f0e13292b6d7a8a0aa2efc7b2e220d6 100644 (file)
--- a/clippy_lints/src/erasing_op.rs
+++ b/clippy_lints/src/erasing_op.rs
@@ -1,54 +1,40 @@
-// 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 rustc_hir::{BinOpKind, Expr, ExprKind};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::source_map::Span;
 
 use crate::consts::{constant_simple, Constant};
-use crate::rustc::hir::*;
-use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use crate::rustc::{declare_tool_lint, lint_array};
-use crate::syntax::source_map::Span;
-use crate::utils::{in_macro, span_lint};
+use crate::utils::span_lint;
 
-/// **What it does:** Checks for erasing operations, e.g. `x * 0`.
-///
-/// **Why is this bad?** The whole expression can be replaced by zero.
-/// This is most likely not the intended outcome and should probably be
-/// corrected
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// 0 / x;
-/// 0 * x;
-/// x & 0
-/// ```
 declare_clippy_lint! {
+    /// **What it does:** Checks for erasing operations, e.g., `x * 0`.
+    ///
+    /// **Why is this bad?** The whole expression can be replaced by zero.
+    /// This is most likely not the intended outcome and should probably be
+    /// corrected
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Example:**
+    /// ```rust
+    /// let x = 1;
+    /// 0 / x;
+    /// 0 * x;
+    /// x & 0;
+    /// ```
     pub ERASING_OP,
     correctness,
-    "using erasing operations, e.g. `x * 0` or `y & 0`"
+    "using erasing operations, e.g., `x * 0` or `y & 0`"
 }
 
-#[derive(Copy, Clone)]
-pub struct ErasingOp;
+declare_lint_pass!(ErasingOp => [ERASING_OP]);
 
-impl LintPass for ErasingOp {
-    fn get_lints(&self) -> LintArray {
-        lint_array!(ERASING_OP)
-    }
-}
-
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ErasingOp {
-    fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
-        if in_macro(e.span) {
+impl<'tcx> LateLintPass<'tcx> for ErasingOp {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
+        if e.span.from_expansion() {
             return;
         }
-        if let ExprKind::Binary(ref cmp, ref left, ref right) = e.node {
+        if let ExprKind::Binary(ref cmp, ref left, ref right) = e.kind {
             match cmp.node {
                 BinOpKind::Mul | BinOpKind::BitAnd => {
                     check(cx, left, e.span);
@@ -61,15 +47,13 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
     }
 }
 
-fn check(cx: &LateContext<'_, '_>, e: &Expr, span: Span) {
-    if let Some(Constant::Int(v)) = constant_simple(cx, cx.tables, e) {
-        if v == 0 {
-            span_lint(
-                cx,
-                ERASING_OP,
-                span,
-                "this operation will always return zero. This is likely not the intended outcome",
-            );
-        }
+fn check(cx: &LateContext<'_>, e: &Expr<'_>, span: Span) {
+    if let Some(Constant::Int(0)) = constant_simple(cx, cx.typeck_results(), e) {
+        span_lint(
+            cx,
+            ERASING_OP,
+            span,
+            "this operation will always return zero. This is likely not the intended outcome",
+        );
     }
 }