]> git.lizzy.rs Git - rust.git/blobdiff - clippy_lints/src/arithmetic.rs
Auto merge of #4938 - flip1995:rustup, r=flip1995
[rust.git] / clippy_lints / src / arithmetic.rs
index 4d7e921567d65b059d858a855c86bdec0474c6b5..7653ba43459f2db068f24be9a778f71b2d65745c 100644 (file)
@@ -1,49 +1,43 @@
-// 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 crate::consts::constant_simple;
 use crate::utils::span_lint;
-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 rustc::hir;
+use rustc::impl_lint_pass;
+use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use rustc_session::declare_tool_lint;
+use syntax::source_map::Span;
 
-/// **What it does:** Checks for plain integer arithmetic.
-///
-/// **Why is this bad?** This is only checked against overflow in debug builds.
-/// In some applications one wants explicitly checked, wrapping or saturating
-/// arithmetic.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// a + 1
-/// ```
 declare_clippy_lint! {
+    /// **What it does:** Checks for plain integer arithmetic.
+    ///
+    /// **Why is this bad?** This is only checked against overflow in debug builds.
+    /// In some applications one wants explicitly checked, wrapping or saturating
+    /// arithmetic.
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Example:**
+    /// ```rust
+    /// # let a = 0;
+    /// a + 1;
+    /// ```
     pub INTEGER_ARITHMETIC,
     restriction,
     "any integer arithmetic statement"
 }
 
-/// **What it does:** Checks for float arithmetic.
-///
-/// **Why is this bad?** For some embedded systems or kernel development, it
-/// can be useful to rule out floating-point numbers.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// a + 1.0
-/// ```
 declare_clippy_lint! {
+    /// **What it does:** Checks for float arithmetic.
+    ///
+    /// **Why is this bad?** For some embedded systems or kernel development, it
+    /// can be useful to rule out floating-point numbers.
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Example:**
+    /// ```rust
+    /// # let a = 0.0;
+    /// a + 1.0;
+    /// ```
     pub FLOAT_ARITHMETIC,
     restriction,
     "any floating-point arithmetic statement"
 
 #[derive(Copy, Clone, Default)]
 pub struct Arithmetic {
-    span: Option<Span>,
+    expr_span: Option<Span>,
+    /// This field is used to check whether expressions are constants, such as in enum discriminants
+    /// and consts
+    const_span: Option<Span>,
 }
 
-impl LintPass for Arithmetic {
-    fn get_lints(&self) -> LintArray {
-        lint_array!(INTEGER_ARITHMETIC, FLOAT_ARITHMETIC)
-    }
-}
+impl_lint_pass!(Arithmetic => [INTEGER_ARITHMETIC, FLOAT_ARITHMETIC]);
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Arithmetic {
     fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr) {
-        if self.span.is_some() {
+        if self.expr_span.is_some() {
             return;
         }
-        match expr.node {
-            hir::ExprKind::Binary(ref op, ref l, ref r) => {
+
+        if let Some(span) = self.const_span {
+            if span.contains(expr.span) {
+                return;
+            }
+        }
+        match &expr.kind {
+            hir::ExprKind::Binary(op, l, r) | hir::ExprKind::AssignOp(op, l, r) => {
                 match op.node {
                     hir::BinOpKind::And
                     | hir::BinOpKind::Or
@@ -86,20 +85,22 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr) {
                 let (l_ty, r_ty) = (cx.tables.expr_ty(l), cx.tables.expr_ty(r));
                 if l_ty.is_integral() && r_ty.is_integral() {
                     span_lint(cx, INTEGER_ARITHMETIC, expr.span, "integer arithmetic detected");
-                    self.span = Some(expr.span);
+                    self.expr_span = Some(expr.span);
                 } else if l_ty.is_floating_point() && r_ty.is_floating_point() {
                     span_lint(cx, FLOAT_ARITHMETIC, expr.span, "floating-point arithmetic detected");
-                    self.span = Some(expr.span);
+                    self.expr_span = Some(expr.span);
                 }
             },
-            hir::ExprKind::Unary(hir::UnOp::UnNeg, ref arg) => {
+            hir::ExprKind::Unary(hir::UnOp::UnNeg, arg) => {
                 let ty = cx.tables.expr_ty(arg);
-                if ty.is_integral() {
-                    span_lint(cx, INTEGER_ARITHMETIC, expr.span, "integer arithmetic detected");
-                    self.span = Some(expr.span);
-                } else if ty.is_floating_point() {
-                    span_lint(cx, FLOAT_ARITHMETIC, expr.span, "floating-point arithmetic detected");
-                    self.span = Some(expr.span);
+                if constant_simple(cx, cx.tables, expr).is_none() {
+                    if ty.is_integral() {
+                        span_lint(cx, INTEGER_ARITHMETIC, expr.span, "integer arithmetic detected");
+                        self.expr_span = Some(expr.span);
+                    } else if ty.is_floating_point() {
+                        span_lint(cx, FLOAT_ARITHMETIC, expr.span, "floating-point arithmetic detected");
+                        self.expr_span = Some(expr.span);
+                    }
                 }
             },
             _ => (),
@@ -107,8 +108,38 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr) {
     }
 
     fn check_expr_post(&mut self, _: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr) {
-        if Some(expr.span) == self.span {
-            self.span = None;
+        if Some(expr.span) == self.expr_span {
+            self.expr_span = None;
+        }
+    }
+
+    fn check_body(&mut self, cx: &LateContext<'_, '_>, body: &hir::Body<'_>) {
+        let body_owner = cx.tcx.hir().body_owner(body.id());
+
+        match cx.tcx.hir().body_owner_kind(body_owner) {
+            hir::BodyOwnerKind::Static(_) | hir::BodyOwnerKind::Const => {
+                let body_span = cx.tcx.hir().span(body_owner);
+
+                if let Some(span) = self.const_span {
+                    if span.contains(body_span) {
+                        return;
+                    }
+                }
+                self.const_span = Some(body_span);
+            },
+            hir::BodyOwnerKind::Fn | hir::BodyOwnerKind::Closure => (),
+        }
+    }
+
+    fn check_body_post(&mut self, cx: &LateContext<'_, '_>, body: &hir::Body<'_>) {
+        let body_owner = cx.tcx.hir().body_owner(body.id());
+        let body_span = cx.tcx.hir().span(body_owner);
+
+        if let Some(span) = self.const_span {
+            if span.contains(body_span) {
+                return;
+            }
         }
+        self.const_span = None;
     }
 }