Auto merge of #3946 - rchaser53:issue-3920, r=flip1995

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

diff --git a/clippy_lints/src/arithmetic.rs b/clippy_lints/src/arithmetic.rs
index 4ad2c43e0836bb95dd348107c8f679b1ae792b19..416ec656e12a44bb5d1729f15e2c413c46ddb176 100644 (file)
--- a/clippy_lints/src/arithmetic.rs
+++ b/clippy_lints/src/arithmetic.rs
@@ -1,39 +1,40 @@
+use crate::consts::constant_simple;
 use crate::utils::span_lint;
 use rustc::hir;
 use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
 use rustc::{declare_tool_lint, lint_array};
 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
+    /// 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
+    /// a + 1.0
+    /// ```
     pub FLOAT_ARITHMETIC,
     restriction,
     "any floating-point arithmetic statement"
@@ -51,6 +52,10 @@ impl LintPass for Arithmetic {
     fn get_lints(&self) -> LintArray {
         lint_array!(INTEGER_ARITHMETIC, FLOAT_ARITHMETIC)
     }
+
+    fn name(&self) -> &'static str {
+        "Arithmetic"
+    }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Arithmetic {
@@ -92,7 +97,13 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr) {
                 }
             },
             hir::ExprKind::Unary(hir::UnOp::UnNeg, arg) => {
-                if cx.tables.expr_ty(arg).is_floating_point() {
+                let ty = cx.tables.expr_ty(arg);
+                if ty.is_integral() {
+                    if constant_simple(cx, cx.tables, expr).is_none() {
+                        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);
                 }
@@ -121,7 +132,7 @@ fn check_body(&mut self, cx: &LateContext<'_, '_>, body: &hir::Body) {
                 }
                 self.const_span = Some(body_span);
             },
-            hir::BodyOwnerKind::Fn => (),
+            hir::BodyOwnerKind::Fn | hir::BodyOwnerKind::Closure => (),
         }
     }