| use crate::consts::constant_simple; |
| use crate::utils::span_lint; |
| use rustc_hir as hir; |
| use rustc_lint::{LateContext, LateLintPass}; |
| use rustc_session::{declare_tool_lint, impl_lint_pass}; |
| use rustc_span::source_map::Span; |
| |
| declare_clippy_lint! { |
| /// **What it does:** Checks for integer arithmetic operations which could overflow or panic. |
| /// |
| /// Specifically, checks for any operators (`+`, `-`, `*`, `<<`, etc) which are capable |
| /// of overflowing according to the [Rust |
| /// Reference](https://doc.rust-lang.org/reference/expressions/operator-expr.html#overflow), |
| /// or which can panic (`/`, `%`). No bounds analysis or sophisticated reasoning is |
| /// attempted. |
| /// |
| /// **Why is this bad?** Integer overflow will trigger a panic in debug builds or will wrap in |
| /// release mode. Division by zero will cause a panic in either mode. 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 expression which could overflow or panic" |
| } |
| |
| 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 { |
| 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_lint_pass!(Arithmetic => [INTEGER_ARITHMETIC, FLOAT_ARITHMETIC]); |
| |
| impl<'tcx> LateLintPass<'tcx> for Arithmetic { |
| fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) { |
| if self.expr_span.is_some() { |
| return; |
| } |
| |
| 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 |
| | hir::BinOpKind::BitAnd |
| | hir::BinOpKind::BitOr |
| | hir::BinOpKind::BitXor |
| | hir::BinOpKind::Eq |
| | hir::BinOpKind::Lt |
| | hir::BinOpKind::Le |
| | hir::BinOpKind::Ne |
| | hir::BinOpKind::Ge |
| | hir::BinOpKind::Gt => return, |
| _ => (), |
| } |
| |
| let (l_ty, r_ty) = (cx.tables().expr_ty(l), cx.tables().expr_ty(r)); |
| if l_ty.peel_refs().is_integral() && r_ty.peel_refs().is_integral() { |
| span_lint(cx, INTEGER_ARITHMETIC, expr.span, "integer arithmetic detected"); |
| self.expr_span = Some(expr.span); |
| } else if l_ty.peel_refs().is_floating_point() && r_ty.peel_refs().is_floating_point() { |
| span_lint(cx, FLOAT_ARITHMETIC, expr.span, "floating-point arithmetic detected"); |
| self.expr_span = Some(expr.span); |
| } |
| }, |
| hir::ExprKind::Unary(hir::UnOp::UnNeg, arg) => { |
| let ty = cx.tables().expr_ty(arg); |
| 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); |
| } |
| } |
| }, |
| _ => (), |
| } |
| } |
| |
| fn check_expr_post(&mut self, _: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) { |
| 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; |
| } |
| } |