use rustc::hir; use rustc::lint::*; use syntax::codemap::Span; use crate::utils::span_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 /// ``` declare_clippy_lint! { 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! { pub FLOAT_ARITHMETIC, restriction, "any floating-point arithmetic statement" } #[derive(Copy, Clone, Default)] pub struct Arithmetic { span: Option, } impl LintPass for Arithmetic { fn get_lints(&self) -> LintArray { lint_array!(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() { return; } match expr.node { hir::ExprBinary(ref op, ref l, ref r) => { match op.node { hir::BiAnd | hir::BiOr | hir::BiBitAnd | hir::BiBitOr | hir::BiBitXor | hir::BiShl | hir::BiShr | hir::BiEq | hir::BiLt | hir::BiLe | hir::BiNe | hir::BiGe | hir::BiGt => return, _ => (), } 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); } 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); } }, hir::ExprUnary(hir::UnOp::UnNeg, ref 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); } }, _ => (), } } fn check_expr_post(&mut self, _: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr) { if Some(expr.span) == self.span { self.span = None; } } }