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| 1 | +use clippy_utils::consts::constant_simple; |
| 2 | +use clippy_utils::diagnostics::span_lint; |
| 3 | +use rustc_hir as hir; |
| 4 | +use rustc_lint::LateContext; |
| 5 | +use rustc_span::source_map::Span; |
| 6 | + |
| 7 | +use super::{FLOAT_ARITHMETIC, INTEGER_ARITHMETIC}; |
| 8 | + |
| 9 | +#[derive(Default)] |
| 10 | +pub struct Context { |
| 11 | + expr_id: Option<hir::HirId>, |
| 12 | + /// This field is used to check whether expressions are constants, such as in enum discriminants |
| 13 | + /// and consts |
| 14 | + const_span: Option<Span>, |
| 15 | +} |
| 16 | +impl Context { |
| 17 | + fn skip_expr(&mut self, e: &hir::Expr<'_>) -> bool { |
| 18 | + self.expr_id.is_some() || self.const_span.map_or(false, |span| span.contains(e.span)) |
| 19 | + } |
| 20 | + |
| 21 | + pub fn check_binary<'tcx>( |
| 22 | + &mut self, |
| 23 | + cx: &LateContext<'tcx>, |
| 24 | + expr: &'tcx hir::Expr<'_>, |
| 25 | + op: hir::BinOpKind, |
| 26 | + l: &'tcx hir::Expr<'_>, |
| 27 | + r: &'tcx hir::Expr<'_>, |
| 28 | + ) { |
| 29 | + if self.skip_expr(expr) { |
| 30 | + return; |
| 31 | + } |
| 32 | + match op { |
| 33 | + hir::BinOpKind::And |
| 34 | + | hir::BinOpKind::Or |
| 35 | + | hir::BinOpKind::BitAnd |
| 36 | + | hir::BinOpKind::BitOr |
| 37 | + | hir::BinOpKind::BitXor |
| 38 | + | hir::BinOpKind::Eq |
| 39 | + | hir::BinOpKind::Lt |
| 40 | + | hir::BinOpKind::Le |
| 41 | + | hir::BinOpKind::Ne |
| 42 | + | hir::BinOpKind::Ge |
| 43 | + | hir::BinOpKind::Gt => return, |
| 44 | + _ => (), |
| 45 | + } |
| 46 | + |
| 47 | + let (l_ty, r_ty) = (cx.typeck_results().expr_ty(l), cx.typeck_results().expr_ty(r)); |
| 48 | + if l_ty.peel_refs().is_integral() && r_ty.peel_refs().is_integral() { |
| 49 | + match op { |
| 50 | + hir::BinOpKind::Div | hir::BinOpKind::Rem => match &r.kind { |
| 51 | + hir::ExprKind::Lit(_lit) => (), |
| 52 | + hir::ExprKind::Unary(hir::UnOp::Neg, expr) => { |
| 53 | + if let hir::ExprKind::Lit(lit) = &expr.kind { |
| 54 | + if let rustc_ast::ast::LitKind::Int(1, _) = lit.node { |
| 55 | + span_lint(cx, INTEGER_ARITHMETIC, expr.span, "integer arithmetic detected"); |
| 56 | + self.expr_id = Some(expr.hir_id); |
| 57 | + } |
| 58 | + } |
| 59 | + }, |
| 60 | + _ => { |
| 61 | + span_lint(cx, INTEGER_ARITHMETIC, expr.span, "integer arithmetic detected"); |
| 62 | + self.expr_id = Some(expr.hir_id); |
| 63 | + }, |
| 64 | + }, |
| 65 | + _ => { |
| 66 | + span_lint(cx, INTEGER_ARITHMETIC, expr.span, "integer arithmetic detected"); |
| 67 | + self.expr_id = Some(expr.hir_id); |
| 68 | + }, |
| 69 | + } |
| 70 | + } else if r_ty.peel_refs().is_floating_point() && r_ty.peel_refs().is_floating_point() { |
| 71 | + span_lint(cx, FLOAT_ARITHMETIC, expr.span, "floating-point arithmetic detected"); |
| 72 | + self.expr_id = Some(expr.hir_id); |
| 73 | + } |
| 74 | + } |
| 75 | + |
| 76 | + pub fn check_negate<'tcx>(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>, arg: &'tcx hir::Expr<'_>) { |
| 77 | + if self.skip_expr(expr) { |
| 78 | + return; |
| 79 | + } |
| 80 | + let ty = cx.typeck_results().expr_ty(arg); |
| 81 | + if constant_simple(cx, cx.typeck_results(), expr).is_none() { |
| 82 | + if ty.is_integral() { |
| 83 | + span_lint(cx, INTEGER_ARITHMETIC, expr.span, "integer arithmetic detected"); |
| 84 | + self.expr_id = Some(expr.hir_id); |
| 85 | + } else if ty.is_floating_point() { |
| 86 | + span_lint(cx, FLOAT_ARITHMETIC, expr.span, "floating-point arithmetic detected"); |
| 87 | + self.expr_id = Some(expr.hir_id); |
| 88 | + } |
| 89 | + } |
| 90 | + } |
| 91 | + |
| 92 | + pub fn expr_post(&mut self, id: hir::HirId) { |
| 93 | + if Some(id) == self.expr_id { |
| 94 | + self.expr_id = None; |
| 95 | + } |
| 96 | + } |
| 97 | + |
| 98 | + pub fn enter_body(&mut self, cx: &LateContext<'_>, body: &hir::Body<'_>) { |
| 99 | + let body_owner = cx.tcx.hir().body_owner_def_id(body.id()); |
| 100 | + |
| 101 | + match cx.tcx.hir().body_owner_kind(body_owner) { |
| 102 | + hir::BodyOwnerKind::Static(_) | hir::BodyOwnerKind::Const => { |
| 103 | + let body_span = cx.tcx.def_span(body_owner); |
| 104 | + |
| 105 | + if let Some(span) = self.const_span { |
| 106 | + if span.contains(body_span) { |
| 107 | + return; |
| 108 | + } |
| 109 | + } |
| 110 | + self.const_span = Some(body_span); |
| 111 | + }, |
| 112 | + hir::BodyOwnerKind::Fn | hir::BodyOwnerKind::Closure => (), |
| 113 | + } |
| 114 | + } |
| 115 | + |
| 116 | + pub fn body_post(&mut self, cx: &LateContext<'_>, body: &hir::Body<'_>) { |
| 117 | + let body_owner = cx.tcx.hir().body_owner(body.id()); |
| 118 | + let body_span = cx.tcx.hir().span(body_owner); |
| 119 | + |
| 120 | + if let Some(span) = self.const_span { |
| 121 | + if span.contains(body_span) { |
| 122 | + return; |
| 123 | + } |
| 124 | + } |
| 125 | + self.const_span = None; |
| 126 | + } |
| 127 | +} |
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