3 use rustc::hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
5 use utils::{get_trait_def_id, span_lint};
7 /// **What it does:** Lints for suspicious operations in impls of arithmetic operators, e.g.
8 /// subtracting elements in an Add impl.
10 /// **Why this is bad?** This is probably a typo or copy-and-paste error and not intended.
12 /// **Known problems:** None.
16 /// impl Add for Foo {
17 /// type Output = Foo;
19 /// fn add(self, other: Foo) -> Foo {
20 /// Foo(self.0 - other.0)
25 pub SUSPICIOUS_ARITHMETIC_IMPL,
27 "suspicious use of operators in impl of arithmetic trait"
30 /// **What it does:** Lints for suspicious operations in impls of OpAssign, e.g.
31 /// subtracting elements in an AddAssign impl.
33 /// **Why this is bad?** This is probably a typo or copy-and-paste error and not intended.
35 /// **Known problems:** None.
39 /// impl AddAssign for Foo {
40 /// fn add_assign(&mut self, other: Foo) {
41 /// *self = *self - other;
46 pub SUSPICIOUS_OP_ASSIGN_IMPL,
48 "suspicious use of operators in impl of OpAssign trait"
51 #[derive(Copy, Clone)]
52 pub struct SuspiciousImpl;
54 impl LintPass for SuspiciousImpl {
55 fn get_lints(&self) -> LintArray {
56 lint_array![SUSPICIOUS_ARITHMETIC_IMPL, SUSPICIOUS_OP_ASSIGN_IMPL]
60 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for SuspiciousImpl {
61 fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr) {
62 use rustc::hir::BinOp_::*;
63 if let hir::ExprBinary(binop, _, _) = expr.node {
65 BiEq | BiLt | BiLe | BiNe | BiGe | BiGt => return,
68 // Check if the binary expression is part of another bi/unary expression
70 let mut parent_expr = cx.tcx.hir.get_parent_node(expr.id);
71 while parent_expr != ast::CRATE_NODE_ID {
72 if let hir::map::Node::NodeExpr(e) = cx.tcx.hir.get(parent_expr) {
75 | hir::ExprUnary(hir::UnOp::UnNot, _)
76 | hir::ExprUnary(hir::UnOp::UnNeg, _) => return,
80 parent_expr = cx.tcx.hir.get_parent_node(parent_expr);
83 let mut visitor = BinaryExprVisitor {
84 in_binary_expr: false,
86 walk_expr(&mut visitor, expr);
88 if visitor.in_binary_expr {
92 if let Some(impl_trait) = check_binop(
96 &["Add", "Sub", "Mul", "Div"],
97 &[BiAdd, BiSub, BiMul, BiDiv],
101 SUSPICIOUS_ARITHMETIC_IMPL,
104 r#"Suspicious use of binary operator in `{}` impl"#,
110 if let Some(impl_trait) = check_binop(
127 BiAdd, BiSub, BiMul, BiDiv, BiBitAnd, BiBitOr, BiBitXor, BiRem, BiShl, BiShr
132 SUSPICIOUS_OP_ASSIGN_IMPL,
135 r#"Suspicious use of binary operator in `{}` impl"#,
149 expected_ops: &[hir::BinOp_],
150 ) -> Option<&'a str> {
151 let mut trait_ids = vec![];
152 let [krate, module] = ::utils::paths::OPS_MODULE;
155 let path = [krate, module, t];
156 if let Some(trait_id) = get_trait_def_id(cx, &path) {
157 trait_ids.push(trait_id);
163 // Get the actually implemented trait
164 let parent_fn = cx.tcx.hir.get_parent(expr.id);
165 let parent_impl = cx.tcx.hir.get_parent(parent_fn);
168 if parent_impl != ast::CRATE_NODE_ID;
169 if let hir::map::Node::NodeItem(item) = cx.tcx.hir.get(parent_impl);
170 if let hir::Item_::ItemImpl(_, _, _, _, Some(ref trait_ref), _, _) = item.node;
171 if let Some(idx) = trait_ids.iter().position(|&tid| tid == trait_ref.path.def.def_id());
172 if *binop != expected_ops[idx];
174 return Some(traits[idx])
181 struct BinaryExprVisitor {
182 in_binary_expr: bool,
185 impl<'a, 'tcx: 'a> Visitor<'tcx> for BinaryExprVisitor {
186 fn visit_expr(&mut self, expr: &'tcx hir::Expr) {
189 | hir::ExprUnary(hir::UnOp::UnNot, _)
190 | hir::ExprUnary(hir::UnOp::UnNeg, _) => {
191 self.in_binary_expr = true
196 walk_expr(self, expr);
198 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
199 NestedVisitorMap::None