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 {
64 // Check if the binary expression is part of another binary expression
66 let mut parent_expr = cx.tcx.hir.get_parent_node(expr.id);
67 while parent_expr != ast::CRATE_NODE_ID {
69 if let hir::map::Node::NodeExpr(e) = cx.tcx.hir.get(parent_expr);
70 if let hir::ExprBinary(_, _, _) = e.node;
76 parent_expr = cx.tcx.hir.get_parent_node(parent_expr);
79 let mut visitor = BinaryExprVisitor {
80 in_binary_expr: false,
82 walk_expr(&mut visitor, expr);
84 if visitor.in_binary_expr {
88 if let Some(impl_trait) = check_binop(
92 &["Add", "Sub", "Mul", "Div"],
93 &[BiAdd, BiSub, BiMul, BiDiv],
97 SUSPICIOUS_ARITHMETIC_IMPL,
100 r#"Suspicious use of binary operator in `{}` impl"#,
106 if let Some(impl_trait) = check_binop(
123 BiAdd, BiSub, BiMul, BiDiv, BiBitAnd, BiBitOr, BiBitXor, BiRem, BiShl, BiShr
128 SUSPICIOUS_OP_ASSIGN_IMPL,
131 r#"Suspicious use of binary operator in `{}` impl"#,
145 expected_ops: &[hir::BinOp_],
146 ) -> Option<&'a str> {
147 let mut trait_ids = vec![];
148 let [krate, module] = ::utils::paths::OPS_MODULE;
151 let path = [krate, module, t];
152 if let Some(trait_id) = get_trait_def_id(cx, &path) {
153 trait_ids.push(trait_id);
159 // Get the actually implemented trait
160 let parent_fn = cx.tcx.hir.get_parent(expr.id);
161 let parent_impl = cx.tcx.hir.get_parent(parent_fn);
164 if parent_impl != ast::CRATE_NODE_ID;
165 if let hir::map::Node::NodeItem(item) = cx.tcx.hir.get(parent_impl);
166 if let hir::Item_::ItemImpl(_, _, _, _, Some(ref trait_ref), _, _) = item.node;
167 if let Some(idx) = trait_ids.iter().position(|&tid| tid == trait_ref.path.def.def_id());
168 if *binop != expected_ops[idx];
170 return Some(traits[idx])
177 struct BinaryExprVisitor {
178 in_binary_expr: bool,
181 impl<'a, 'tcx: 'a> Visitor<'tcx> for BinaryExprVisitor {
182 fn visit_expr(&mut self, expr: &'tcx hir::Expr) {
183 if let hir::ExprBinary(_, _, _) = expr.node {
184 self.in_binary_expr = true;
187 walk_expr(self, expr);
189 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
190 NestedVisitorMap::None