2 use rustc::hir::intravisit;
5 use rustc::{declare_lint, lint_array};
7 use rustc::hir::def::Def;
8 use std::collections::HashSet;
10 use rustc_target::spec::abi::Abi;
11 use syntax::codemap::Span;
12 use crate::utils::{iter_input_pats, span_lint, type_is_unsafe_function};
14 /// **What it does:** Checks for functions with too many parameters.
16 /// **Why is this bad?** Functions with lots of parameters are considered bad
17 /// style and reduce readability (“what does the 5th parameter mean?”). Consider
18 /// grouping some parameters into a new type.
20 /// **Known problems:** None.
24 /// fn foo(x: u32, y: u32, name: &str, c: Color, w: f32, h: f32, a: f32, b:
27 declare_clippy_lint! {
28 pub TOO_MANY_ARGUMENTS,
30 "functions with too many arguments"
33 /// **What it does:** Checks for public functions that dereferences raw pointer
34 /// arguments but are not marked unsafe.
36 /// **Why is this bad?** The function should probably be marked `unsafe`, since
37 /// for an arbitrary raw pointer, there is no way of telling for sure if it is
40 /// **Known problems:**
42 /// * It does not check functions recursively so if the pointer is passed to a
43 /// private non-`unsafe` function which does the dereferencing, the lint won't
45 /// * It only checks for arguments whose type are raw pointers, not raw pointers
46 /// got from an argument in some other way (`fn foo(bar: &[*const u8])` or
47 /// `some_argument.get_raw_ptr()`).
51 /// pub fn foo(x: *const u8) { println!("{}", unsafe { *x }); }
53 declare_clippy_lint! {
54 pub NOT_UNSAFE_PTR_ARG_DEREF,
56 "public functions dereferencing raw pointer arguments but not marked `unsafe`"
59 #[derive(Copy, Clone)]
60 pub struct Functions {
65 pub fn new(threshold: u64) -> Self {
72 impl LintPass for Functions {
73 fn get_lints(&self) -> LintArray {
74 lint_array!(TOO_MANY_ARGUMENTS, NOT_UNSAFE_PTR_ARG_DEREF)
78 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Functions {
81 cx: &LateContext<'a, 'tcx>,
82 kind: intravisit::FnKind<'tcx>,
83 decl: &'tcx hir::FnDecl,
84 body: &'tcx hir::Body,
88 use rustc::hir::map::Node::*;
90 let is_impl = if let Some(NodeItem(item)) = cx.tcx.hir.find(cx.tcx.hir.get_parent_node(nodeid)) {
91 matches!(item.node, hir::ItemKind::Impl(_, _, _, _, Some(_), _, _))
96 let unsafety = match kind {
97 hir::intravisit::FnKind::ItemFn(_, _, hir::FnHeader { unsafety, .. }, _, _) => unsafety,
98 hir::intravisit::FnKind::Method(_, sig, _, _) => sig.header.unsafety,
99 hir::intravisit::FnKind::Closure(_) => return,
102 // don't warn for implementations, it's not their fault
104 // don't lint extern functions decls, it's not their fault either
106 hir::intravisit::FnKind::Method(_, &hir::MethodSig { header: hir::FnHeader { abi: Abi::Rust, .. }, .. }, _, _) |
107 hir::intravisit::FnKind::ItemFn(_, _, hir::FnHeader { abi: Abi::Rust, .. }, _, _) => self.check_arg_number(cx, decl, span),
112 self.check_raw_ptr(cx, unsafety, decl, body, nodeid);
115 fn check_trait_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx hir::TraitItem) {
116 if let hir::TraitItemKind::Method(ref sig, ref eid) = item.node {
117 // don't lint extern functions decls, it's not their fault
118 if sig.header.abi == Abi::Rust {
119 self.check_arg_number(cx, &sig.decl, item.span);
122 if let hir::TraitMethod::Provided(eid) = *eid {
123 let body = cx.tcx.hir.body(eid);
124 self.check_raw_ptr(cx, sig.header.unsafety, &sig.decl, body, item.id);
130 impl<'a, 'tcx> Functions {
131 fn check_arg_number(self, cx: &LateContext, decl: &hir::FnDecl, span: Span) {
132 let args = decl.inputs.len() as u64;
133 if args > self.threshold {
138 &format!("this function has too many arguments ({}/{})", args, self.threshold),
145 cx: &LateContext<'a, 'tcx>,
146 unsafety: hir::Unsafety,
147 decl: &'tcx hir::FnDecl,
148 body: &'tcx hir::Body,
151 let expr = &body.value;
152 if unsafety == hir::Unsafety::Normal && cx.access_levels.is_exported(nodeid) {
153 let raw_ptrs = iter_input_pats(decl, body)
154 .zip(decl.inputs.iter())
155 .filter_map(|(arg, ty)| raw_ptr_arg(arg, ty))
156 .collect::<HashSet<_>>();
158 if !raw_ptrs.is_empty() {
159 let tables = cx.tcx.body_tables(body.id());
160 let mut v = DerefVisitor {
166 hir::intravisit::walk_expr(&mut v, expr);
172 fn raw_ptr_arg(arg: &hir::Arg, ty: &hir::Ty) -> Option<ast::NodeId> {
173 if let (&hir::PatKind::Binding(_, id, _, _), &hir::TyKind::Ptr(_)) = (&arg.pat.node, &ty.node) {
180 struct DerefVisitor<'a, 'tcx: 'a> {
181 cx: &'a LateContext<'a, 'tcx>,
182 ptrs: HashSet<ast::NodeId>,
183 tables: &'a ty::TypeckTables<'tcx>,
186 impl<'a, 'tcx> hir::intravisit::Visitor<'tcx> for DerefVisitor<'a, 'tcx> {
187 fn visit_expr(&mut self, expr: &'tcx hir::Expr) {
189 hir::ExprKind::Call(ref f, ref args) => {
190 let ty = self.tables.expr_ty(f);
192 if type_is_unsafe_function(self.cx, ty) {
198 hir::ExprKind::MethodCall(_, _, ref args) => {
199 let def_id = self.tables.type_dependent_defs()[expr.hir_id].def_id();
200 let base_type = self.cx.tcx.type_of(def_id);
202 if type_is_unsafe_function(self.cx, base_type) {
208 hir::ExprKind::Unary(hir::UnDeref, ref ptr) => self.check_arg(ptr),
212 hir::intravisit::walk_expr(self, expr);
214 fn nested_visit_map<'this>(&'this mut self) -> intravisit::NestedVisitorMap<'this, 'tcx> {
215 intravisit::NestedVisitorMap::None
219 impl<'a, 'tcx: 'a> DerefVisitor<'a, 'tcx> {
220 fn check_arg(&self, ptr: &hir::Expr) {
221 if let hir::ExprKind::Path(ref qpath) = ptr.node {
222 if let Def::Local(id) = self.cx.tables.qpath_def(qpath, ptr.hir_id) {
223 if self.ptrs.contains(&id) {
226 NOT_UNSAFE_PTR_ARG_DEREF,
228 "this public function dereferences a raw pointer but is not marked `unsafe`",