1 use crate::utils::{iter_input_pats, span_lint, type_is_unsafe_function};
4 use rustc::hir::def::Def;
5 use rustc::hir::intravisit;
6 use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
8 use rustc::{declare_tool_lint, lint_array};
9 use rustc_data_structures::fx::FxHashSet;
10 use rustc_target::spec::abi::Abi;
12 use syntax::source_map::Span;
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: f32) {
28 declare_clippy_lint! {
29 pub TOO_MANY_ARGUMENTS,
31 "functions with too many arguments"
34 /// **What it does:** Checks for public functions that dereferences raw pointer
35 /// arguments but are not marked unsafe.
37 /// **Why is this bad?** The function should probably be marked `unsafe`, since
38 /// for an arbitrary raw pointer, there is no way of telling for sure if it is
41 /// **Known problems:**
43 /// * It does not check functions recursively so if the pointer is passed to a
44 /// private non-`unsafe` function which does the dereferencing, the lint won't
46 /// * It only checks for arguments whose type are raw pointers, not raw pointers
47 /// got from an argument in some other way (`fn foo(bar: &[*const u8])` or
48 /// `some_argument.get_raw_ptr()`).
52 /// pub fn foo(x: *const u8) {
53 /// println!("{}", unsafe { *x });
56 declare_clippy_lint! {
57 pub NOT_UNSAFE_PTR_ARG_DEREF,
59 "public functions dereferencing raw pointer arguments but not marked `unsafe`"
62 #[derive(Copy, Clone)]
63 pub struct Functions {
68 pub fn new(threshold: u64) -> Self {
73 impl LintPass for Functions {
74 fn get_lints(&self) -> LintArray {
75 lint_array!(TOO_MANY_ARGUMENTS, NOT_UNSAFE_PTR_ARG_DEREF)
79 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Functions {
82 cx: &LateContext<'a, 'tcx>,
83 kind: intravisit::FnKind<'tcx>,
84 decl: &'tcx hir::FnDecl,
85 body: &'tcx hir::Body,
89 let is_impl = if let Some(hir::Node::Item(item)) = cx.tcx.hir().find(cx.tcx.hir().get_parent_node(nodeid)) {
90 matches!(item.node, hir::ItemKind::Impl(_, _, _, _, Some(_), _, _))
95 let unsafety = match kind {
96 hir::intravisit::FnKind::ItemFn(_, _, hir::FnHeader { unsafety, .. }, _, _) => unsafety,
97 hir::intravisit::FnKind::Method(_, sig, _, _) => sig.header.unsafety,
98 hir::intravisit::FnKind::Closure(_) => return,
101 // don't warn for implementations, it's not their fault
103 // don't lint extern functions decls, it's not their fault either
105 hir::intravisit::FnKind::Method(
108 header: hir::FnHeader { abi: Abi::Rust, .. },
114 | hir::intravisit::FnKind::ItemFn(_, _, hir::FnHeader { abi: Abi::Rust, .. }, _, _) => {
115 self.check_arg_number(cx, decl, span)
121 self.check_raw_ptr(cx, unsafety, decl, body, nodeid);
124 fn check_trait_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx hir::TraitItem) {
125 if let hir::TraitItemKind::Method(ref sig, ref eid) = item.node {
126 // don't lint extern functions decls, it's not their fault
127 if sig.header.abi == Abi::Rust {
128 self.check_arg_number(cx, &sig.decl, item.span);
131 if let hir::TraitMethod::Provided(eid) = *eid {
132 let body = cx.tcx.hir().body(eid);
133 self.check_raw_ptr(cx, sig.header.unsafety, &sig.decl, body, item.id);
139 impl<'a, 'tcx> Functions {
140 fn check_arg_number(self, cx: &LateContext<'_, '_>, decl: &hir::FnDecl, span: Span) {
141 let args = decl.inputs.len() as u64;
142 if args > self.threshold {
147 &format!("this function has too many arguments ({}/{})", args, self.threshold),
154 cx: &LateContext<'a, 'tcx>,
155 unsafety: hir::Unsafety,
156 decl: &'tcx hir::FnDecl,
157 body: &'tcx hir::Body,
160 let expr = &body.value;
161 if unsafety == hir::Unsafety::Normal && cx.access_levels.is_exported(nodeid) {
162 let raw_ptrs = iter_input_pats(decl, body)
163 .zip(decl.inputs.iter())
164 .filter_map(|(arg, ty)| raw_ptr_arg(arg, ty))
165 .collect::<FxHashSet<_>>();
167 if !raw_ptrs.is_empty() {
168 let tables = cx.tcx.body_tables(body.id());
169 let mut v = DerefVisitor {
175 hir::intravisit::walk_expr(&mut v, expr);
181 fn raw_ptr_arg(arg: &hir::Arg, ty: &hir::Ty) -> Option<ast::NodeId> {
182 if let (&hir::PatKind::Binding(_, id, _, _), &hir::TyKind::Ptr(_)) = (&arg.pat.node, &ty.node) {
189 struct DerefVisitor<'a, 'tcx: 'a> {
190 cx: &'a LateContext<'a, 'tcx>,
191 ptrs: FxHashSet<ast::NodeId>,
192 tables: &'a ty::TypeckTables<'tcx>,
195 impl<'a, 'tcx> hir::intravisit::Visitor<'tcx> for DerefVisitor<'a, 'tcx> {
196 fn visit_expr(&mut self, expr: &'tcx hir::Expr) {
198 hir::ExprKind::Call(ref f, ref args) => {
199 let ty = self.tables.expr_ty(f);
201 if type_is_unsafe_function(self.cx, ty) {
207 hir::ExprKind::MethodCall(_, _, ref args) => {
208 let def_id = self.tables.type_dependent_defs()[expr.hir_id].def_id();
209 let base_type = self.cx.tcx.type_of(def_id);
211 if type_is_unsafe_function(self.cx, base_type) {
217 hir::ExprKind::Unary(hir::UnDeref, ref ptr) => self.check_arg(ptr),
221 hir::intravisit::walk_expr(self, expr);
223 fn nested_visit_map<'this>(&'this mut self) -> intravisit::NestedVisitorMap<'this, 'tcx> {
224 intravisit::NestedVisitorMap::None
228 impl<'a, 'tcx: 'a> DerefVisitor<'a, 'tcx> {
229 fn check_arg(&self, ptr: &hir::Expr) {
230 if let hir::ExprKind::Path(ref qpath) = ptr.node {
231 if let Def::Local(id) = self.cx.tables.qpath_def(qpath, ptr.hir_id) {
232 if self.ptrs.contains(&id) {
235 NOT_UNSAFE_PTR_ARG_DEREF,
237 "this public function dereferences a raw pointer but is not marked `unsafe`",