1 use if_chain::if_chain;
3 use rustc::hir::def::{CtorKind, DefKind, Res};
4 use rustc::hir::intravisit::{walk_item, walk_path, walk_ty, NestedVisitorMap, Visitor};
6 use rustc::lint::{in_external_macro, LateContext, LateLintPass, LintArray, LintContext, LintPass};
8 use rustc::ty::{DefIdTree, Ty};
9 use rustc::{declare_lint_pass, declare_tool_lint};
10 use rustc_errors::Applicability;
11 use syntax_pos::symbol::kw;
13 use crate::utils::span_lint_and_sugg;
15 declare_clippy_lint! {
16 /// **What it does:** Checks for unnecessary repetition of structure name when a
17 /// replacement with `Self` is applicable.
19 /// **Why is this bad?** Unnecessary repetition. Mixed use of `Self` and struct
21 /// feels inconsistent.
23 /// **Known problems:**
24 /// - False positive when using associated types (#2843)
25 /// - False positives in some situations when using generics (#3410)
40 /// fn new() -> Self {
47 "Unnecessary structure name repetition whereas `Self` is applicable"
50 declare_lint_pass!(UseSelf => [USE_SELF]);
52 const SEGMENTS_MSG: &str = "segments should be composed of at least 1 element";
54 fn span_use_self_lint(cx: &LateContext<'_, '_>, path: &Path) {
55 // Path segments only include actual path, no methods or fields.
56 let last_path_span = path.segments.last().expect(SEGMENTS_MSG).ident.span;
57 // Only take path up to the end of last_path_span.
58 let span = path.span.with_hi(last_path_span.hi());
64 "unnecessary structure name repetition",
65 "use the applicable keyword",
67 Applicability::MachineApplicable,
71 struct TraitImplTyVisitor<'a, 'tcx: 'a> {
73 cx: &'a LateContext<'a, 'tcx>,
74 trait_type_walker: ty::walk::TypeWalker<'tcx>,
75 impl_type_walker: ty::walk::TypeWalker<'tcx>,
78 impl<'a, 'tcx> Visitor<'tcx> for TraitImplTyVisitor<'a, 'tcx> {
79 fn visit_ty(&mut self, t: &'tcx hir::Ty) {
80 let trait_ty = self.trait_type_walker.next();
81 let impl_ty = self.impl_type_walker.next();
83 if let TyKind::Path(QPath::Resolved(_, path)) = &t.node {
84 // The implementation and trait types don't match which means that
85 // the concrete type was specified by the implementation
86 if impl_ty != trait_ty {
87 if let Some(impl_ty) = impl_ty {
88 if self.item_type == impl_ty {
89 let is_self_ty = if let def::Res::SelfTy(..) = path.res {
96 span_use_self_lint(self.cx, path);
106 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
107 NestedVisitorMap::None
111 fn check_trait_method_impl_decl<'a, 'tcx: 'a>(
112 cx: &'a LateContext<'a, 'tcx>,
114 impl_item: &ImplItem,
115 impl_decl: &'tcx FnDecl,
116 impl_trait_ref: &ty::TraitRef<'_>,
118 let trait_method = cx
120 .associated_items(impl_trait_ref.def_id)
122 assoc_item.kind == ty::AssocKind::Method
125 .hygienic_eq(impl_item.ident, assoc_item.ident, impl_trait_ref.def_id)
127 .expect("impl method matches a trait method");
129 let trait_method_sig = cx.tcx.fn_sig(trait_method.def_id);
130 let trait_method_sig = cx.tcx.erase_late_bound_regions(&trait_method_sig);
132 let impl_method_def_id = cx.tcx.hir().local_def_id_from_hir_id(impl_item.hir_id);
133 let impl_method_sig = cx.tcx.fn_sig(impl_method_def_id);
134 let impl_method_sig = cx.tcx.erase_late_bound_regions(&impl_method_sig);
136 let output_ty = if let FunctionRetTy::Return(ty) = &impl_decl.output {
142 // `impl_decl_ty` (of type `hir::Ty`) represents the type declared in the signature.
143 // `impl_ty` (of type `ty:TyS`) is the concrete type that the compiler has determined for
144 // that declaration. We use `impl_decl_ty` to see if the type was declared as `Self`
145 // and use `impl_ty` to check its concrete type.
146 for (impl_decl_ty, (impl_ty, trait_ty)) in impl_decl.inputs.iter().chain(output_ty).zip(
150 .zip(trait_method_sig.inputs_and_output),
152 let mut visitor = TraitImplTyVisitor {
155 trait_type_walker: trait_ty.walk(),
156 impl_type_walker: impl_ty.walk(),
159 visitor.visit_ty(&impl_decl_ty);
163 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UseSelf {
164 fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx Item) {
165 if in_external_macro(cx.sess(), item.span) {
169 if let ItemKind::Impl(.., ref item_type, ref refs) = item.node;
170 if let TyKind::Path(QPath::Resolved(_, ref item_path)) = item_type.node;
172 let parameters = &item_path.segments.last().expect(SEGMENTS_MSG).args;
173 let should_check = if let Some(ref params) = *parameters {
174 !params.parenthesized && !params.args.iter().any(|arg| match arg {
175 GenericArg::Lifetime(_) => true,
183 let visitor = &mut UseSelfVisitor {
187 let impl_def_id = cx.tcx.hir().local_def_id_from_hir_id(item.hir_id);
188 let impl_trait_ref = cx.tcx.impl_trait_ref(impl_def_id);
190 if let Some(impl_trait_ref) = impl_trait_ref {
191 for impl_item_ref in refs {
192 let impl_item = cx.tcx.hir().impl_item(impl_item_ref.id);
193 if let ImplItemKind::Method(MethodSig{ decl: impl_decl, .. }, impl_body_id)
195 let item_type = cx.tcx.type_of(impl_def_id);
196 check_trait_method_impl_decl(cx, item_type, impl_item, impl_decl, &impl_trait_ref);
198 let body = cx.tcx.hir().body(*impl_body_id);
199 visitor.visit_body(body);
201 visitor.visit_impl_item(impl_item);
205 for impl_item_ref in refs {
206 let impl_item = cx.tcx.hir().impl_item(impl_item_ref.id);
207 visitor.visit_impl_item(impl_item);
216 struct UseSelfVisitor<'a, 'tcx: 'a> {
218 cx: &'a LateContext<'a, 'tcx>,
221 impl<'a, 'tcx> Visitor<'tcx> for UseSelfVisitor<'a, 'tcx> {
222 fn visit_path(&mut self, path: &'tcx Path, _id: HirId) {
223 if path.segments.last().expect(SEGMENTS_MSG).ident.name != kw::SelfUpper {
224 if self.item_path.res == path.res {
225 span_use_self_lint(self.cx, path);
226 } else if let Res::Def(DefKind::Ctor(def::CtorOf::Struct, CtorKind::Fn), ctor_did) = path.res {
227 if self.item_path.res.opt_def_id() == self.cx.tcx.parent(ctor_did) {
228 span_use_self_lint(self.cx, path);
232 walk_path(self, path);
235 fn visit_item(&mut self, item: &'tcx Item) {
238 | ItemKind::Static(..)
240 | ItemKind::Struct(..)
241 | ItemKind::Union(..)
243 | ItemKind::Fn(..) => {
244 // Don't check statements that shadow `Self` or where `Self` can't be used
246 _ => walk_item(self, item),
250 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
251 NestedVisitorMap::All(&self.cx.tcx.hir())