1 use clippy_utils::diagnostics::span_lint_and_then;
2 use rustc_data_structures::fx::FxHashMap;
3 use rustc_hir::def::{DefKind, Res};
4 use rustc_hir::{Impl, ItemKind, Node, Path, QPath, TraitRef, TyKind};
5 use rustc_lint::{LateContext, LateLintPass};
6 use rustc_middle::ty::AssocKind;
7 use rustc_session::{declare_lint_pass, declare_tool_lint};
8 use rustc_span::symbol::Symbol;
10 use std::collections::{BTreeMap, BTreeSet};
12 declare_clippy_lint! {
14 /// It lints if a struct has two method with same time:
15 /// one from a trait, another not from trait.
17 /// ### Why is this bad?
38 "two method with same name"
41 declare_lint_pass!(SameNameMethod => [SAME_NAME_METHOD]);
44 impl_methods: BTreeMap<Symbol, Span>,
45 trait_methods: BTreeMap<Symbol, Vec<Span>>,
48 impl<'tcx> LateLintPass<'tcx> for SameNameMethod {
49 fn check_crate_post(&mut self, cx: &LateContext<'tcx>) {
50 let mut map = FxHashMap::<Res, ExistingName>::default();
52 for item in cx.tcx.hir().items() {
53 if let ItemKind::Impl(Impl {
60 if let TyKind::Path(QPath::Resolved(_, Path { res, .. })) = self_ty.kind {
61 if !map.contains_key(res) {
65 impl_methods: BTreeMap::new(),
66 trait_methods: BTreeMap::new(),
70 let existing_name = map.get_mut(res).unwrap();
74 let mut methods_in_trait: BTreeSet<Symbol> = if_chain! {
75 if let Some(Node::TraitRef(TraitRef { path, .. })) =
76 cx.tcx.hir().find(trait_ref.hir_ref_id);
77 if let Res::Def(DefKind::Trait, did) = path.res;
80 // `rustc_middle::ty::assoc::AssocItems::items` is public,
81 // we can iterate its keys instead of `in_definition_order`,
82 // which's more efficient
84 .associated_items(did)
85 .in_definition_order()
86 .filter(|assoc_item| {
87 matches!(assoc_item.kind, AssocKind::Fn)
89 .map(|assoc_item| assoc_item.ident.name)
96 let mut check_trait_method = |method_name: Symbol, trait_method_span: Span| {
97 if let Some(impl_span) = existing_name.impl_methods.get(&method_name) {
102 "method's name is same to an existing method in a trait",
106 &format!("existing `{}` defined here", method_name),
111 if let Some(v) = existing_name.trait_methods.get_mut(&method_name) {
112 v.push(trait_method_span);
114 existing_name.trait_methods.insert(method_name, vec![trait_method_span]);
118 for impl_item_ref in (*items).iter().filter(|impl_item_ref| {
119 matches!(impl_item_ref.kind, rustc_hir::AssocItemKind::Fn { .. })
121 let method_name = impl_item_ref.ident.name;
122 methods_in_trait.remove(&method_name);
123 check_trait_method(method_name, impl_item_ref.span);
126 for method_name in methods_in_trait {
127 check_trait_method(method_name, item.span);
131 for impl_item_ref in (*items).iter().filter(|impl_item_ref| {
132 matches!(impl_item_ref.kind, rustc_hir::AssocItemKind::Fn { .. })
134 let method_name = impl_item_ref.ident.name;
135 let impl_span = impl_item_ref.span;
136 if let Some(trait_spans) = existing_name.trait_methods.get(&method_name) {
141 "method's name is same to an existing method in a trait",
143 // TODO should we `span_note` on every trait?
144 // iterate on trait_spans?
147 &format!("existing `{}` defined here", method_name),
152 existing_name.impl_methods.insert(method_name, impl_span);