1 //! The code in this module gathers up all of the inherent impls in
2 //! the current crate and organizes them in a map. It winds up
3 //! touching the whole crate and thus must be recomputed completely
4 //! for any change, but it is very cheap to compute. In practice, most
5 //! code in the compiler never *directly* requests this map. Instead,
6 //! it requests the inherent impls specific to some type (via
7 //! `tcx.inherent_impls(def_id)`). That value, however,
8 //! is computed by selecting an idea from this table.
10 use rustc::hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
12 use rustc::hir::itemlikevisit::ItemLikeVisitor;
13 use rustc::ty::{self, CrateInherentImpls, TyCtxt};
18 /// On-demand query: yields a map containing all types mapped to their inherent impls.
19 pub fn crate_inherent_impls(
22 ) -> &CrateInherentImpls {
23 assert_eq!(crate_num, LOCAL_CRATE);
25 let krate = tcx.hir().krate();
26 let mut collect = InherentCollect {
28 impls_map: Default::default(),
30 krate.visit_all_item_likes(&mut collect);
31 tcx.arena.alloc(collect.impls_map)
34 /// On-demand query: yields a vector of the inherent impls for a specific type.
35 pub fn inherent_impls(tcx: TyCtxt<'_>, ty_def_id: DefId) -> &[DefId] {
36 assert!(ty_def_id.is_local());
38 let crate_map = tcx.crate_inherent_impls(ty_def_id.krate);
39 match crate_map.inherent_impls.get(&ty_def_id) {
45 struct InherentCollect<'tcx> {
47 impls_map: CrateInherentImpls,
50 impl ItemLikeVisitor<'v> for InherentCollect<'tcx> {
51 fn visit_item(&mut self, item: &hir::Item) {
52 let ty = match item.kind {
53 hir::ItemKind::Impl(.., None, ref ty, _) => ty,
57 let def_id = self.tcx.hir().local_def_id(item.hir_id);
58 let self_ty = self.tcx.type_of(def_id);
59 let lang_items = self.tcx.lang_items();
62 self.check_def_id(item, def.did);
65 self.check_def_id(item, did);
67 ty::Dynamic(ref data, ..) if data.principal_def_id().is_some() => {
68 self.check_def_id(item, data.principal_def_id().unwrap());
71 self.check_primitive_impl(def_id,
72 lang_items.bool_impl(),
79 self.check_primitive_impl(def_id,
80 lang_items.char_impl(),
87 self.check_primitive_impl(def_id,
88 lang_items.str_impl(),
89 lang_items.str_alloc_impl(),
94 ty::Slice(slice_item) if slice_item == self.tcx.types.u8 => {
95 self.check_primitive_impl(def_id,
96 lang_items.slice_u8_impl(),
97 lang_items.slice_u8_alloc_impl(),
103 self.check_primitive_impl(def_id,
104 lang_items.slice_impl(),
105 lang_items.slice_alloc_impl(),
110 ty::RawPtr(ty::TypeAndMut { ty: _, mutbl: hir::MutImmutable }) => {
111 self.check_primitive_impl(def_id,
112 lang_items.const_ptr_impl(),
118 ty::RawPtr(ty::TypeAndMut { ty: _, mutbl: hir::MutMutable }) => {
119 self.check_primitive_impl(def_id,
120 lang_items.mut_ptr_impl(),
126 ty::Int(ast::IntTy::I8) => {
127 self.check_primitive_impl(def_id,
128 lang_items.i8_impl(),
134 ty::Int(ast::IntTy::I16) => {
135 self.check_primitive_impl(def_id,
136 lang_items.i16_impl(),
142 ty::Int(ast::IntTy::I32) => {
143 self.check_primitive_impl(def_id,
144 lang_items.i32_impl(),
150 ty::Int(ast::IntTy::I64) => {
151 self.check_primitive_impl(def_id,
152 lang_items.i64_impl(),
158 ty::Int(ast::IntTy::I128) => {
159 self.check_primitive_impl(def_id,
160 lang_items.i128_impl(),
166 ty::Int(ast::IntTy::Isize) => {
167 self.check_primitive_impl(def_id,
168 lang_items.isize_impl(),
174 ty::Uint(ast::UintTy::U8) => {
175 self.check_primitive_impl(def_id,
176 lang_items.u8_impl(),
182 ty::Uint(ast::UintTy::U16) => {
183 self.check_primitive_impl(def_id,
184 lang_items.u16_impl(),
190 ty::Uint(ast::UintTy::U32) => {
191 self.check_primitive_impl(def_id,
192 lang_items.u32_impl(),
198 ty::Uint(ast::UintTy::U64) => {
199 self.check_primitive_impl(def_id,
200 lang_items.u64_impl(),
206 ty::Uint(ast::UintTy::U128) => {
207 self.check_primitive_impl(def_id,
208 lang_items.u128_impl(),
214 ty::Uint(ast::UintTy::Usize) => {
215 self.check_primitive_impl(def_id,
216 lang_items.usize_impl(),
222 ty::Float(ast::FloatTy::F32) => {
223 self.check_primitive_impl(def_id,
224 lang_items.f32_impl(),
225 lang_items.f32_runtime_impl(),
230 ty::Float(ast::FloatTy::F64) => {
231 self.check_primitive_impl(def_id,
232 lang_items.f64_impl(),
233 lang_items.f64_runtime_impl(),
242 struct_span_err!(self.tcx.sess,
245 "no base type found for inherent implementation")
246 .span_label(ty.span, "impl requires a base type")
247 .note(&format!("either implement a trait on it or create a newtype \
248 to wrap it instead"))
255 fn visit_trait_item(&mut self, _trait_item: &hir::TraitItem) {
258 fn visit_impl_item(&mut self, _impl_item: &hir::ImplItem) {
262 impl InherentCollect<'tcx> {
263 fn check_def_id(&mut self, item: &hir::Item, def_id: DefId) {
264 if def_id.is_local() {
265 // Add the implementation to the mapping from implementation to base
266 // type def ID, if there is a base type for this implementation and
267 // the implementation does not have any associated traits.
268 let impl_def_id = self.tcx.hir().local_def_id(item.hir_id);
269 let vec = self.impls_map.inherent_impls.entry(def_id).or_default();
270 vec.push(impl_def_id);
272 struct_span_err!(self.tcx.sess,
275 "cannot define inherent `impl` for a type outside of the crate \
276 where the type is defined")
277 .span_label(item.span, "impl for type defined outside of crate.")
278 .note("define and implement a trait or new type instead")
283 fn check_primitive_impl(&self,
285 lang_def_id: Option<DefId>,
286 lang_def_id2: Option<DefId>,
290 match (lang_def_id, lang_def_id2) {
291 (Some(lang_def_id), _) if lang_def_id == impl_def_id => {
294 (_, Some(lang_def_id)) if lang_def_id == impl_def_id => {
298 struct_span_err!(self.tcx.sess,
301 "only a single inherent implementation marked with `#[lang = \
302 \"{}\"]` is allowed for the `{}` primitive",
305 .span_help(span, "consider using a trait to implement these methods")