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Commit | Line | Data |
---|---|---|
5e7ed085 | 1 | use rustc_errors::ErrorGuaranteed; |
49aad941 | 2 | use rustc_hir::def_id::DefId; |
ba9703b0 | 3 | use rustc_infer::infer::TyCtxtInferExt; |
49aad941 | 4 | use rustc_middle::query::Providers; |
04454e1e | 5 | use rustc_middle::traits::CodegenObligationError; |
ba9703b0 | 6 | use rustc_middle::ty::subst::SubstsRef; |
9ffffee4 | 7 | use rustc_middle::ty::{self, Instance, TyCtxt, TypeVisitableExt}; |
2b03887a | 8 | use rustc_span::sym; |
ba9703b0 XL |
9 | use rustc_trait_selection::traits; |
10 | use traits::{translate_substs, Reveal}; | |
74b04a01 | 11 | |
353b0b11 FG |
12 | use crate::errors::UnexpectedFnPtrAssociatedItem; |
13 | ||
f9f354fc | 14 | fn resolve_instance<'tcx>( |
74b04a01 | 15 | tcx: TyCtxt<'tcx>, |
f9f354fc | 16 | key: ty::ParamEnvAnd<'tcx, (DefId, SubstsRef<'tcx>)>, |
5e7ed085 | 17 | ) -> Result<Option<Instance<'tcx>>, ErrorGuaranteed> { |
3dfed10e XL |
18 | let (param_env, (def, substs)) = key.into_parts(); |
19 | ||
49aad941 | 20 | let result = if let Some(trait_def_id) = tcx.trait_of_item(def) { |
74b04a01 | 21 | debug!(" => associated item, attempting to find impl in param_env {:#?}", param_env); |
9c376795 FG |
22 | resolve_associated_item( |
23 | tcx, | |
49aad941 | 24 | def, |
9c376795 FG |
25 | param_env, |
26 | trait_def_id, | |
27 | tcx.normalize_erasing_regions(param_env, substs), | |
28 | ) | |
74b04a01 | 29 | } else { |
49aad941 FG |
30 | let ty = tcx.type_of(def); |
31 | let item_type = tcx.subst_and_normalize_erasing_regions(substs, param_env, ty); | |
74b04a01 | 32 | |
1b1a35ee | 33 | let def = match *item_type.kind() { |
923072b8 | 34 | ty::FnDef(def_id, ..) if tcx.is_intrinsic(def_id) => { |
74b04a01 | 35 | debug!(" => intrinsic"); |
49aad941 | 36 | ty::InstanceDef::Intrinsic(def) |
74b04a01 | 37 | } |
ba9703b0 XL |
38 | ty::FnDef(def_id, substs) if Some(def_id) == tcx.lang_items().drop_in_place_fn() => { |
39 | let ty = substs.type_at(0); | |
40 | ||
41 | if ty.needs_drop(tcx, param_env) { | |
3dfed10e | 42 | debug!(" => nontrivial drop glue"); |
1b1a35ee | 43 | match *ty.kind() { |
3dfed10e XL |
44 | ty::Closure(..) |
45 | | ty::Generator(..) | |
46 | | ty::Tuple(..) | |
47 | | ty::Adt(..) | |
48 | | ty::Dynamic(..) | |
49 | | ty::Array(..) | |
50 | | ty::Slice(..) => {} | |
51 | // Drop shims can only be built from ADTs. | |
52 | _ => return Ok(None), | |
74b04a01 | 53 | } |
ba9703b0 | 54 | |
ba9703b0 | 55 | ty::InstanceDef::DropGlue(def_id, Some(ty)) |
74b04a01 | 56 | } else { |
ba9703b0 XL |
57 | debug!(" => trivial drop glue"); |
58 | ty::InstanceDef::DropGlue(def_id, None) | |
74b04a01 XL |
59 | } |
60 | } | |
ba9703b0 XL |
61 | _ => { |
62 | debug!(" => free item"); | |
3dfed10e | 63 | ty::InstanceDef::Item(def) |
ba9703b0 | 64 | } |
74b04a01 | 65 | }; |
f9f354fc | 66 | Ok(Some(Instance { def, substs })) |
74b04a01 | 67 | }; |
6a06907d | 68 | debug!("inner_resolve_instance: result={:?}", result); |
74b04a01 XL |
69 | result |
70 | } | |
71 | ||
72 | fn resolve_associated_item<'tcx>( | |
73 | tcx: TyCtxt<'tcx>, | |
5099ac24 | 74 | trait_item_id: DefId, |
74b04a01 XL |
75 | param_env: ty::ParamEnv<'tcx>, |
76 | trait_id: DefId, | |
77 | rcvr_substs: SubstsRef<'tcx>, | |
5e7ed085 | 78 | ) -> Result<Option<Instance<'tcx>>, ErrorGuaranteed> { |
5099ac24 | 79 | debug!(?trait_item_id, ?param_env, ?trait_id, ?rcvr_substs, "resolve_associated_item"); |
74b04a01 XL |
80 | |
81 | let trait_ref = ty::TraitRef::from_method(tcx, trait_id, rcvr_substs); | |
136023e0 | 82 | |
f2b60f7d | 83 | let vtbl = match tcx.codegen_select_candidate((param_env, ty::Binder::dummy(trait_ref))) { |
04454e1e FG |
84 | Ok(vtbl) => vtbl, |
85 | Err(CodegenObligationError::Ambiguity) => { | |
86 | let reported = tcx.sess.delay_span_bug( | |
87 | tcx.def_span(trait_item_id), | |
49aad941 | 88 | format!( |
f2b60f7d | 89 | "encountered ambiguity selecting `{trait_ref:?}` during codegen, presuming due to \ |
04454e1e | 90 | overflow or prior type error", |
04454e1e FG |
91 | ), |
92 | ); | |
93 | return Err(reported); | |
94 | } | |
95 | Err(CodegenObligationError::Unimplemented) => return Ok(None), | |
96 | Err(CodegenObligationError::FulfillmentError) => return Ok(None), | |
97 | }; | |
74b04a01 XL |
98 | |
99 | // Now that we know which impl is being used, we can dispatch to | |
100 | // the actual function: | |
f9f354fc | 101 | Ok(match vtbl { |
1b1a35ee | 102 | traits::ImplSource::UserDefined(impl_data) => { |
ba9703b0 | 103 | debug!( |
1b1a35ee | 104 | "resolving ImplSource::UserDefined: {:?}, {:?}, {:?}, {:?}", |
5099ac24 | 105 | param_env, trait_item_id, rcvr_substs, impl_data |
ba9703b0 | 106 | ); |
49aad941 FG |
107 | assert!(!rcvr_substs.has_infer()); |
108 | assert!(!trait_ref.has_infer()); | |
74b04a01 | 109 | |
ba9703b0 XL |
110 | let trait_def_id = tcx.trait_id_of_impl(impl_data.impl_def_id).unwrap(); |
111 | let trait_def = tcx.trait_def(trait_def_id); | |
112 | let leaf_def = trait_def | |
f9f354fc | 113 | .ancestors(tcx, impl_data.impl_def_id)? |
5099ac24 | 114 | .leaf_def(tcx, trait_item_id) |
ba9703b0 | 115 | .unwrap_or_else(|| { |
5099ac24 | 116 | bug!("{:?} not found in {:?}", trait_item_id, impl_data.impl_def_id); |
ba9703b0 | 117 | }); |
2b03887a FG |
118 | let infcx = tcx.infer_ctxt().build(); |
119 | let param_env = param_env.with_reveal_all_normalized(tcx); | |
120 | let substs = rcvr_substs.rebase_onto(tcx, trait_def_id, impl_data.substs); | |
121 | let substs = translate_substs( | |
122 | &infcx, | |
123 | param_env, | |
124 | impl_data.impl_def_id, | |
125 | substs, | |
126 | leaf_def.defining_node, | |
127 | ); | |
128 | let substs = infcx.tcx.erase_regions(substs); | |
74b04a01 XL |
129 | |
130 | // Since this is a trait item, we need to see if the item is either a trait default item | |
131 | // or a specialization because we can't resolve those unless we can `Reveal::All`. | |
132 | // NOTE: This should be kept in sync with the similar code in | |
ba9703b0 XL |
133 | // `rustc_trait_selection::traits::project::assemble_candidates_from_impls()`. |
134 | let eligible = if leaf_def.is_final() { | |
135 | // Non-specializable items are always projectable. | |
74b04a01 | 136 | true |
74b04a01 | 137 | } else { |
ba9703b0 XL |
138 | // Only reveal a specializable default if we're past type-checking |
139 | // and the obligation is monomorphic, otherwise passes such as | |
140 | // transmute checking and polymorphic MIR optimizations could | |
141 | // get a result which isn't correct for all monomorphizations. | |
f035d41b | 142 | if param_env.reveal() == Reveal::All { |
ba9703b0 XL |
143 | !trait_ref.still_further_specializable() |
144 | } else { | |
145 | false | |
146 | } | |
74b04a01 XL |
147 | }; |
148 | ||
149 | if !eligible { | |
f9f354fc | 150 | return Ok(None); |
74b04a01 XL |
151 | } |
152 | ||
2b03887a | 153 | // Any final impl is required to define all associated items. |
064997fb | 154 | if !leaf_def.item.defaultness(tcx).has_value() { |
2b03887a FG |
155 | let guard = tcx.sess.delay_span_bug( |
156 | tcx.def_span(leaf_def.item.def_id), | |
157 | "missing value for assoc item in impl", | |
158 | ); | |
159 | return Err(guard); | |
064997fb FG |
160 | } |
161 | ||
fc512014 | 162 | let substs = tcx.erase_regions(substs); |
f9f354fc XL |
163 | |
164 | // Check if we just resolved an associated `const` declaration from | |
165 | // a `trait` to an associated `const` definition in an `impl`, where | |
166 | // the definition in the `impl` has the wrong type (for which an | |
167 | // error has already been/will be emitted elsewhere). | |
5099ac24 FG |
168 | if leaf_def.item.kind == ty::AssocKind::Const |
169 | && trait_item_id != leaf_def.item.def_id | |
2b03887a | 170 | && let Some(leaf_def_item) = leaf_def.item.def_id.as_local() |
f9f354fc | 171 | { |
9c376795 | 172 | tcx.compare_impl_const(( |
2b03887a FG |
173 | leaf_def_item, |
174 | trait_item_id, | |
175 | ))?; | |
f9f354fc XL |
176 | } |
177 | ||
178 | Some(ty::Instance::new(leaf_def.item.def_id, substs)) | |
74b04a01 | 179 | } |
49aad941 FG |
180 | traits::ImplSource::Generator(generator_data) => { |
181 | if cfg!(debug_assertions) && tcx.item_name(trait_item_id) != sym::resume { | |
182 | // For compiler developers who'd like to add new items to `Generator`, | |
183 | // you either need to generate a shim body, or perhaps return | |
184 | // `InstanceDef::Item` pointing to a trait default method body if | |
185 | // it is given a default implementation by the trait. | |
186 | span_bug!( | |
187 | tcx.def_span(generator_data.generator_def_id), | |
188 | "no definition for `{trait_ref}::{}` for built-in generator type", | |
189 | tcx.item_name(trait_item_id) | |
190 | ) | |
191 | } | |
192 | Some(Instance { | |
193 | def: ty::InstanceDef::Item(generator_data.generator_def_id), | |
194 | substs: generator_data.substs, | |
195 | }) | |
196 | } | |
197 | traits::ImplSource::Future(future_data) => { | |
198 | if Some(trait_item_id) == tcx.lang_items().future_poll_fn() { | |
199 | // `Future::poll` is generated by the compiler. | |
200 | Some(Instance { | |
201 | def: ty::InstanceDef::Item(future_data.generator_def_id), | |
202 | substs: future_data.substs, | |
203 | }) | |
204 | } else { | |
205 | // All other methods are default methods of the `Future` trait. | |
206 | // (this assumes that `ImplSource::Future` is only used for methods on `Future`) | |
207 | debug_assert!(tcx.impl_defaultness(trait_item_id).has_value()); | |
208 | Some(Instance::new(trait_item_id, rcvr_substs)) | |
209 | } | |
210 | } | |
1b1a35ee | 211 | traits::ImplSource::Closure(closure_data) => { |
49aad941 FG |
212 | if cfg!(debug_assertions) |
213 | && ![sym::call, sym::call_mut, sym::call_once] | |
214 | .contains(&tcx.item_name(trait_item_id)) | |
215 | { | |
216 | // For compiler developers who'd like to add new items to `Fn`/`FnMut`/`FnOnce`, | |
217 | // you either need to generate a shim body, or perhaps return | |
218 | // `InstanceDef::Item` pointing to a trait default method body if | |
219 | // it is given a default implementation by the trait. | |
220 | span_bug!( | |
221 | tcx.def_span(closure_data.closure_def_id), | |
222 | "no definition for `{trait_ref}::{}` for built-in closure type", | |
223 | tcx.item_name(trait_item_id) | |
224 | ) | |
225 | } | |
487cf647 | 226 | let trait_closure_kind = tcx.fn_trait_kind_from_def_id(trait_id).unwrap(); |
064997fb | 227 | Instance::resolve_closure( |
74b04a01 XL |
228 | tcx, |
229 | closure_data.closure_def_id, | |
230 | closure_data.substs, | |
231 | trait_closure_kind, | |
064997fb | 232 | ) |
74b04a01 | 233 | } |
1b1a35ee | 234 | traits::ImplSource::FnPointer(ref data) => match data.fn_ty.kind() { |
49aad941 FG |
235 | ty::FnDef(..) | ty::FnPtr(..) => { |
236 | if cfg!(debug_assertions) | |
237 | && ![sym::call, sym::call_mut, sym::call_once] | |
238 | .contains(&tcx.item_name(trait_item_id)) | |
239 | { | |
240 | // For compiler developers who'd like to add new items to `Fn`/`FnMut`/`FnOnce`, | |
241 | // you either need to generate a shim body, or perhaps return | |
242 | // `InstanceDef::Item` pointing to a trait default method body if | |
243 | // it is given a default implementation by the trait. | |
244 | bug!( | |
245 | "no definition for `{trait_ref}::{}` for built-in fn type", | |
246 | tcx.item_name(trait_item_id) | |
247 | ) | |
248 | } | |
923072b8 | 249 | Some(Instance { |
49aad941 | 250 | def: ty::InstanceDef::FnPtrShim(trait_item_id, data.fn_ty), |
923072b8 FG |
251 | substs: rcvr_substs, |
252 | }) | |
923072b8 | 253 | } |
49aad941 FG |
254 | _ => bug!( |
255 | "no built-in definition for `{trait_ref}::{}` for non-fn type", | |
256 | tcx.item_name(trait_item_id) | |
257 | ), | |
258 | }, | |
259 | traits::ImplSource::Object(ref data) => { | |
260 | traits::get_vtable_index_of_object_method(tcx, data, trait_item_id).map(|index| { | |
261 | Instance { | |
262 | def: ty::InstanceDef::Virtual(trait_item_id, index), | |
263 | substs: rcvr_substs, | |
264 | } | |
265 | }) | |
74b04a01 | 266 | } |
1b1a35ee | 267 | traits::ImplSource::Builtin(..) => { |
353b0b11 FG |
268 | let lang_items = tcx.lang_items(); |
269 | if Some(trait_ref.def_id) == lang_items.clone_trait() { | |
ba9703b0 | 270 | // FIXME(eddyb) use lang items for methods instead of names. |
5099ac24 | 271 | let name = tcx.item_name(trait_item_id); |
ba9703b0 XL |
272 | if name == sym::clone { |
273 | let self_ty = trait_ref.self_ty(); | |
274 | ||
2b03887a | 275 | let is_copy = self_ty.is_copy_modulo_regions(tcx, param_env); |
1b1a35ee | 276 | match self_ty.kind() { |
3dfed10e | 277 | _ if is_copy => (), |
f2b60f7d FG |
278 | ty::Generator(..) |
279 | | ty::GeneratorWitness(..) | |
280 | | ty::Closure(..) | |
281 | | ty::Tuple(..) => {} | |
3dfed10e XL |
282 | _ => return Ok(None), |
283 | }; | |
ba9703b0 XL |
284 | |
285 | Some(Instance { | |
5099ac24 | 286 | def: ty::InstanceDef::CloneShim(trait_item_id, self_ty), |
ba9703b0 XL |
287 | substs: rcvr_substs, |
288 | }) | |
289 | } else { | |
290 | assert_eq!(name, sym::clone_from); | |
291 | ||
292 | // Use the default `fn clone_from` from `trait Clone`. | |
fc512014 | 293 | let substs = tcx.erase_regions(rcvr_substs); |
5099ac24 | 294 | Some(ty::Instance::new(trait_item_id, substs)) |
ba9703b0 | 295 | } |
353b0b11 FG |
296 | } else if Some(trait_ref.def_id) == lang_items.fn_ptr_trait() { |
297 | if lang_items.fn_ptr_addr() == Some(trait_item_id) { | |
298 | let self_ty = trait_ref.self_ty(); | |
299 | if !matches!(self_ty.kind(), ty::FnPtr(..)) { | |
300 | return Ok(None); | |
301 | } | |
302 | Some(Instance { | |
303 | def: ty::InstanceDef::FnPtrAddrShim(trait_item_id, self_ty), | |
304 | substs: rcvr_substs, | |
305 | }) | |
306 | } else { | |
307 | tcx.sess.emit_fatal(UnexpectedFnPtrAssociatedItem { | |
308 | span: tcx.def_span(trait_item_id), | |
309 | }) | |
310 | } | |
74b04a01 XL |
311 | } else { |
312 | None | |
313 | } | |
314 | } | |
1b1a35ee XL |
315 | traits::ImplSource::AutoImpl(..) |
316 | | traits::ImplSource::Param(..) | |
317 | | traits::ImplSource::TraitAlias(..) | |
c295e0f8 | 318 | | traits::ImplSource::TraitUpcasting(_) |
2b03887a | 319 | | traits::ImplSource::ConstDestruct(_) => None, |
f9f354fc | 320 | }) |
74b04a01 | 321 | } |
ba9703b0 | 322 | |
49aad941 FG |
323 | pub fn provide(providers: &mut Providers) { |
324 | *providers = Providers { resolve_instance, ..*providers }; | |
ba9703b0 | 325 | } |