2 use rustc_hir::def_id::DefId;
3 use rustc_infer::infer::at::ToTrace;
4 use rustc_infer::infer::canonical::{Canonical, QueryResponse};
5 use rustc_infer::infer::{DefiningAnchor, InferCtxt, TyCtxtInferExt};
6 use rustc_infer::traits::TraitEngineExt as _;
7 use rustc_middle::ty::query::Providers;
8 use rustc_middle::ty::subst::{GenericArg, Subst, UserSelfTy, UserSubsts};
9 use rustc_middle::ty::{
10 self, EarlyBinder, FnSig, Lift, PolyFnSig, Ty, TyCtxt, TypeFoldable, Variance,
12 use rustc_middle::ty::{ParamEnv, ParamEnvAnd, Predicate, ToPredicate};
13 use rustc_span::{Span, DUMMY_SP};
14 use rustc_trait_selection::infer::InferCtxtBuilderExt;
15 use rustc_trait_selection::infer::InferCtxtExt;
16 use rustc_trait_selection::traits::query::normalize::AtExt;
17 use rustc_trait_selection::traits::query::type_op::ascribe_user_type::AscribeUserType;
18 use rustc_trait_selection::traits::query::type_op::eq::Eq;
19 use rustc_trait_selection::traits::query::type_op::normalize::Normalize;
20 use rustc_trait_selection::traits::query::type_op::prove_predicate::ProvePredicate;
21 use rustc_trait_selection::traits::query::type_op::subtype::Subtype;
22 use rustc_trait_selection::traits::query::{Fallible, NoSolution};
23 use rustc_trait_selection::traits::{Normalized, Obligation, ObligationCause, TraitEngine};
26 pub(crate) fn provide(p: &mut Providers) {
28 type_op_ascribe_user_type,
30 type_op_prove_predicate,
33 type_op_normalize_predicate,
34 type_op_normalize_fn_sig,
35 type_op_normalize_poly_fn_sig,
40 fn type_op_ascribe_user_type<'tcx>(
42 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, AscribeUserType<'tcx>>>,
43 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, ()>>, NoSolution> {
44 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, |infcx, fulfill_cx, key| {
45 type_op_ascribe_user_type_with_span(infcx, fulfill_cx, key, None)
49 /// The core of the `type_op_ascribe_user_type` query: for diagnostics purposes in NLL HRTB errors,
50 /// this query can be re-run to better track the span of the obligation cause, and improve the error
51 /// message. Do not call directly unless you're in that very specific context.
52 pub fn type_op_ascribe_user_type_with_span<'a, 'tcx: 'a>(
53 infcx: &'a InferCtxt<'a, 'tcx>,
54 fulfill_cx: &'a mut dyn TraitEngine<'tcx>,
55 key: ParamEnvAnd<'tcx, AscribeUserType<'tcx>>,
57 ) -> Result<(), NoSolution> {
58 let (param_env, AscribeUserType { mir_ty, def_id, user_substs }) = key.into_parts();
60 "type_op_ascribe_user_type: mir_ty={:?} def_id={:?} user_substs={:?}",
61 mir_ty, def_id, user_substs
64 let mut cx = AscribeUserTypeCx { infcx, param_env, fulfill_cx };
65 cx.relate_mir_and_user_ty(mir_ty, def_id, user_substs, span)?;
69 struct AscribeUserTypeCx<'me, 'tcx> {
70 infcx: &'me InferCtxt<'me, 'tcx>,
71 param_env: ParamEnv<'tcx>,
72 fulfill_cx: &'me mut dyn TraitEngine<'tcx>,
75 impl<'me, 'tcx> AscribeUserTypeCx<'me, 'tcx> {
76 fn normalize<T>(&mut self, value: T) -> T
78 T: TypeFoldable<'tcx>,
81 .partially_normalize_associated_types_in(
82 ObligationCause::misc(DUMMY_SP, hir::CRATE_HIR_ID),
86 .into_value_registering_obligations(self.infcx, self.fulfill_cx)
89 fn relate<T>(&mut self, a: T, variance: Variance, b: T) -> Result<(), NoSolution>
94 .at(&ObligationCause::dummy(), self.param_env)
95 .relate(a, variance, b)?
96 .into_value_registering_obligations(self.infcx, self.fulfill_cx);
100 fn prove_predicate(&mut self, predicate: Predicate<'tcx>, span: Option<Span>) {
101 let cause = if let Some(span) = span {
102 ObligationCause::dummy_with_span(span)
104 ObligationCause::dummy()
106 self.fulfill_cx.register_predicate_obligation(
108 Obligation::new(cause, self.param_env, predicate),
112 fn tcx(&self) -> TyCtxt<'tcx> {
116 fn subst<T>(&self, value: T, substs: &[GenericArg<'tcx>]) -> T
118 T: TypeFoldable<'tcx>,
120 EarlyBinder(value).subst(self.tcx(), substs)
123 #[instrument(level = "debug", skip(self))]
124 fn relate_mir_and_user_ty(
128 user_substs: UserSubsts<'tcx>,
130 ) -> Result<(), NoSolution> {
131 let UserSubsts { user_self_ty, substs } = user_substs;
132 let tcx = self.tcx();
134 let ty = tcx.type_of(def_id);
135 let ty = self.subst(ty, substs);
136 let ty = self.normalize(ty);
137 debug!("relate_type_and_user_type: ty of def-id is {:?}", ty);
139 self.relate(mir_ty, Variance::Invariant, ty)?;
141 // Prove the predicates coming along with `def_id`.
143 // Also, normalize the `instantiated_predicates`
144 // because otherwise we wind up with duplicate "type
145 // outlives" error messages.
146 let instantiated_predicates =
147 self.tcx().predicates_of(def_id).instantiate(self.tcx(), substs);
148 debug!(?instantiated_predicates);
149 for instantiated_predicate in instantiated_predicates.predicates {
150 let instantiated_predicate = self.normalize(instantiated_predicate);
151 self.prove_predicate(instantiated_predicate, span);
154 if let Some(UserSelfTy { impl_def_id, self_ty }) = user_self_ty {
155 let impl_self_ty = self.tcx().type_of(impl_def_id);
156 let impl_self_ty = self.subst(impl_self_ty, &substs);
157 let impl_self_ty = self.normalize(impl_self_ty);
159 self.relate(self_ty, Variance::Invariant, impl_self_ty)?;
161 self.prove_predicate(
162 ty::Binder::dummy(ty::PredicateKind::WellFormed(impl_self_ty.into()))
163 .to_predicate(self.tcx()),
168 // In addition to proving the predicates, we have to
169 // prove that `ty` is well-formed -- this is because
170 // the WF of `ty` is predicated on the substs being
171 // well-formed, and we haven't proven *that*. We don't
172 // want to prove the WF of types from `substs` directly because they
173 // haven't been normalized.
175 // FIXME(nmatsakis): Well, perhaps we should normalize
176 // them? This would only be relevant if some input
177 // type were ill-formed but did not appear in `ty`,
178 // which...could happen with normalization...
179 self.prove_predicate(
180 ty::Binder::dummy(ty::PredicateKind::WellFormed(ty.into())).to_predicate(self.tcx()),
189 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Eq<'tcx>>>,
190 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, ()>>, NoSolution> {
191 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, |infcx, fulfill_cx, key| {
192 let (param_env, Eq { a, b }) = key.into_parts();
194 .at(&ObligationCause::dummy(), param_env)
196 .into_value_registering_obligations(infcx, fulfill_cx);
201 fn type_op_normalize<'tcx, T>(
202 infcx: &InferCtxt<'_, 'tcx>,
203 fulfill_cx: &mut dyn TraitEngine<'tcx>,
204 key: ParamEnvAnd<'tcx, Normalize<T>>,
207 T: fmt::Debug + TypeFoldable<'tcx> + Lift<'tcx>,
209 let (param_env, Normalize { value }) = key.into_parts();
210 let Normalized { value, obligations } =
211 infcx.at(&ObligationCause::dummy(), param_env).normalize(value)?;
212 fulfill_cx.register_predicate_obligations(infcx, obligations);
216 fn type_op_normalize_ty<'tcx>(
218 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<Ty<'tcx>>>>,
219 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, Ty<'tcx>>>, NoSolution> {
220 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, type_op_normalize)
223 fn type_op_normalize_predicate<'tcx>(
225 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<Predicate<'tcx>>>>,
226 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, Predicate<'tcx>>>, NoSolution> {
227 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, type_op_normalize)
230 fn type_op_normalize_fn_sig<'tcx>(
232 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<FnSig<'tcx>>>>,
233 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, FnSig<'tcx>>>, NoSolution> {
234 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, type_op_normalize)
237 fn type_op_normalize_poly_fn_sig<'tcx>(
239 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<PolyFnSig<'tcx>>>>,
240 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, PolyFnSig<'tcx>>>, NoSolution> {
241 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, type_op_normalize)
244 fn type_op_subtype<'tcx>(
246 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Subtype<'tcx>>>,
247 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, ()>>, NoSolution> {
248 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, |infcx, fulfill_cx, key| {
249 let (param_env, Subtype { sub, sup }) = key.into_parts();
251 .at(&ObligationCause::dummy(), param_env)
253 .into_value_registering_obligations(infcx, fulfill_cx);
258 fn type_op_prove_predicate<'tcx>(
260 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, ProvePredicate<'tcx>>>,
261 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, ()>>, NoSolution> {
262 // HACK This bubble is required for this test to pass:
263 // impl-trait/issue-99642.rs
264 tcx.infer_ctxt().with_opaque_type_inference(DefiningAnchor::Bubble).enter_canonical_trait_query(
266 |infcx, fulfill_cx, key| {
267 type_op_prove_predicate_with_cause(infcx, fulfill_cx, key, ObligationCause::dummy());
273 /// The core of the `type_op_prove_predicate` query: for diagnostics purposes in NLL HRTB errors,
274 /// this query can be re-run to better track the span of the obligation cause, and improve the error
275 /// message. Do not call directly unless you're in that very specific context.
276 pub fn type_op_prove_predicate_with_cause<'a, 'tcx: 'a>(
277 infcx: &'a InferCtxt<'a, 'tcx>,
278 fulfill_cx: &'a mut dyn TraitEngine<'tcx>,
279 key: ParamEnvAnd<'tcx, ProvePredicate<'tcx>>,
280 cause: ObligationCause<'tcx>,
282 let (param_env, ProvePredicate { predicate }) = key.into_parts();
283 fulfill_cx.register_predicate_obligation(infcx, Obligation::new(cause, param_env, predicate));