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::{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::{self, FnSig, Lift, PolyFnSig, Ty, TyCtxt, TypeFoldable, Variance};
10 use rustc_middle::ty::{ParamEnv, ParamEnvAnd, Predicate, ToPredicate};
11 use rustc_span::DUMMY_SP;
12 use rustc_trait_selection::infer::InferCtxtBuilderExt;
13 use rustc_trait_selection::infer::InferCtxtExt;
14 use rustc_trait_selection::traits::query::normalize::AtExt;
15 use rustc_trait_selection::traits::query::type_op::ascribe_user_type::AscribeUserType;
16 use rustc_trait_selection::traits::query::type_op::eq::Eq;
17 use rustc_trait_selection::traits::query::type_op::normalize::Normalize;
18 use rustc_trait_selection::traits::query::type_op::prove_predicate::ProvePredicate;
19 use rustc_trait_selection::traits::query::type_op::subtype::Subtype;
20 use rustc_trait_selection::traits::query::{Fallible, NoSolution};
21 use rustc_trait_selection::traits::{Normalized, Obligation, ObligationCause, TraitEngine};
24 crate fn provide(p: &mut Providers<'_>) {
26 type_op_ascribe_user_type,
28 type_op_prove_predicate,
31 type_op_normalize_predicate,
32 type_op_normalize_fn_sig,
33 type_op_normalize_poly_fn_sig,
38 fn type_op_ascribe_user_type<'tcx>(
40 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, AscribeUserType<'tcx>>>,
41 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, ()>>, NoSolution> {
42 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, |infcx, fulfill_cx, key| {
43 let (param_env, AscribeUserType { mir_ty, def_id, user_substs }) = key.into_parts();
46 "type_op_ascribe_user_type: mir_ty={:?} def_id={:?} user_substs={:?}",
47 mir_ty, def_id, user_substs
50 let mut cx = AscribeUserTypeCx { infcx, param_env, fulfill_cx };
51 cx.relate_mir_and_user_ty(mir_ty, def_id, user_substs)?;
57 struct AscribeUserTypeCx<'me, 'tcx> {
58 infcx: &'me InferCtxt<'me, 'tcx>,
59 param_env: ParamEnv<'tcx>,
60 fulfill_cx: &'me mut dyn TraitEngine<'tcx>,
63 impl AscribeUserTypeCx<'me, 'tcx> {
64 fn normalize<T>(&mut self, value: T) -> T
66 T: TypeFoldable<'tcx>,
69 .partially_normalize_associated_types_in(
75 .into_value_registering_obligations(self.infcx, self.fulfill_cx)
78 fn relate<T>(&mut self, a: T, variance: Variance, b: T) -> Result<(), NoSolution>
83 .at(&ObligationCause::dummy(), self.param_env)
84 .relate(a, variance, b)?
85 .into_value_registering_obligations(self.infcx, self.fulfill_cx);
89 fn prove_predicate(&mut self, predicate: Predicate<'tcx>) {
90 self.fulfill_cx.register_predicate_obligation(
92 Obligation::new(ObligationCause::dummy(), self.param_env, predicate),
96 fn tcx(&self) -> TyCtxt<'tcx> {
100 fn subst<T>(&self, value: T, substs: &[GenericArg<'tcx>]) -> T
102 T: TypeFoldable<'tcx>,
104 value.subst(self.tcx(), substs)
107 fn relate_mir_and_user_ty(
111 user_substs: UserSubsts<'tcx>,
112 ) -> Result<(), NoSolution> {
113 let UserSubsts { user_self_ty, substs } = user_substs;
114 let tcx = self.tcx();
116 let ty = tcx.type_of(def_id);
117 let ty = self.subst(ty, substs);
118 debug!("relate_type_and_user_type: ty of def-id is {:?}", ty);
119 let ty = self.normalize(ty);
121 self.relate(mir_ty, Variance::Invariant, ty)?;
123 // Prove the predicates coming along with `def_id`.
125 // Also, normalize the `instantiated_predicates`
126 // because otherwise we wind up with duplicate "type
127 // outlives" error messages.
128 let instantiated_predicates =
129 self.tcx().predicates_of(def_id).instantiate(self.tcx(), substs);
130 for instantiated_predicate in instantiated_predicates.predicates {
131 let instantiated_predicate = self.normalize(instantiated_predicate);
132 self.prove_predicate(instantiated_predicate);
135 if let Some(UserSelfTy { impl_def_id, self_ty }) = user_self_ty {
136 let impl_self_ty = self.tcx().type_of(impl_def_id);
137 let impl_self_ty = self.subst(impl_self_ty, &substs);
138 let impl_self_ty = self.normalize(impl_self_ty);
140 self.relate(self_ty, Variance::Invariant, impl_self_ty)?;
142 self.prove_predicate(
143 ty::PredicateKind::WellFormed(impl_self_ty.into()).to_predicate(self.tcx()),
147 // In addition to proving the predicates, we have to
148 // prove that `ty` is well-formed -- this is because
149 // the WF of `ty` is predicated on the substs being
150 // well-formed, and we haven't proven *that*. We don't
151 // want to prove the WF of types from `substs` directly because they
152 // haven't been normalized.
154 // FIXME(nmatsakis): Well, perhaps we should normalize
155 // them? This would only be relevant if some input
156 // type were ill-formed but did not appear in `ty`,
157 // which...could happen with normalization...
158 self.prove_predicate(ty::PredicateKind::WellFormed(ty.into()).to_predicate(self.tcx()));
165 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Eq<'tcx>>>,
166 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, ()>>, NoSolution> {
167 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, |infcx, fulfill_cx, key| {
168 let (param_env, Eq { a, b }) = key.into_parts();
170 .at(&ObligationCause::dummy(), param_env)
172 .into_value_registering_obligations(infcx, fulfill_cx);
177 fn type_op_normalize<T>(
178 infcx: &InferCtxt<'_, 'tcx>,
179 fulfill_cx: &mut dyn TraitEngine<'tcx>,
180 key: ParamEnvAnd<'tcx, Normalize<T>>,
183 T: fmt::Debug + TypeFoldable<'tcx> + Lift<'tcx>,
185 let (param_env, Normalize { value }) = key.into_parts();
186 let Normalized { value, obligations } =
187 infcx.at(&ObligationCause::dummy(), param_env).normalize(&value)?;
188 fulfill_cx.register_predicate_obligations(infcx, obligations);
192 fn type_op_normalize_ty(
194 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<Ty<'tcx>>>>,
195 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, Ty<'tcx>>>, NoSolution> {
196 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, type_op_normalize)
199 fn type_op_normalize_predicate(
201 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<Predicate<'tcx>>>>,
202 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, Predicate<'tcx>>>, NoSolution> {
203 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, type_op_normalize)
206 fn type_op_normalize_fn_sig(
208 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<FnSig<'tcx>>>>,
209 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, FnSig<'tcx>>>, NoSolution> {
210 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, type_op_normalize)
213 fn type_op_normalize_poly_fn_sig(
215 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<PolyFnSig<'tcx>>>>,
216 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, PolyFnSig<'tcx>>>, NoSolution> {
217 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, type_op_normalize)
220 fn type_op_subtype<'tcx>(
222 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Subtype<'tcx>>>,
223 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, ()>>, NoSolution> {
224 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, |infcx, fulfill_cx, key| {
225 let (param_env, Subtype { sub, sup }) = key.into_parts();
227 .at(&ObligationCause::dummy(), param_env)
229 .into_value_registering_obligations(infcx, fulfill_cx);
234 fn type_op_prove_predicate<'tcx>(
236 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, ProvePredicate<'tcx>>>,
237 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, ()>>, NoSolution> {
238 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, |infcx, fulfill_cx, key| {
239 let (param_env, ProvePredicate { predicate }) = key.into_parts();
240 fulfill_cx.register_predicate_obligation(
242 Obligation::new(ObligationCause::dummy(), param_env, predicate),