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::{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 type_op_ascribe_user_type_with_span(infcx, fulfill_cx, key, None)
47 /// The core of the `type_op_ascribe_user_type` query: for diagnostics purposes in NLL HRTB errors,
48 /// this query can be re-run to better track the span of the obligation cause, and improve the error
49 /// message. Do not call directly unless you're in that very specific context.
50 pub fn type_op_ascribe_user_type_with_span<'a, 'tcx: 'a>(
51 infcx: &'a InferCtxt<'a, 'tcx>,
52 fulfill_cx: &'a mut dyn TraitEngine<'tcx>,
53 key: ParamEnvAnd<'tcx, AscribeUserType<'tcx>>,
55 ) -> Result<(), NoSolution> {
56 let (param_env, AscribeUserType { mir_ty, def_id, user_substs }) = key.into_parts();
58 "type_op_ascribe_user_type: mir_ty={:?} def_id={:?} user_substs={:?}",
59 mir_ty, def_id, user_substs
62 let mut cx = AscribeUserTypeCx { infcx, param_env, fulfill_cx };
63 cx.relate_mir_and_user_ty(mir_ty, def_id, user_substs, span)?;
67 struct AscribeUserTypeCx<'me, 'tcx> {
68 infcx: &'me InferCtxt<'me, 'tcx>,
69 param_env: ParamEnv<'tcx>,
70 fulfill_cx: &'me mut dyn TraitEngine<'tcx>,
73 impl<'me, 'tcx> AscribeUserTypeCx<'me, 'tcx> {
74 fn normalize<T>(&mut self, value: T) -> T
76 T: TypeFoldable<'tcx>,
79 .partially_normalize_associated_types_in(
80 ObligationCause::misc(DUMMY_SP, hir::CRATE_HIR_ID),
84 .into_value_registering_obligations(self.infcx, self.fulfill_cx)
87 fn relate<T>(&mut self, a: T, variance: Variance, b: T) -> Result<(), NoSolution>
92 .at(&ObligationCause::dummy(), self.param_env)
93 .relate(a, variance, b)?
94 .into_value_registering_obligations(self.infcx, self.fulfill_cx);
98 fn prove_predicate(&mut self, predicate: Predicate<'tcx>, span: Option<Span>) {
99 let cause = if let Some(span) = span {
100 ObligationCause::dummy_with_span(span)
102 ObligationCause::dummy()
104 self.fulfill_cx.register_predicate_obligation(
106 Obligation::new(cause, self.param_env, predicate),
110 fn tcx(&self) -> TyCtxt<'tcx> {
114 fn subst<T>(&self, value: T, substs: &[GenericArg<'tcx>]) -> T
116 T: TypeFoldable<'tcx>,
118 value.subst(self.tcx(), substs)
121 fn relate_mir_and_user_ty(
125 user_substs: UserSubsts<'tcx>,
127 ) -> Result<(), NoSolution> {
128 let UserSubsts { user_self_ty, substs } = user_substs;
129 let tcx = self.tcx();
131 let ty = tcx.type_of(def_id);
132 let ty = self.subst(ty, substs);
133 debug!("relate_type_and_user_type: ty of def-id is {:?}", ty);
134 let ty = self.normalize(ty);
136 self.relate(mir_ty, Variance::Invariant, ty)?;
138 // Prove the predicates coming along with `def_id`.
140 // Also, normalize the `instantiated_predicates`
141 // because otherwise we wind up with duplicate "type
142 // outlives" error messages.
143 let instantiated_predicates =
144 self.tcx().predicates_of(def_id).instantiate(self.tcx(), substs);
145 debug!(?instantiated_predicates.predicates);
146 for instantiated_predicate in instantiated_predicates.predicates {
147 let instantiated_predicate = self.normalize(instantiated_predicate);
148 self.prove_predicate(instantiated_predicate, span);
151 if let Some(UserSelfTy { impl_def_id, self_ty }) = user_self_ty {
152 let impl_self_ty = self.tcx().type_of(impl_def_id);
153 let impl_self_ty = self.subst(impl_self_ty, &substs);
154 let impl_self_ty = self.normalize(impl_self_ty);
156 self.relate(self_ty, Variance::Invariant, impl_self_ty)?;
158 self.prove_predicate(
159 ty::Binder::dummy(ty::PredicateKind::WellFormed(impl_self_ty.into()))
160 .to_predicate(self.tcx()),
165 // In addition to proving the predicates, we have to
166 // prove that `ty` is well-formed -- this is because
167 // the WF of `ty` is predicated on the substs being
168 // well-formed, and we haven't proven *that*. We don't
169 // want to prove the WF of types from `substs` directly because they
170 // haven't been normalized.
172 // FIXME(nmatsakis): Well, perhaps we should normalize
173 // them? This would only be relevant if some input
174 // type were ill-formed but did not appear in `ty`,
175 // which...could happen with normalization...
176 self.prove_predicate(
177 ty::Binder::dummy(ty::PredicateKind::WellFormed(ty.into())).to_predicate(self.tcx()),
186 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Eq<'tcx>>>,
187 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, ()>>, NoSolution> {
188 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, |infcx, fulfill_cx, key| {
189 let (param_env, Eq { a, b }) = key.into_parts();
191 .at(&ObligationCause::dummy(), param_env)
193 .into_value_registering_obligations(infcx, fulfill_cx);
198 fn type_op_normalize<'tcx, T>(
199 infcx: &InferCtxt<'_, 'tcx>,
200 fulfill_cx: &mut dyn TraitEngine<'tcx>,
201 key: ParamEnvAnd<'tcx, Normalize<T>>,
204 T: fmt::Debug + TypeFoldable<'tcx> + Lift<'tcx>,
206 let (param_env, Normalize { value }) = key.into_parts();
207 let Normalized { value, obligations } =
208 infcx.at(&ObligationCause::dummy(), param_env).normalize(value)?;
209 fulfill_cx.register_predicate_obligations(infcx, obligations);
213 fn type_op_normalize_ty<'tcx>(
215 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<Ty<'tcx>>>>,
216 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, Ty<'tcx>>>, NoSolution> {
217 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, type_op_normalize)
220 fn type_op_normalize_predicate<'tcx>(
222 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<Predicate<'tcx>>>>,
223 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, Predicate<'tcx>>>, NoSolution> {
224 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, type_op_normalize)
227 fn type_op_normalize_fn_sig<'tcx>(
229 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<FnSig<'tcx>>>>,
230 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, FnSig<'tcx>>>, NoSolution> {
231 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, type_op_normalize)
234 fn type_op_normalize_poly_fn_sig<'tcx>(
236 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<PolyFnSig<'tcx>>>>,
237 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, PolyFnSig<'tcx>>>, NoSolution> {
238 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, type_op_normalize)
241 fn type_op_subtype<'tcx>(
243 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Subtype<'tcx>>>,
244 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, ()>>, NoSolution> {
245 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, |infcx, fulfill_cx, key| {
246 let (param_env, Subtype { sub, sup }) = key.into_parts();
248 .at(&ObligationCause::dummy(), param_env)
250 .into_value_registering_obligations(infcx, fulfill_cx);
255 fn type_op_prove_predicate<'tcx>(
257 canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, ProvePredicate<'tcx>>>,
258 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, ()>>, NoSolution> {
259 tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, |infcx, fulfill_cx, key| {
260 type_op_prove_predicate_with_cause(infcx, fulfill_cx, key, ObligationCause::dummy());
265 /// The core of the `type_op_prove_predicate` query: for diagnostics purposes in NLL HRTB errors,
266 /// this query can be re-run to better track the span of the obligation cause, and improve the error
267 /// message. Do not call directly unless you're in that very specific context.
268 pub fn type_op_prove_predicate_with_cause<'a, 'tcx: 'a>(
269 infcx: &'a InferCtxt<'a, 'tcx>,
270 fulfill_cx: &'a mut dyn TraitEngine<'tcx>,
271 key: ParamEnvAnd<'tcx, ProvePredicate<'tcx>>,
272 cause: ObligationCause<'tcx>,
274 let (param_env, ProvePredicate { predicate }) = key.into_parts();
275 fulfill_cx.register_predicate_obligation(infcx, Obligation::new(cause, param_env, predicate));