diff options
Diffstat (limited to 'compiler/rustc_trait_selection/src/traits/select/confirmation.rs')
| -rw-r--r-- | compiler/rustc_trait_selection/src/traits/select/confirmation.rs | 55 |
1 files changed, 32 insertions, 23 deletions
diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs index fda415155..82a59831b 100644 --- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs +++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs @@ -2,7 +2,7 @@ //! //! Confirmation unifies the output type parameters of the trait //! with the values found in the obligation, possibly yielding a -//! type error. See the [rustc dev guide] for more details. +//! type error. See the [rustc dev guide] for more details. //! //! [rustc dev guide]: //! https://rustc-dev-guide.rust-lang.org/traits/resolution.html#confirmation @@ -12,9 +12,10 @@ use rustc_index::bit_set::GrowableBitSet; use rustc_infer::infer::InferOk; use rustc_infer::infer::LateBoundRegionConversionTime::HigherRankedType; use rustc_middle::ty::{ - self, GenericArg, GenericArgKind, GenericParamDefKind, InternalSubsts, SubstsRef, - ToPolyTraitRef, ToPredicate, Ty, TyCtxt, + self, Binder, GenericArg, GenericArgKind, GenericParamDefKind, InternalSubsts, SubstsRef, + ToPolyTraitRef, ToPredicate, TraitRef, Ty, TyCtxt, }; +use rustc_session::config::TraitSolver; use rustc_span::def_id::DefId; use crate::traits::project::{normalize_with_depth, normalize_with_depth_to}; @@ -83,7 +84,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { ImplSource::Object(data) } - ClosureCandidate => { + ClosureCandidate { .. } => { let vtable_closure = self.confirm_closure_candidate(obligation)?; ImplSource::Closure(vtable_closure) } @@ -98,8 +99,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { ImplSource::Future(vtable_future) } - FnPointerCandidate { .. } => { - let data = self.confirm_fn_pointer_candidate(obligation)?; + FnPointerCandidate { is_const } => { + let data = self.confirm_fn_pointer_candidate(obligation, is_const)?; ImplSource::FnPointer(data) } @@ -155,13 +156,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let placeholder_self_ty = placeholder_trait_predicate.self_ty(); let placeholder_trait_predicate = ty::Binder::dummy(placeholder_trait_predicate); let (def_id, substs) = match *placeholder_self_ty.kind() { - ty::Projection(proj) => (proj.item_def_id, proj.substs), - ty::Opaque(def_id, substs) => (def_id, substs), + ty::Alias(_, ty::AliasTy { def_id, substs, .. }) => (def_id, substs), _ => bug!("projection candidate for unexpected type: {:?}", placeholder_self_ty), }; - let candidate_predicate = - tcx.bound_item_bounds(def_id).map_bound(|i| i[idx]).subst(tcx, substs); + let candidate_predicate = tcx.item_bounds(def_id).map_bound(|i| i[idx]).subst(tcx, substs); let candidate = candidate_predicate .to_opt_poly_trait_pred() .expect("projection candidate is not a trait predicate") @@ -184,10 +183,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { .map_err(|_| Unimplemented) })?); - if let ty::Projection(..) = placeholder_self_ty.kind() { - let predicates = tcx.predicates_of(def_id).instantiate_own(tcx, substs).predicates; - debug!(?predicates, "projection predicates"); - for predicate in predicates { + if let ty::Alias(ty::Projection, ..) = placeholder_self_ty.kind() { + let predicates = tcx.predicates_of(def_id).instantiate_own(tcx, substs); + for (predicate, _) in predicates { let normalized = normalize_with_depth_to( self, obligation.param_env, @@ -357,8 +355,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { nested, ); - // Adds the predicates from the trait. Note that this contains a `Self: Trait` - // predicate as usual. It won't have any effect since auto traits are coinductive. + // Adds the predicates from the trait. Note that this contains a `Self: Trait` + // predicate as usual. It won't have any effect since auto traits are coinductive. obligations.extend(trait_obligations); debug!(?obligations, "vtable_auto_impl"); @@ -511,7 +509,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { // This maybe belongs in wf, but that can't (doesn't) handle // higher-ranked things. // Prevent, e.g., `dyn Iterator<Item = str>`. - for bound in self.tcx().bound_item_bounds(assoc_type).transpose_iter() { + for bound in self.tcx().item_bounds(assoc_type).transpose_iter() { let subst_bound = if defs.count() == 0 { bound.subst(tcx, trait_predicate.trait_ref.substs) @@ -598,17 +596,19 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { fn confirm_fn_pointer_candidate( &mut self, obligation: &TraitObligation<'tcx>, + is_const: bool, ) -> Result<ImplSourceFnPointerData<'tcx, PredicateObligation<'tcx>>, SelectionError<'tcx>> { debug!(?obligation, "confirm_fn_pointer_candidate"); + let tcx = self.tcx(); let self_ty = self .infcx .shallow_resolve(obligation.self_ty().no_bound_vars()) .expect("fn pointer should not capture bound vars from predicate"); - let sig = self_ty.fn_sig(self.tcx()); + let sig = self_ty.fn_sig(tcx); let trait_ref = closure_trait_ref_and_return_type( - self.tcx(), + tcx, obligation.predicate.def_id(), self_ty, sig, @@ -617,9 +617,19 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { .map_bound(|(trait_ref, _)| trait_ref); let mut nested = self.confirm_poly_trait_refs(obligation, trait_ref)?; + let cause = obligation.derived_cause(BuiltinDerivedObligation); + + if obligation.is_const() && !is_const { + // function is a trait method + if let ty::FnDef(def_id, substs) = self_ty.kind() && let Some(trait_id) = tcx.trait_of_item(*def_id) { + let trait_ref = TraitRef::from_method(tcx, trait_id, *substs); + let poly_trait_pred = Binder::dummy(trait_ref).with_constness(ty::BoundConstness::ConstIfConst); + let obligation = Obligation::new(tcx, cause.clone(), obligation.param_env, poly_trait_pred); + nested.push(obligation); + } + } // Confirm the `type Output: Sized;` bound that is present on `FnOnce` - let cause = obligation.derived_cause(BuiltinDerivedObligation); let output_ty = self.infcx.replace_bound_vars_with_placeholders(sig.output()); let output_ty = normalize_with_depth_to( self, @@ -756,8 +766,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { debug!(?closure_def_id, ?trait_ref, ?nested, "confirm closure candidate obligations"); // FIXME: Chalk - - if !self.tcx().sess.opts.unstable_opts.chalk { + if self.tcx().sess.opts.unstable_opts.trait_solver != TraitSolver::Chalk { nested.push(obligation.with( self.tcx(), ty::Binder::dummy(ty::PredicateKind::ClosureKind(closure_def_id, substs, kind)), @@ -1279,7 +1288,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { // If we have a projection type, make sure to normalize it so we replace it // with a fresh infer variable - ty::Projection(..) => { + ty::Alias(ty::Projection, ..) => { let predicate = normalize_with_depth_to( self, obligation.param_env, |