Don't substitute a GAT that has mismatched generics in OpaqueTypeCollector
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38b44eb233
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5344ed23fa
6 changed files with 144 additions and 75 deletions
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@ -65,12 +65,12 @@ pub use self::specialize::{
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pub use self::structural_match::search_for_structural_match_violation;
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pub use self::structural_match::search_for_structural_match_violation;
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pub use self::structural_normalize::StructurallyNormalizeExt;
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pub use self::structural_normalize::StructurallyNormalizeExt;
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pub use self::util::elaborate;
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pub use self::util::elaborate;
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pub use self::util::{
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check_substs_compatible, supertrait_def_ids, supertraits, transitive_bounds,
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transitive_bounds_that_define_assoc_item, SupertraitDefIds,
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};
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pub use self::util::{expand_trait_aliases, TraitAliasExpander};
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pub use self::util::{expand_trait_aliases, TraitAliasExpander};
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pub use self::util::{get_vtable_index_of_object_method, impl_item_is_final, upcast_choices};
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pub use self::util::{get_vtable_index_of_object_method, impl_item_is_final, upcast_choices};
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pub use self::util::{
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supertrait_def_ids, supertraits, transitive_bounds, transitive_bounds_that_define_assoc_item,
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SupertraitDefIds,
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};
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pub use self::chalk_fulfill::FulfillmentContext as ChalkFulfillmentContext;
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pub use self::chalk_fulfill::FulfillmentContext as ChalkFulfillmentContext;
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@ -1,5 +1,6 @@
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//! Code for projecting associated types out of trait references.
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//! Code for projecting associated types out of trait references.
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use super::check_substs_compatible;
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use super::specialization_graph;
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use super::specialization_graph;
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use super::translate_substs;
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use super::translate_substs;
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use super::util;
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use super::util;
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@ -2378,47 +2379,6 @@ fn confirm_impl_candidate<'cx, 'tcx>(
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}
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}
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}
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}
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// Verify that the trait item and its implementation have compatible substs lists
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fn check_substs_compatible<'tcx>(
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tcx: TyCtxt<'tcx>,
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assoc_item: ty::AssocItem,
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substs: ty::SubstsRef<'tcx>,
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) -> bool {
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fn check_substs_compatible_inner<'tcx>(
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tcx: TyCtxt<'tcx>,
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generics: &'tcx ty::Generics,
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args: &'tcx [ty::GenericArg<'tcx>],
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) -> bool {
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if generics.count() != args.len() {
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return false;
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}
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let (parent_args, own_args) = args.split_at(generics.parent_count);
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if let Some(parent) = generics.parent
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&& let parent_generics = tcx.generics_of(parent)
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&& !check_substs_compatible_inner(tcx, parent_generics, parent_args) {
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return false;
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}
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for (param, arg) in std::iter::zip(&generics.params, own_args) {
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match (¶m.kind, arg.unpack()) {
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(ty::GenericParamDefKind::Type { .. }, ty::GenericArgKind::Type(_))
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| (ty::GenericParamDefKind::Const { .. }, ty::GenericArgKind::Const(_)) => {}
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_ => return false,
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}
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}
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true
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}
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let generics = tcx.generics_of(assoc_item.def_id);
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// Chop off any additional substs (RPITIT) substs
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let substs = &substs[0..generics.count().min(substs.len())];
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check_substs_compatible_inner(tcx, generics, substs)
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}
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fn confirm_impl_trait_in_trait_candidate<'tcx>(
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fn confirm_impl_trait_in_trait_candidate<'tcx>(
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selcx: &mut SelectionContext<'_, 'tcx>,
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selcx: &mut SelectionContext<'_, 'tcx>,
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obligation: &ProjectionTyObligation<'tcx>,
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obligation: &ProjectionTyObligation<'tcx>,
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@ -302,3 +302,44 @@ pub enum TupleArgumentsFlag {
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Yes,
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Yes,
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No,
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No,
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}
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}
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// Verify that the trait item and its implementation have compatible substs lists
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pub fn check_substs_compatible<'tcx>(
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tcx: TyCtxt<'tcx>,
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assoc_item: ty::AssocItem,
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substs: ty::SubstsRef<'tcx>,
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) -> bool {
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fn check_substs_compatible_inner<'tcx>(
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tcx: TyCtxt<'tcx>,
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generics: &'tcx ty::Generics,
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args: &'tcx [ty::GenericArg<'tcx>],
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) -> bool {
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if generics.count() != args.len() {
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return false;
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}
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let (parent_args, own_args) = args.split_at(generics.parent_count);
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if let Some(parent) = generics.parent
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&& let parent_generics = tcx.generics_of(parent)
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&& !check_substs_compatible_inner(tcx, parent_generics, parent_args) {
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return false;
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}
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for (param, arg) in std::iter::zip(&generics.params, own_args) {
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match (¶m.kind, arg.unpack()) {
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(ty::GenericParamDefKind::Type { .. }, ty::GenericArgKind::Type(_))
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| (ty::GenericParamDefKind::Lifetime, ty::GenericArgKind::Lifetime(_))
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| (ty::GenericParamDefKind::Const { .. }, ty::GenericArgKind::Const(_)) => {}
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_ => return false,
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}
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}
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true
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}
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let generics = tcx.generics_of(assoc_item.def_id);
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// Chop off any additional substs (RPITIT) substs
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let substs = &substs[0..generics.count().min(substs.len())];
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check_substs_compatible_inner(tcx, generics, substs)
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}
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@ -6,7 +6,7 @@ use rustc_middle::ty::util::{CheckRegions, NotUniqueParam};
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use rustc_middle::ty::{self, Ty, TyCtxt};
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use rustc_middle::ty::{self, Ty, TyCtxt};
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use rustc_middle::ty::{TypeSuperVisitable, TypeVisitable, TypeVisitor};
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use rustc_middle::ty::{TypeSuperVisitable, TypeVisitable, TypeVisitor};
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use rustc_span::Span;
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use rustc_span::Span;
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use rustc_type_ir::AliasKind;
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use rustc_trait_selection::traits::check_substs_compatible;
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use std::ops::ControlFlow;
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use std::ops::ControlFlow;
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use crate::errors::{DuplicateArg, NotParam};
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use crate::errors::{DuplicateArg, NotParam};
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@ -36,6 +36,15 @@ impl<'tcx> OpaqueTypeCollector<'tcx> {
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self.tcx.def_span(self.item)
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self.tcx.def_span(self.item)
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}
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}
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fn parent_trait_ref(&self) -> Option<ty::TraitRef<'tcx>> {
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let parent = self.parent()?;
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if matches!(self.tcx.def_kind(parent), DefKind::Impl { .. }) {
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Some(self.tcx.impl_trait_ref(parent)?.subst_identity())
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} else {
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None
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}
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}
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fn parent(&self) -> Option<LocalDefId> {
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fn parent(&self) -> Option<LocalDefId> {
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match self.tcx.def_kind(self.item) {
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match self.tcx.def_kind(self.item) {
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DefKind::Fn => None,
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DefKind::Fn => None,
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@ -56,7 +65,7 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for OpaqueTypeCollector<'tcx> {
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#[instrument(skip(self), ret, level = "trace")]
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#[instrument(skip(self), ret, level = "trace")]
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fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<ErrorGuaranteed> {
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fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<ErrorGuaranteed> {
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match t.kind() {
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match t.kind() {
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ty::Alias(AliasKind::Opaque, alias_ty) if alias_ty.def_id.is_local() => {
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ty::Alias(ty::Opaque, alias_ty) if alias_ty.def_id.is_local() => {
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if !self.seen.insert(alias_ty.def_id.expect_local()) {
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if !self.seen.insert(alias_ty.def_id.expect_local()) {
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return ControlFlow::Continue(());
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return ControlFlow::Continue(());
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}
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}
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@ -98,37 +107,48 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for OpaqueTypeCollector<'tcx> {
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}
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}
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}
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}
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}
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}
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ty::Alias(AliasKind::Projection, alias_ty) => {
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ty::Alias(ty::Projection, alias_ty) => {
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if let Some(parent) = self.parent() {
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// This avoids having to do normalization of `Self::AssocTy` by only
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trace!(?alias_ty);
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// supporting the case of a method defining opaque types from assoc types
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let (trait_ref, own_substs) = alias_ty.trait_ref_and_own_substs(self.tcx);
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// in the same impl block.
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if let Some(parent_trait_ref) = self.parent_trait_ref() {
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// If the trait ref of the associated item and the impl differs,
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// then we can't use the impl's identity substitutions below, so
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// just skip.
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if alias_ty.trait_ref(self.tcx) == parent_trait_ref {
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let parent = self.parent().expect("we should have a parent here");
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trace!(?trait_ref, ?own_substs);
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for &assoc in self.tcx.associated_items(parent).in_definition_order() {
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// This avoids having to do normalization of `Self::AssocTy` by only
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// supporting the case of a method defining opaque types from assoc types
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// in the same impl block.
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if trait_ref.self_ty() == self.tcx.type_of(parent).subst_identity() {
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for assoc in self.tcx.associated_items(parent).in_definition_order() {
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trace!(?assoc);
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trace!(?assoc);
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if assoc.trait_item_def_id == Some(alias_ty.def_id) {
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if assoc.trait_item_def_id != Some(alias_ty.def_id) {
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// We reconstruct the generic args of the associated type within the impl
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continue;
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// from the impl's generics and the generic args passed to the type via the
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// projection.
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let substs = ty::InternalSubsts::identity_for_item(
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self.tcx,
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parent.to_def_id(),
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);
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trace!(?substs);
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let substs: Vec<_> =
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substs.iter().chain(own_substs.iter().copied()).collect();
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trace!(?substs);
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// Find opaque types in this associated type.
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return self
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.tcx
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.type_of(assoc.def_id)
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.subst(self.tcx, &substs)
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.visit_with(self);
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}
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}
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// If the type is further specializable, then the type_of
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// is not actually correct below.
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if !assoc.defaultness(self.tcx).is_final() {
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continue;
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}
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let impl_substs = alias_ty.substs.rebase_onto(
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self.tcx,
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parent_trait_ref.def_id,
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ty::InternalSubsts::identity_for_item(self.tcx, parent),
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);
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if !check_substs_compatible(self.tcx, assoc, impl_substs) {
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self.tcx.sess.delay_span_bug(
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self.tcx.def_span(assoc.def_id),
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"item had incorrect substs",
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);
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return ControlFlow::Continue(());
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}
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return self
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.tcx
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.type_of(assoc.def_id)
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.subst(self.tcx, impl_substs)
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.visit_with(self);
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}
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}
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}
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}
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}
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}
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@ -0,0 +1,28 @@
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#![feature(impl_trait_in_assoc_type)]
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// We weren't checking that the trait and impl generics line up in the
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// normalization-shortcut code in `OpaqueTypeCollector`.
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use std::ops::Deref;
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trait Foo {
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type Bar<'a>;
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type Baz<'a>;
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fn test<'a>() -> Self::Bar<'a>;
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}
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impl Foo for () {
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type Bar<'a> = impl Deref<Target = Self::Baz<'a>>;
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type Baz<T> = impl Sized;
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//~^ ERROR type `Baz` has 1 type parameter but its trait declaration has 0 type parameters
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//~| ERROR unconstrained opaque type
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fn test<'a>() -> Self::Bar<'a> {
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&()
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}
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}
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fn main() {}
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@ -0,0 +1,20 @@
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error[E0049]: type `Baz` has 1 type parameter but its trait declaration has 0 type parameters
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--> $DIR/impl-trait-in-type-alias-with-bad-substs.rs:19:14
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LL | type Baz<'a>;
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...
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LL | type Baz<T> = impl Sized;
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| ^ found 1 type parameter
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error: unconstrained opaque type
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--> $DIR/impl-trait-in-type-alias-with-bad-substs.rs:19:19
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LL | type Baz<T> = impl Sized;
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| ^^^^^^^^^^
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= note: `Baz` must be used in combination with a concrete type within the same impl
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error: aborting due to 2 previous errors
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For more information about this error, try `rustc --explain E0049`.
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