diff options
Diffstat (limited to 'compiler/rustc_hir_analysis/src')
| -rw-r--r-- | compiler/rustc_hir_analysis/src/astconv/mod.rs | 153 |
1 files changed, 103 insertions, 50 deletions
diff --git a/compiler/rustc_hir_analysis/src/astconv/mod.rs b/compiler/rustc_hir_analysis/src/astconv/mod.rs index 4ab6bb5908b..0565bc6dffe 100644 --- a/compiler/rustc_hir_analysis/src/astconv/mod.rs +++ b/compiler/rustc_hir_analysis/src/astconv/mod.rs @@ -854,16 +854,15 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o { ) } - fn trait_defines_associated_type_named(&self, trait_def_id: DefId, assoc_name: Ident) -> bool { - self.tcx() - .associated_items(trait_def_id) - .find_by_name_and_kind(self.tcx(), assoc_name, ty::AssocKind::Type, trait_def_id) - .is_some() - } - fn trait_defines_associated_const_named(&self, trait_def_id: DefId, assoc_name: Ident) -> bool { + fn trait_defines_associated_item_named( + &self, + trait_def_id: DefId, + assoc_kind: ty::AssocKind, + assoc_name: Ident, + ) -> bool { self.tcx() .associated_items(trait_def_id) - .find_by_name_and_kind(self.tcx(), assoc_name, ty::AssocKind::Const, trait_def_id) + .find_by_name_and_kind(self.tcx(), assoc_name, assoc_kind, trait_def_id) .is_some() } @@ -1087,24 +1086,42 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o { let tcx = self.tcx(); - let candidate = - if self.trait_defines_associated_type_named(trait_ref.def_id(), binding.item_name) { - // Simple case: X is defined in the current trait. + // TODO: rtn comment goes here + let associated_return_type_bound = + binding.gen_args.parenthesized && self.tcx().features().associated_return_type_bounds; + + let candidate = if return_type_notation { + if self.trait_defines_associated_item_named( + trait_ref.def_id(), + ty::AssocKind::Fn, + binding.item_name, + ) { trait_ref } else { - // Otherwise, we have to walk through the supertraits to find - // those that do. - self.one_bound_for_assoc_type( - || traits::supertraits(tcx, trait_ref), - trait_ref.print_only_trait_path(), - binding.item_name, - path_span, - match binding.kind { - ConvertedBindingKind::Equality(term) => Some(term), - _ => None, - }, - )? - }; + // TODO: error + todo!() + } + } else if self.trait_defines_associated_item_named( + trait_ref.def_id(), + ty::AssocKind::Type, + binding.item_name, + ) { + // Simple case: X is defined in the current trait. + trait_ref + } else { + // Otherwise, we have to walk through the supertraits to find + // those that do. + self.one_bound_for_assoc_type( + || traits::supertraits(tcx, trait_ref), + trait_ref.print_only_trait_path(), + binding.item_name, + path_span, + match binding.kind { + ConvertedBindingKind::Equality(term) => Some(term), + _ => None, + }, + )? + }; let (assoc_ident, def_scope) = tcx.adjust_ident_and_get_scope(binding.item_name, candidate.def_id(), hir_ref_id); @@ -1116,9 +1133,13 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o { .filter_by_name_unhygienic(assoc_ident.name) .find(|i| i.kind == kind && i.ident(tcx).normalize_to_macros_2_0() == assoc_ident) }; - let assoc_item = find_item_of_kind(ty::AssocKind::Type) - .or_else(|| find_item_of_kind(ty::AssocKind::Const)) - .expect("missing associated type"); + let assoc_item = if return_type_notation { + find_item_of_kind(ty::AssocKind::Fn) + } else { + find_item_of_kind(ty::AssocKind::Type) + .or_else(|| find_item_of_kind(ty::AssocKind::Const)) + } + .expect("missing associated type"); if !assoc_item.visibility(tcx).is_accessible_from(def_scope, tcx) { tcx.sess @@ -1145,28 +1166,54 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o { .or_insert(binding.span); } - // Include substitutions for generic parameters of associated types - let projection_ty = candidate.map_bound(|trait_ref| { - let ident = Ident::new(assoc_item.name, binding.item_name.span); - let item_segment = hir::PathSegment { - ident, - hir_id: binding.hir_id, - res: Res::Err, - args: Some(binding.gen_args), - infer_args: false, + let projection_ty = if associated_return_type_bound { + let generics = self.tcx().generics_of(assoc_item.def_id); + if !generics.params.is_empty() { + todo!(); + } + let output = self.tcx().fn_sig(assoc_item.def_id).skip_binder().output(); + let fn_bound_vars = output.bound_vars(); + + let output = if let ty::Alias(ty::Projection, alias_ty) = *output.skip_binder().kind() + && tcx.def_kind(alias_ty.def_id) == DefKind::ImplTraitPlaceholder + { + alias_ty + } else { + todo!("found return type of {output:?}"); }; - let substs_trait_ref_and_assoc_item = self.create_substs_for_associated_item( - path_span, - assoc_item.def_id, - &item_segment, - trait_ref.substs, - ); + let trait_bound_vars = candidate.bound_vars(); + let shifted_output = tcx.shift_bound_var_indices(trait_bound_vars.len(), output); + let subst_output = + ty::EarlyBinder(shifted_output).subst(tcx, candidate.skip_binder().substs); + let bound_vars = + tcx.mk_bound_variable_kinds_from_iter(trait_bound_vars.iter().chain(fn_bound_vars)); + + ty::Binder::bind_with_vars(subst_output, bound_vars) + } else { + // Include substitutions for generic parameters of associated types + candidate.map_bound(|trait_ref| { + let ident = Ident::new(assoc_item.name, binding.item_name.span); + let item_segment = hir::PathSegment { + ident, + hir_id: binding.hir_id, + res: Res::Err, + args: Some(binding.gen_args), + infer_args: false, + }; - debug!(?substs_trait_ref_and_assoc_item); + let substs_trait_ref_and_assoc_item = self.create_substs_for_associated_item( + path_span, + assoc_item.def_id, + &item_segment, + trait_ref.substs, + ); - self.tcx().mk_alias_ty(assoc_item.def_id, substs_trait_ref_and_assoc_item) - }); + debug!(?substs_trait_ref_and_assoc_item); + + self.tcx().mk_alias_ty(assoc_item.def_id, substs_trait_ref_and_assoc_item) + }) + }; if !speculative { // Find any late-bound regions declared in `ty` that are not @@ -1206,6 +1253,10 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o { } match binding.kind { + ConvertedBindingKind::Equality(..) if associated_return_type_bound => { + // TODO: error + todo!() + } ConvertedBindingKind::Equality(mut term) => { // "Desugar" a constraint like `T: Iterator<Item = u32>` this to // the "projection predicate" for: @@ -1267,7 +1318,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o { // Calling `skip_binder` is okay, because `add_bounds` expects the `param_ty` // parameter to have a skipped binder. let param_ty = tcx.mk_alias(ty::Projection, projection_ty.skip_binder()); - self.add_bounds(param_ty, ast_bounds.iter(), bounds, candidate.bound_vars()); + self.add_bounds(param_ty, ast_bounds.iter(), bounds, projection_ty.bound_vars()); } } Ok(()) @@ -1808,10 +1859,12 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o { where I: Iterator<Item = ty::PolyTraitRef<'tcx>>, { - let mut matching_candidates = all_candidates() - .filter(|r| self.trait_defines_associated_type_named(r.def_id(), assoc_name)); - let mut const_candidates = all_candidates() - .filter(|r| self.trait_defines_associated_const_named(r.def_id(), assoc_name)); + let mut matching_candidates = all_candidates().filter(|r| { + self.trait_defines_associated_item_named(r.def_id(), ty::AssocKind::Type, assoc_name) + }); + let mut const_candidates = all_candidates().filter(|r| { + self.trait_defines_associated_item_named(r.def_id(), ty::AssocKind::Const, assoc_name) + }); let (bound, next_cand) = match (matching_candidates.next(), const_candidates.next()) { (Some(bound), _) => (bound, matching_candidates.next()), |