Unrolled build for rust-lang#133218

Rollup merge of rust-lang#133218 - compiler-errors:const-opaque, r=fee1-dead

Implement `~const` item bounds in RPIT

an RPIT in a `const fn` is allowed to be conditionally const itself :)

r? fee1-dead or reroll

Author: rust-timer

compiler/rustc_hir_analysis/src/check/check.rs

@@ -339,6 +339,8 @@ fn check_opaque_meets_bounds<'tcx>(
 
     let misc_cause = ObligationCause::misc(span, def_id);
     // FIXME: We should just register the item bounds here, rather than equating.
+    // FIXME(const_trait_impl): When we do that, please make sure to also register
+    // the `~const` bounds.
     match ocx.eq(&misc_cause, param_env, opaque_ty, hidden_ty) {
         Ok(()) => {}
         Err(ty_err) => {

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -2083,7 +2083,7 @@ pub(super) fn check_type_bounds<'tcx>(
     // Only in a const implementation do we need to check that the `~const` item bounds hold.
     if tcx.is_conditionally_const(impl_ty_def_id) {
         obligations.extend(
-            tcx.implied_const_bounds(trait_ty.def_id)
+            tcx.explicit_implied_const_bounds(trait_ty.def_id)
                 .iter_instantiated_copied(tcx, rebased_args)
                 .map(|(c, span)| {
                     traits::Obligation::new(

compiler/rustc_hir_analysis/src/collect.rs

@@ -78,7 +78,7 @@ pub fn provide(providers: &mut Providers) {
             predicates_of::explicit_supertraits_containing_assoc_item,
         trait_explicit_predicates_and_bounds: predicates_of::trait_explicit_predicates_and_bounds,
         const_conditions: predicates_of::const_conditions,
-        implied_const_bounds: predicates_of::implied_const_bounds,
+        explicit_implied_const_bounds: predicates_of::explicit_implied_const_bounds,
         type_param_predicates: predicates_of::type_param_predicates,
         trait_def,
         adt_def,
@@ -340,6 +340,10 @@ impl<'tcx> Visitor<'tcx> for CollectItemTypesVisitor<'tcx> {
         self.tcx.ensure().explicit_item_super_predicates(def_id);
         self.tcx.ensure().item_bounds(def_id);
         self.tcx.ensure().item_super_predicates(def_id);
+        if self.tcx.is_conditionally_const(def_id) {
+            self.tcx.ensure().explicit_implied_const_bounds(def_id);
+            self.tcx.ensure().const_conditions(def_id);
+        }
         intravisit::walk_opaque_ty(self, opaque);
     }
 
@@ -682,6 +686,10 @@ fn lower_item(tcx: TyCtxt<'_>, item_id: hir::ItemId) {
                 tcx.ensure().generics_of(item.owner_id);
                 tcx.ensure().type_of(item.owner_id);
                 tcx.ensure().predicates_of(item.owner_id);
+                if tcx.is_conditionally_const(def_id) {
+                    tcx.ensure().explicit_implied_const_bounds(def_id);
+                    tcx.ensure().const_conditions(def_id);
+                }
                 match item.kind {
                     hir::ForeignItemKind::Fn(..) => {
                         tcx.ensure().codegen_fn_attrs(item.owner_id);

compiler/rustc_hir_analysis/src/collect/predicates_of.rs

@@ -959,6 +959,12 @@ pub(super) fn const_conditions<'tcx>(
             hir::ForeignItemKind::Fn(_, _, generics) => (generics, None, false),
             _ => bug!("const_conditions called on wrong item: {def_id:?}"),
         },
+        Node::OpaqueTy(opaque) => match opaque.origin {
+            hir::OpaqueTyOrigin::FnReturn { parent, .. } => return tcx.const_conditions(parent),
+            hir::OpaqueTyOrigin::AsyncFn { .. } | hir::OpaqueTyOrigin::TyAlias { .. } => {
+                unreachable!()
+            }
+        },
         // N.B. Tuple ctors are unconditionally constant.
         Node::Ctor(hir::VariantData::Tuple { .. }) => return Default::default(),
         _ => bug!("const_conditions called on wrong item: {def_id:?}"),
@@ -1018,7 +1024,7 @@ pub(super) fn const_conditions<'tcx>(
     }
 }
 
-pub(super) fn implied_const_bounds<'tcx>(
+pub(super) fn explicit_implied_const_bounds<'tcx>(
     tcx: TyCtxt<'tcx>,
     def_id: LocalDefId,
 ) -> ty::EarlyBinder<'tcx, &'tcx [(ty::PolyTraitRef<'tcx>, Span)]> {
@@ -1034,10 +1040,11 @@ pub(super) fn implied_const_bounds<'tcx>(
                 PredicateFilter::SelfConstIfConst,
             )
         }
-        Node::TraitItem(hir::TraitItem { kind: hir::TraitItemKind::Type(..), .. }) => {
+        Node::TraitItem(hir::TraitItem { kind: hir::TraitItemKind::Type(..), .. })
+        | Node::OpaqueTy(_) => {
             explicit_item_bounds_with_filter(tcx, def_id, PredicateFilter::ConstIfConst)
         }
-        _ => bug!("implied_const_bounds called on wrong item: {def_id:?}"),
+        _ => bug!("explicit_implied_const_bounds called on wrong item: {def_id:?}"),
     };
 
     bounds.map_bound(|bounds| {

compiler/rustc_infer/src/infer/opaque_types/mod.rs

@@ -574,9 +574,8 @@ impl<'tcx> InferCtxt<'tcx> {
         // unexpected region errors.
         goals.push(Goal::new(tcx, param_env, ty::ClauseKind::WellFormed(hidden_ty.into())));
 
-        let item_bounds = tcx.explicit_item_bounds(def_id);
-        for (predicate, _) in item_bounds.iter_instantiated_copied(tcx, args) {
-            let predicate = predicate.fold_with(&mut BottomUpFolder {
+        let replace_opaques_in = |clause: ty::Clause<'tcx>, goals: &mut Vec<_>| {
+            clause.fold_with(&mut BottomUpFolder {
                 tcx,
                 ty_op: |ty| match *ty.kind() {
                     // We can't normalize associated types from `rustc_infer`,
@@ -612,11 +611,31 @@ impl<'tcx> InferCtxt<'tcx> {
                 },
                 lt_op: |lt| lt,
                 ct_op: |ct| ct,
-            });
+            })
+        };
+
+        let item_bounds = tcx.explicit_item_bounds(def_id);
+        for (predicate, _) in item_bounds.iter_instantiated_copied(tcx, args) {
+            let predicate = replace_opaques_in(predicate, goals);
 
             // Require that the predicate holds for the concrete type.
             debug!(?predicate);
             goals.push(Goal::new(self.tcx, param_env, predicate));
         }
+
+        // If this opaque is being defined and it's conditionally const,
+        if self.tcx.is_conditionally_const(def_id) {
+            let item_bounds = tcx.explicit_implied_const_bounds(def_id);
+            for (predicate, _) in item_bounds.iter_instantiated_copied(tcx, args) {
+                let predicate = replace_opaques_in(
+                    predicate.to_host_effect_clause(self.tcx, ty::BoundConstness::Maybe),
+                    goals,
+                );
+
+                // Require that the predicate holds for the concrete type.
+                debug!(?predicate);
+                goals.push(Goal::new(self.tcx, param_env, predicate));
+            }
+        }
     }
 }

compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs

@@ -275,7 +275,7 @@ provide! { tcx, def_id, other, cdata,
     defaultness => { table_direct }
     constness => { table_direct }
     const_conditions => { table }
-    implied_const_bounds => { table_defaulted_array }
+    explicit_implied_const_bounds => { table_defaulted_array }
     coerce_unsized_info => {
         Ok(cdata
             .root

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -1463,8 +1463,8 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 record_array!(self.tables.module_children_non_reexports[def_id] <-
                     module_children.iter().map(|child| child.res.def_id().index));
                 if self.tcx.is_const_trait(def_id) {
-                    record_defaulted_array!(self.tables.implied_const_bounds[def_id]
-                        <- self.tcx.implied_const_bounds(def_id).skip_binder());
+                    record_defaulted_array!(self.tables.explicit_implied_const_bounds[def_id]
+                        <- self.tcx.explicit_implied_const_bounds(def_id).skip_binder());
                 }
             }
             if let DefKind::TraitAlias = def_kind {
@@ -1532,6 +1532,10 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 self.encode_explicit_item_super_predicates(def_id);
                 record!(self.tables.opaque_ty_origin[def_id] <- self.tcx.opaque_ty_origin(def_id));
                 self.encode_precise_capturing_args(def_id);
+                if tcx.is_conditionally_const(def_id) {
+                    record_defaulted_array!(self.tables.explicit_implied_const_bounds[def_id]
+                        <- tcx.explicit_implied_const_bounds(def_id).skip_binder());
+                }
             }
             if tcx.impl_method_has_trait_impl_trait_tys(def_id)
                 && let Ok(table) = self.tcx.collect_return_position_impl_trait_in_trait_tys(def_id)
@@ -1654,8 +1658,8 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                     self.encode_explicit_item_bounds(def_id);
                     self.encode_explicit_item_super_predicates(def_id);
                     if tcx.is_conditionally_const(def_id) {
-                        record_defaulted_array!(self.tables.implied_const_bounds[def_id]
-                            <- self.tcx.implied_const_bounds(def_id).skip_binder());
+                        record_defaulted_array!(self.tables.explicit_implied_const_bounds[def_id]
+                            <- self.tcx.explicit_implied_const_bounds(def_id).skip_binder());
                     }
                 }
             }

compiler/rustc_metadata/src/rmeta/mod.rs

@@ -391,7 +391,7 @@ define_tables! {
     inferred_outlives_of: Table<DefIndex, LazyArray<(ty::Clause<'static>, Span)>>,
     explicit_super_predicates_of: Table<DefIndex, LazyArray<(ty::Clause<'static>, Span)>>,
     explicit_implied_predicates_of: Table<DefIndex, LazyArray<(ty::Clause<'static>, Span)>>,
-    implied_const_bounds: Table<DefIndex, LazyArray<(ty::PolyTraitRef<'static>, Span)>>,
+    explicit_implied_const_bounds: Table<DefIndex, LazyArray<(ty::PolyTraitRef<'static>, Span)>>,
     inherent_impls: Table<DefIndex, LazyArray<DefIndex>>,
     associated_types_for_impl_traits_in_associated_fn: Table<DefIndex, LazyArray<DefId>>,
     opt_rpitit_info: Table<DefIndex, Option<LazyValue<ty::ImplTraitInTraitData>>>,

compiler/rustc_middle/src/query/mod.rs

@@ -697,7 +697,7 @@ rustc_queries! {
         separate_provide_extern
     }
 
-    query implied_const_bounds(
+    query explicit_implied_const_bounds(
         key: DefId
     ) -> ty::EarlyBinder<'tcx, &'tcx [(ty::PolyTraitRef<'tcx>, Span)]> {
         desc { |tcx| "computing the implied `~const` bounds for `{}`",

compiler/rustc_middle/src/ty/context.rs

@@ -393,12 +393,12 @@ impl<'tcx> Interner for TyCtxt<'tcx> {
         )
     }
 
-    fn implied_const_bounds(
+    fn explicit_implied_const_bounds(
         self,
         def_id: DefId,
     ) -> ty::EarlyBinder<'tcx, impl IntoIterator<Item = ty::Binder<'tcx, ty::TraitRef<'tcx>>>> {
         ty::EarlyBinder::bind(
-            self.implied_const_bounds(def_id).iter_identity_copied().map(|(c, _)| c),
+            self.explicit_implied_const_bounds(def_id).iter_identity_copied().map(|(c, _)| c),
         )
     }