3 files changed, 18 insertions, 1 deletions
diff --git a/compiler/rustc_hir_analysis/src/check/check.rs b/compiler/rustc_hir_analysis/src/check/check.rs
index cf8c81c0b08..275100411d3 100644
--- a/compiler/rustc_hir_analysis/src/check/check.rs
+++ b/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) => {
diff --git a/compiler/rustc_hir_analysis/src/collect.rs b/compiler/rustc_hir_analysis/src/collect.rs
index 001118eb8d3..63e90801904 100644
--- a/compiler/rustc_hir_analysis/src/collect.rs
+++ b/compiler/rustc_hir_analysis/src/collect.rs
@@ -339,6 +339,10 @@ 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);
     }
 
@@ -681,6 +685,10 @@ 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);
diff --git a/compiler/rustc_hir_analysis/src/collect/predicates_of.rs b/compiler/rustc_hir_analysis/src/collect/predicates_of.rs
index a675a7fc768..65a419adaa1 100644
--- a/compiler/rustc_hir_analysis/src/collect/predicates_of.rs
+++ b/compiler/rustc_hir_analysis/src/collect/predicates_of.rs
@@ -958,6 +958,12 @@ 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:?}"),
@@ -1033,7 +1039,8 @@ pub(super) fn explicit_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!("explicit_implied_const_bounds called on wrong item: {def_id:?}"),