diff --git a/crates/hir-ty/src/layout.rs b/crates/hir-ty/src/layout.rs
index 819bd583de..2d0471d7e5 100644
--- a/crates/hir-ty/src/layout.rs
+++ b/crates/hir-ty/src/layout.rs
@@ -182,7 +182,7 @@ pub fn layout_of_ty_ns_query<'db>(
     };
     let dl = &*target;
     let cx = LayoutCx::new(dl);
-    let infer_ctxt = interner.infer_ctxt().build(TypingMode::non_body_analysis());
+    let infer_ctxt = interner.infer_ctxt().build(TypingMode::PostAnalysis);
     let cause = ObligationCause::dummy();
     let ty = deeply_normalize(infer_ctxt.at(&cause, ParamEnv::empty()), ty).unwrap_or(ty);
     let result = match ty.kind() {
@@ -335,27 +335,6 @@ pub fn layout_of_ty_ns_query<'db>(
             ptr.valid_range_mut().start = 1;
             Layout::scalar(dl, ptr)
         }
-        TyKind::Alias(_, ty) => match ty.def_id {
-            SolverDefId::TypeAliasId(_) => {
-                return Err(LayoutError::HasPlaceholder);
-            }
-            SolverDefId::InternedOpaqueTyId(opaque) => {
-                let impl_trait_id = db.lookup_intern_impl_trait_id(opaque);
-                match impl_trait_id {
-                    crate::ImplTraitId::ReturnTypeImplTrait(func, idx) => {
-                        let infer = db.infer(func.into());
-                        return db.layout_of_ty(infer.type_of_rpit[idx].clone(), trait_env);
-                    }
-                    crate::ImplTraitId::TypeAliasImplTrait(..) => {
-                        return Err(LayoutError::NotImplemented);
-                    }
-                    crate::ImplTraitId::AsyncBlockTypeImplTrait(_, _) => {
-                        return Err(LayoutError::NotImplemented);
-                    }
-                }
-            }
-            _ => unreachable!(),
-        },
         TyKind::Closure(c, args) => {
             let id = match c {
                 SolverDefId::InternedClosureId(id) => id,
@@ -389,7 +368,11 @@ pub fn layout_of_ty_ns_query<'db>(
         }
 
         TyKind::Error(_) => return Err(LayoutError::HasErrorType),
-        TyKind::Placeholder(_) | TyKind::Bound(..) | TyKind::Infer(..) | TyKind::Param(..) => {
+        TyKind::Placeholder(_)
+        | TyKind::Bound(..)
+        | TyKind::Infer(..)
+        | TyKind::Param(..)
+        | TyKind::Alias(..) => {
             return Err(LayoutError::HasPlaceholder);
         }
     };
diff --git a/crates/hir-ty/src/next_solver/interner.rs b/crates/hir-ty/src/next_solver/interner.rs
index 26dc4ba2fd..4fe0b54d68 100644
--- a/crates/hir-ty/src/next_solver/interner.rs
+++ b/crates/hir-ty/src/next_solver/interner.rs
@@ -22,8 +22,8 @@ use rustc_type_ir::inherent::{
 use rustc_type_ir::lang_items::TraitSolverLangItem;
 use rustc_type_ir::solve::SizedTraitKind;
 use rustc_type_ir::{
-    AliasTerm, AliasTermKind, AliasTy, EarlyBinder, FlagComputation, Flags, ImplPolarity, InferTy,
-    ProjectionPredicate, TraitPredicate, TraitRef, Upcast,
+    AliasTerm, AliasTermKind, AliasTy, AliasTyKind, EarlyBinder, FlagComputation, Flags,
+    ImplPolarity, InferTy, ProjectionPredicate, TraitPredicate, TraitRef, Upcast,
 };
 use salsa::plumbing::AsId;
 use smallvec::{SmallVec, smallvec};
@@ -626,12 +626,7 @@ impl<'db> inherent::AdtDef<DbInterner<'db>> for AdtDef {
     fn struct_tail_ty(
         self,
         interner: DbInterner<'db>,
-    ) -> Option<
-        rustc_type_ir::EarlyBinder<
-            DbInterner<'db>,
-            <DbInterner<'db> as rustc_type_ir::Interner>::Ty,
-        >,
-    > {
+    ) -> Option<EarlyBinder<DbInterner<'db>, Ty<'db>>> {
         let db = interner.db();
         let hir_def::AdtId::StructId(struct_id) = self.inner().id else {
             return None;
@@ -645,10 +640,7 @@ impl<'db> inherent::AdtDef<DbInterner<'db>> for AdtDef {
     fn all_field_tys(
         self,
         interner: DbInterner<'db>,
-    ) -> rustc_type_ir::EarlyBinder<
-        DbInterner<'db>,
-        impl IntoIterator<Item = <DbInterner<'db> as rustc_type_ir::Interner>::Ty>,
-    > {
+    ) -> EarlyBinder<DbInterner<'db>, impl IntoIterator<Item = Ty<'db>>> {
         let db = interner.db();
         // FIXME: this is disabled just to match the behavior with chalk right now
         let field_tys = |id: VariantId| {
@@ -679,19 +671,14 @@ impl<'db> inherent::AdtDef<DbInterner<'db>> for AdtDef {
                 .collect(),
         };
 
-        rustc_type_ir::EarlyBinder::bind(tys)
+        EarlyBinder::bind(tys)
     }
 
     fn sizedness_constraint(
         self,
         interner: DbInterner<'db>,
         sizedness: SizedTraitKind,
-    ) -> Option<
-        rustc_type_ir::EarlyBinder<
-            DbInterner<'db>,
-            <DbInterner<'db> as rustc_type_ir::Interner>::Ty,
-        >,
-    > {
+    ) -> Option<EarlyBinder<DbInterner<'db>, Ty<'db>>> {
         if self.is_struct() {
             let tail_ty = self.all_field_tys(interner).skip_binder().into_iter().last()?;
 
@@ -1024,8 +1011,8 @@ impl<'db> rustc_type_ir::Interner for DbInterner<'db> {
         false
     }
 
-    fn expand_abstract_consts<T: rustc_type_ir::TypeFoldable<Self>>(self, t: T) -> T {
-        t
+    fn expand_abstract_consts<T: rustc_type_ir::TypeFoldable<Self>>(self, _: T) -> T {
+        unreachable!("only used by the old trait solver in rustc");
     }
 
     fn generics_of(self, def_id: Self::DefId) -> Self::GenericsOf {
@@ -1054,6 +1041,9 @@ impl<'db> rustc_type_ir::Interner for DbInterner<'db> {
             ),
             SolverDefId::InternedOpaqueTyId(_def_id) => {
                 // FIXME(next-solver): track variances
+                //
+                // We compute them based on the only `Ty` level info in rustc,
+                // move `variances_of_opaque` into `rustc_next_trait_solver` for reuse.
                 VariancesOf::new_from_iter(
                     self,
                     (0..self.generics_of(def_id).count()).map(|_| Variance::Invariant),
@@ -1063,7 +1053,7 @@ impl<'db> rustc_type_ir::Interner for DbInterner<'db> {
         }
     }
 
-    fn type_of(self, def_id: Self::DefId) -> rustc_type_ir::EarlyBinder<Self, Self::Ty> {
+    fn type_of(self, def_id: Self::DefId) -> EarlyBinder<Self, Self::Ty> {
         let def_id = match def_id {
             SolverDefId::TypeAliasId(id) => {
                 use hir_def::Lookup;
@@ -1074,6 +1064,13 @@ impl<'db> rustc_type_ir::Interner for DbInterner<'db> {
                 crate::TyDefId::TypeAliasId(id)
             }
             SolverDefId::AdtId(id) => crate::TyDefId::AdtId(id),
+            // FIXME(next-solver): This uses the types of `query mir_borrowck` in rustc.
+            //
+            // We currently always use the type from HIR typeck which ignores regions. This
+            // should be fine.
+            SolverDefId::InternedOpaqueTyId(_) => {
+                return self.type_of_opaque_hir_typeck(def_id);
+            }
             _ => panic!("Unexpected def_id `{def_id:?}` provided for `type_of`"),
         };
         self.db().ty_ns(def_id)
@@ -1087,9 +1084,12 @@ impl<'db> rustc_type_ir::Interner for DbInterner<'db> {
         AdtDef::new(def_id, self)
     }
 
-    fn alias_ty_kind(self, alias: rustc_type_ir::AliasTy<Self>) -> rustc_type_ir::AliasTyKind {
-        // FIXME: not currently creating any others
-        rustc_type_ir::AliasTyKind::Projection
+    fn alias_ty_kind(self, alias: rustc_type_ir::AliasTy<Self>) -> AliasTyKind {
+        match alias.def_id {
+            SolverDefId::InternedOpaqueTyId(_) => AliasTyKind::Opaque,
+            SolverDefId::TypeAliasId(_) => AliasTyKind::Projection,
+            _ => unimplemented!("Unexpected alias: {:?}", alias.def_id),
+        }
     }
 
     fn alias_term_kind(
@@ -1100,7 +1100,7 @@ impl<'db> rustc_type_ir::Interner for DbInterner<'db> {
             SolverDefId::InternedOpaqueTyId(_) => AliasTermKind::OpaqueTy,
             SolverDefId::TypeAliasId(_) => AliasTermKind::ProjectionTy,
             SolverDefId::ConstId(_) => AliasTermKind::UnevaluatedConst,
-            _ => unreachable!("Unexpected alias: {:?}", alias.def_id),
+            _ => unimplemented!("Unexpected alias: {:?}", alias.def_id),
         }
     }
 
@@ -1194,8 +1194,7 @@ impl<'db> rustc_type_ir::Interner for DbInterner<'db> {
     fn fn_sig(
         self,
         def_id: Self::DefId,
-    ) -> rustc_type_ir::EarlyBinder<Self, rustc_type_ir::Binder<Self, rustc_type_ir::FnSig<Self>>>
-    {
+    ) -> EarlyBinder<Self, rustc_type_ir::Binder<Self, rustc_type_ir::FnSig<Self>>> {
         let id = match def_id {
             SolverDefId::FunctionId(id) => CallableDefId::FunctionId(id),
             SolverDefId::Ctor(ctor) => match ctor {
@@ -1248,7 +1247,7 @@ impl<'db> rustc_type_ir::Interner for DbInterner<'db> {
     fn item_bounds(
         self,
         def_id: Self::DefId,
-    ) -> rustc_type_ir::EarlyBinder<Self, impl IntoIterator<Item = Self::Clause>> {
+    ) -> EarlyBinder<Self, impl IntoIterator<Item = Self::Clause>> {
         explicit_item_bounds(self, def_id).map_bound(|bounds| {
             Clauses::new_from_iter(self, elaborate(self, bounds).collect::<Vec<_>>())
         })
@@ -1258,7 +1257,7 @@ impl<'db> rustc_type_ir::Interner for DbInterner<'db> {
     fn item_self_bounds(
         self,
         def_id: Self::DefId,
-    ) -> rustc_type_ir::EarlyBinder<Self, impl IntoIterator<Item = Self::Clause>> {
+    ) -> EarlyBinder<Self, impl IntoIterator<Item = Self::Clause>> {
         explicit_item_bounds(self, def_id).map_bound(|bounds| {
             Clauses::new_from_iter(
                 self,
@@ -1270,7 +1269,7 @@ impl<'db> rustc_type_ir::Interner for DbInterner<'db> {
     fn item_non_self_bounds(
         self,
         def_id: Self::DefId,
-    ) -> rustc_type_ir::EarlyBinder<Self, impl IntoIterator<Item = Self::Clause>> {
+    ) -> EarlyBinder<Self, impl IntoIterator<Item = Self::Clause>> {
         let all_bounds: FxHashSet<_> = self.item_bounds(def_id).skip_binder().into_iter().collect();
         let own_bounds: FxHashSet<_> =
             self.item_self_bounds(def_id).skip_binder().into_iter().collect();
@@ -1288,7 +1287,7 @@ impl<'db> rustc_type_ir::Interner for DbInterner<'db> {
     fn predicates_of(
         self,
         def_id: Self::DefId,
-    ) -> rustc_type_ir::EarlyBinder<Self, impl IntoIterator<Item = Self::Clause>> {
+    ) -> EarlyBinder<Self, impl IntoIterator<Item = Self::Clause>> {
         let predicates = self.db().generic_predicates_ns(def_id.try_into().unwrap());
         let predicates: Vec<_> = predicates.iter().cloned().collect();
         EarlyBinder::bind(predicates.into_iter())
@@ -1298,7 +1297,7 @@ impl<'db> rustc_type_ir::Interner for DbInterner<'db> {
     fn own_predicates_of(
         self,
         def_id: Self::DefId,
-    ) -> rustc_type_ir::EarlyBinder<Self, impl IntoIterator<Item = Self::Clause>> {
+    ) -> EarlyBinder<Self, impl IntoIterator<Item = Self::Clause>> {
         let predicates = self.db().generic_predicates_without_parent_ns(def_id.try_into().unwrap());
         let predicates: Vec<_> = predicates.iter().cloned().collect();
         EarlyBinder::bind(predicates.into_iter())
@@ -1308,8 +1307,7 @@ impl<'db> rustc_type_ir::Interner for DbInterner<'db> {
     fn explicit_super_predicates_of(
         self,
         def_id: Self::DefId,
-    ) -> rustc_type_ir::EarlyBinder<Self, impl IntoIterator<Item = (Self::Clause, Self::Span)>>
-    {
+    ) -> EarlyBinder<Self, impl IntoIterator<Item = (Self::Clause, Self::Span)>> {
         let predicates: Vec<(Clause<'db>, Span)> = self
             .db()
             .generic_predicates_ns(def_id.try_into().unwrap())
@@ -1317,15 +1315,14 @@ impl<'db> rustc_type_ir::Interner for DbInterner<'db> {
             .cloned()
             .map(|p| (p, Span::dummy()))
             .collect();
-        rustc_type_ir::EarlyBinder::bind(predicates)
+        EarlyBinder::bind(predicates)
     }
 
     #[tracing::instrument(skip(self), ret)]
     fn explicit_implied_predicates_of(
         self,
         def_id: Self::DefId,
-    ) -> rustc_type_ir::EarlyBinder<Self, impl IntoIterator<Item = (Self::Clause, Self::Span)>>
-    {
+    ) -> EarlyBinder<Self, impl IntoIterator<Item = (Self::Clause, Self::Span)>> {
         let predicates: Vec<(Clause<'db>, Span)> = self
             .db()
             .generic_predicates_ns(def_id.try_into().unwrap())
@@ -1333,13 +1330,13 @@ impl<'db> rustc_type_ir::Interner for DbInterner<'db> {
             .cloned()
             .map(|p| (p, Span::dummy()))
             .collect();
-        rustc_type_ir::EarlyBinder::bind(predicates)
+        EarlyBinder::bind(predicates)
     }
 
     fn impl_super_outlives(
         self,
         impl_def_id: Self::DefId,
-    ) -> rustc_type_ir::EarlyBinder<Self, impl IntoIterator<Item = Self::Clause>> {
+    ) -> EarlyBinder<Self, impl IntoIterator<Item = Self::Clause>> {
         let impl_id = match impl_def_id {
             SolverDefId::ImplId(id) => id,
             _ => unreachable!(),
@@ -1362,11 +1359,11 @@ impl<'db> rustc_type_ir::Interner for DbInterner<'db> {
     fn const_conditions(
         self,
         def_id: Self::DefId,
-    ) -> rustc_type_ir::EarlyBinder<
+    ) -> EarlyBinder<
         Self,
         impl IntoIterator<Item = rustc_type_ir::Binder<Self, rustc_type_ir::TraitRef<Self>>>,
     > {
-        rustc_type_ir::EarlyBinder::bind([unimplemented!()])
+        EarlyBinder::bind([unimplemented!()])
     }
 
     fn has_target_features(self, def_id: Self::DefId) -> bool {
@@ -1740,7 +1737,7 @@ impl<'db> rustc_type_ir::Interner for DbInterner<'db> {
     }
 
     fn has_item_definition(self, def_id: Self::DefId) -> bool {
-        // FIXME: should check if has value
+        // FIXME(next-solver): should check if the associated item has a value.
         true
     }
 
@@ -1753,7 +1750,7 @@ impl<'db> rustc_type_ir::Interner for DbInterner<'db> {
     fn impl_trait_ref(
         self,
         impl_def_id: Self::DefId,
-    ) -> rustc_type_ir::EarlyBinder<Self, rustc_type_ir::TraitRef<Self>> {
+    ) -> EarlyBinder<Self, rustc_type_ir::TraitRef<Self>> {
         let impl_id = match impl_def_id {
             SolverDefId::ImplId(id) => id,
             _ => panic!("Unexpected SolverDefId in impl_trait_ref"),
@@ -1815,7 +1812,8 @@ impl<'db> rustc_type_ir::Interner for DbInterner<'db> {
     }
 
     fn trait_may_be_implemented_via_object(self, trait_def_id: Self::DefId) -> bool {
-        // FIXME(next-solver)
+        // FIXME(next-solver): should check the `TraitFlags` for
+        // the `#[rustc_do_not_implement_via_object]` flag
         true
     }
 
@@ -1954,12 +1952,12 @@ impl<'db> rustc_type_ir::Interner for DbInterner<'db> {
     fn explicit_implied_const_bounds(
         self,
         def_id: Self::DefId,
-    ) -> rustc_type_ir::EarlyBinder<
+    ) -> EarlyBinder<
         Self,
         impl IntoIterator<Item = rustc_type_ir::Binder<Self, rustc_type_ir::TraitRef<Self>>>,
     > {
         // FIXME(next-solver)
-        rustc_type_ir::EarlyBinder::bind([])
+        EarlyBinder::bind([])
     }
 
     fn fn_is_const(self, def_id: Self::DefId) -> bool {
@@ -1982,21 +1980,31 @@ impl<'db> rustc_type_ir::Interner for DbInterner<'db> {
         None
     }
 
-    fn type_of_opaque_hir_typeck(
-        self,
-        def_id: Self::LocalDefId,
-    ) -> rustc_type_ir::EarlyBinder<Self, Self::Ty> {
-        // FIXME(next-solver)
-        unimplemented!()
+    fn type_of_opaque_hir_typeck(self, def_id: Self::LocalDefId) -> EarlyBinder<Self, Self::Ty> {
+        match def_id {
+            SolverDefId::InternedOpaqueTyId(opaque) => {
+                let impl_trait_id = self.db().lookup_intern_impl_trait_id(opaque);
+                match impl_trait_id {
+                    crate::ImplTraitId::ReturnTypeImplTrait(func, idx) => {
+                        let infer = self.db().infer(func.into());
+                        EarlyBinder::bind(infer.type_of_rpit[idx].to_nextsolver(self))
+                    }
+                    crate::ImplTraitId::TypeAliasImplTrait(..)
+                    | crate::ImplTraitId::AsyncBlockTypeImplTrait(_, _) => {
+                        // FIXME(next-solver)
+                        EarlyBinder::bind(Ty::new_error(self, ErrorGuaranteed))
+                    }
+                }
+            }
+            _ => panic!("Unexpected SolverDefId in type_of_opaque_hir_typeck"),
+        }
     }
 
     fn coroutine_hidden_types(
         self,
         def_id: Self::DefId,
-    ) -> rustc_type_ir::EarlyBinder<
-        Self,
-        rustc_type_ir::Binder<Self, rustc_type_ir::CoroutineWitnessTypes<Self>>,
-    > {
+    ) -> EarlyBinder<Self, rustc_type_ir::Binder<Self, rustc_type_ir::CoroutineWitnessTypes<Self>>>
+    {
         // FIXME(next-solver)
         unimplemented!()
     }
diff --git a/crates/hir-ty/src/tests.rs b/crates/hir-ty/src/tests.rs
index c5f78e2f3c..d98b6602ef 100644
--- a/crates/hir-ty/src/tests.rs
+++ b/crates/hir-ty/src/tests.rs
@@ -6,12 +6,12 @@ mod incremental;
 mod macros;
 mod method_resolution;
 mod never_type;
+mod opaque_types;
 mod patterns;
 mod regression;
 mod simple;
 mod trait_aliases;
 mod traits;
-mod type_alias_impl_traits;
 
 use base_db::{Crate, SourceDatabase};
 use expect_test::Expect;
diff --git a/crates/hir-ty/src/tests/type_alias_impl_traits.rs b/crates/hir-ty/src/tests/opaque_types.rs
similarity index 92%
rename from crates/hir-ty/src/tests/type_alias_impl_traits.rs
rename to crates/hir-ty/src/tests/opaque_types.rs
index e2b7bf379c..36578545a9 100644
--- a/crates/hir-ty/src/tests/type_alias_impl_traits.rs
+++ b/crates/hir-ty/src/tests/opaque_types.rs
@@ -159,3 +159,19 @@ static ALIAS: i32 = {
         "#]],
     )
 }
+
+#[test]
+fn leak_auto_traits() {
+    check_no_mismatches(
+        r#"
+//- minicore: send
+fn foo() -> impl Sized {}
+
+fn is_send<T: Send>(_: T) {}
+
+fn main() {
+    is_send(foo());
+}
+        "#,
+    );
+}