Finish uplifting supertraits

compiler/rustc_next_trait_solver/src/delegate.rs

@@ -32,12 +32,6 @@ pub trait SolverDelegate:
     // FIXME: Uplift the leak check into this crate.
     fn leak_check(&self, max_input_universe: ty::UniverseIndex) -> Result<(), NoSolution>;
 
-    // FIXME: This is only here because elaboration lives in `rustc_infer`!
-    fn elaborate_supertraits(
-        cx: Self::Interner,
-        trait_ref: ty::Binder<Self::Interner, ty::TraitRef<Self::Interner>>,
-    ) -> impl Iterator<Item = ty::Binder<Self::Interner, ty::TraitRef<Self::Interner>>>;
-
     fn try_const_eval_resolve(
         &self,
         param_env: <Self::Interner as Interner>::ParamEnv,

compiler/rustc_next_trait_solver/src/solve/assembly/mod.rs

@@ -2,6 +2,7 @@
 
 pub(super) mod structural_traits;
 
+use rustc_type_ir::elaborate;
 use rustc_type_ir::fold::TypeFoldable;
 use rustc_type_ir::inherent::*;
 use rustc_type_ir::lang_items::TraitSolverLangItem;
@@ -667,7 +668,7 @@ where
         // a projection goal.
         if let Some(principal) = bounds.principal() {
             let principal_trait_ref = principal.with_self_ty(cx, self_ty);
-            for (idx, assumption) in D::elaborate_supertraits(cx, principal_trait_ref).enumerate() {
+            for (idx, assumption) in elaborate::supertraits(cx, principal_trait_ref).enumerate() {
                 candidates.extend(G::probe_and_consider_object_bound_candidate(
                     self,
                     CandidateSource::BuiltinImpl(BuiltinImplSource::Object(idx)),

compiler/rustc_next_trait_solver/src/solve/trait_goals.rs

@@ -787,7 +787,7 @@ where
             ));
         } else if let Some(a_principal) = a_data.principal() {
             for new_a_principal in
-                D::elaborate_supertraits(self.cx(), a_principal.with_self_ty(cx, a_ty)).skip(1)
+                elaborate::supertraits(self.cx(), a_principal.with_self_ty(cx, a_ty)).skip(1)
             {
                 responses.extend(self.consider_builtin_upcast_to_principal(
                     goal,

compiler/rustc_trait_selection/src/solve/delegate.rs

@@ -8,7 +8,6 @@ use rustc_infer::infer::canonical::{
 };
 use rustc_infer::infer::{InferCtxt, RegionVariableOrigin, TyCtxtInferExt};
 use rustc_infer::traits::solve::Goal;
-use rustc_infer::traits::util::supertraits;
 use rustc_infer::traits::{ObligationCause, Reveal};
 use rustc_middle::ty::fold::TypeFoldable;
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitableExt as _};
@@ -82,13 +81,6 @@ impl<'tcx> rustc_next_trait_solver::delegate::SolverDelegate for SolverDelegate<
         self.0.leak_check(max_input_universe, None).map_err(|_| NoSolution)
     }
 
-    fn elaborate_supertraits(
-        interner: TyCtxt<'tcx>,
-        trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>,
-    ) -> impl Iterator<Item = ty::Binder<'tcx, ty::TraitRef<'tcx>>> {
-        supertraits(interner, trait_ref)
-    }
-
     fn try_const_eval_resolve(
         &self,
         param_env: ty::ParamEnv<'tcx>,