squash OpaqueTy and ProjectionTy into AliasTy

compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs

@@ -536,10 +536,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             let ty = traits::normalize_projection_type(
                 self,
                 param_env,
-                ty::ProjectionTy {
-                    def_id: tcx.lang_items().deref_target()?,
-                    substs: trait_ref.substs,
-                },
+                ty::AliasTy { def_id: tcx.lang_items().deref_target()?, substs: trait_ref.substs },
                 cause.clone(),
                 0,
                 // We're *intentionally* throwing these away,
@@ -830,7 +827,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             | ty::GeneratorWitness(_)
             | ty::Never
             | ty::Projection(_)
-            | ty::Opaque(ty::OpaqueTy { def_id: _, substs: _ })
+            | ty::Opaque(ty::AliasTy { def_id: _, substs: _ })
             | ty::Param(_)
             | ty::Bound(_, _)
             | ty::Error(_)

compiler/rustc_trait_selection/src/traits/select/confirmation.rs

@@ -156,7 +156,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         let placeholder_trait_predicate = ty::Binder::dummy(placeholder_trait_predicate);
         let (def_id, substs) = match *placeholder_self_ty.kind() {
             ty::Projection(proj) => (proj.def_id, proj.substs),
-            ty::Opaque(ty::OpaqueTy { def_id, substs }) => (def_id, substs),
+            ty::Opaque(ty::AliasTy { def_id, substs }) => (def_id, substs),
             _ => bug!("projection candidate for unexpected type: {:?}", placeholder_self_ty),
         };
 

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -1596,7 +1596,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         let tcx = self.infcx.tcx;
         let (def_id, substs) = match *placeholder_trait_predicate.trait_ref.self_ty().kind() {
             ty::Projection(ref data) => (data.def_id, data.substs),
-            ty::Opaque(ty::OpaqueTy { def_id, substs }) => (def_id, substs),
+            ty::Opaque(ty::AliasTy { def_id, substs }) => (def_id, substs),
             _ => {
                 span_bug!(
                     obligation.cause.span,
@@ -2260,7 +2260,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 t.rebind(def.all_fields().map(|f| f.ty(self.tcx(), substs)).collect())
             }
 
-            ty::Opaque(ty::OpaqueTy { def_id, substs }) => {
+            ty::Opaque(ty::AliasTy { def_id, substs }) => {
                 // We can resolve the `impl Trait` to its concrete type,
                 // which enforces a DAG between the functions requiring
                 // the auto trait bounds in question.