Add bound_impl_subject and bound_return_ty

compiler/rustc_const_eval/src/const_eval/eval_queries.rs

@@ -13,7 +13,7 @@ use rustc_middle::mir::pretty::display_allocation;
 use rustc_middle::traits::Reveal;
 use rustc_middle::ty::layout::LayoutOf;
 use rustc_middle::ty::print::with_no_trimmed_paths;
-use rustc_middle::ty::{self, subst::Subst, EarlyBinder, TyCtxt};
+use rustc_middle::ty::{self, subst::Subst, TyCtxt};
 use rustc_span::source_map::Span;
 use rustc_target::abi::{self, Abi};
 use std::borrow::Cow;
@@ -45,7 +45,7 @@ fn eval_body_using_ecx<'mir, 'tcx>(
         "Unexpected DefKind: {:?}",
         ecx.tcx.def_kind(cid.instance.def_id())
     );
-    let layout = ecx.layout_of(EarlyBinder(body.return_ty()).subst(tcx, cid.instance.substs))?;
+    let layout = ecx.layout_of(body.bound_return_ty().subst(tcx, cid.instance.substs))?;
     assert!(!layout.is_unsized());
     let ret = ecx.allocate(layout, MemoryKind::Stack)?;
 

compiler/rustc_middle/src/mir/mod.rs

@@ -431,6 +431,12 @@ impl<'tcx> Body<'tcx> {
         self.local_decls[RETURN_PLACE].ty
     }
 
+    /// Returns the return type; it always return first element from `local_decls` array.
+    #[inline]
+    pub fn bound_return_ty(&self) -> ty::EarlyBinder<Ty<'tcx>> {
+        ty::EarlyBinder(self.local_decls[RETURN_PLACE].ty)
+    }
+
     /// Gets the location of the terminator for the given block.
     #[inline]
     pub fn terminator_loc(&self, bb: BasicBlock) -> Location {

compiler/rustc_middle/src/ty/util.rs

@@ -694,6 +694,10 @@ impl<'tcx> TyCtxt<'tcx> {
     ) -> ty::EarlyBinder<ty::generics::GenericPredicates<'tcx>> {
         ty::EarlyBinder(self.explicit_predicates_of(def_id))
     }
+
+    pub fn bound_impl_subject(self, def_id: DefId) -> ty::EarlyBinder<ty::ImplSubject<'tcx>> {
+        ty::EarlyBinder(self.impl_subject(def_id))
+    }
 }
 
 struct OpaqueTypeExpander<'tcx> {

compiler/rustc_mir_transform/src/const_prop.rs

@@ -18,9 +18,7 @@ use rustc_middle::mir::{
 };
 use rustc_middle::ty::layout::{LayoutError, LayoutOf, LayoutOfHelpers, TyAndLayout};
 use rustc_middle::ty::subst::{InternalSubsts, Subst};
-use rustc_middle::ty::{
+use rustc_middle::ty::{self, ConstKind, Instance, ParamEnv, Ty, TyCtxt, TypeVisitable};
-    self, ConstKind, EarlyBinder, Instance, ParamEnv, Ty, TyCtxt, TypeVisitable,
-};
 use rustc_span::{def_id::DefId, Span};
 use rustc_target::abi::{self, HasDataLayout, Size, TargetDataLayout};
 use rustc_target::spec::abi::Abi as CallAbi;
@@ -387,7 +385,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
         );
 
         let ret_layout = ecx
-            .layout_of(EarlyBinder(body.return_ty()).subst(tcx, substs))
+            .layout_of(body.bound_return_ty().subst(tcx, substs))
             .ok()
             // Don't bother allocating memory for large values.
             // I don't know how return types can seem to be unsized but this happens in the

compiler/rustc_mir_transform/src/const_prop_lint.rs

@@ -23,8 +23,7 @@ use rustc_middle::mir::{
 use rustc_middle::ty::layout::{LayoutError, LayoutOf, LayoutOfHelpers, TyAndLayout};
 use rustc_middle::ty::subst::{InternalSubsts, Subst};
 use rustc_middle::ty::{
-    self, ConstInt, ConstKind, EarlyBinder, Instance, ParamEnv, ScalarInt, Ty, TyCtxt,
+    self, ConstInt, ConstKind, Instance, ParamEnv, ScalarInt, Ty, TyCtxt, TypeVisitable,
-    TypeVisitable,
 };
 use rustc_session::lint;
 use rustc_span::Span;
@@ -196,7 +195,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
         );
 
         let ret_layout = ecx
-            .layout_of(EarlyBinder(body.return_ty()).subst(tcx, substs))
+            .layout_of(body.bound_return_ty().subst(tcx, substs))
             .ok()
             // Don't bother allocating memory for large values.
             // I don't know how return types can seem to be unsized but this happens in the

compiler/rustc_trait_selection/src/traits/project.rs

@@ -32,7 +32,7 @@ use rustc_middle::traits::select::OverflowError;
 use rustc_middle::ty::fold::{TypeFoldable, TypeFolder, TypeSuperFoldable};
 use rustc_middle::ty::subst::Subst;
 use rustc_middle::ty::visit::{MaxUniverse, TypeVisitable};
-use rustc_middle::ty::{self, EarlyBinder, Term, ToPredicate, Ty, TyCtxt};
+use rustc_middle::ty::{self, Term, ToPredicate, Ty, TyCtxt};
 use rustc_span::symbol::sym;
 
 use std::collections::BTreeMap;
@@ -2005,16 +2005,16 @@ fn confirm_impl_candidate<'cx, 'tcx>(
     let substs = obligation.predicate.substs.rebase_onto(tcx, trait_def_id, substs);
     let substs =
         translate_substs(selcx.infcx(), param_env, impl_def_id, substs, assoc_ty.defining_node);
-    let ty = tcx.type_of(assoc_ty.item.def_id);
+    let ty = tcx.bound_type_of(assoc_ty.item.def_id);
     let is_const = matches!(tcx.def_kind(assoc_ty.item.def_id), DefKind::AssocConst);
-    let term: ty::Term<'tcx> = if is_const {
+    let term: ty::EarlyBinder<ty::Term<'tcx>> = if is_const {
         let identity_substs =
             crate::traits::InternalSubsts::identity_for_item(tcx, assoc_ty.item.def_id);
         let did = ty::WithOptConstParam::unknown(assoc_ty.item.def_id);
         let kind = ty::ConstKind::Unevaluated(ty::Unevaluated::new(did, identity_substs));
-        tcx.mk_const(ty::ConstS { ty, kind }).into()
+        ty.map_bound(|ty| tcx.mk_const(ty::ConstS { ty, kind }).into())
     } else {
-        ty.into()
+        ty.map_bound(|ty| ty.into())
     };
     if substs.len() != tcx.generics_of(assoc_ty.item.def_id).count() {
         let err = tcx.ty_error_with_message(
@@ -2024,7 +2024,7 @@ fn confirm_impl_candidate<'cx, 'tcx>(
         Progress { term: err.into(), obligations: nested }
     } else {
         assoc_ty_own_obligations(selcx, obligation, &mut nested);
-        Progress { term: EarlyBinder(term).subst(tcx, substs), obligations: nested }
+        Progress { term: term.subst(tcx, substs), obligations: nested }
     }
 }
 

compiler/rustc_trait_selection/src/traits/util.rs

@@ -6,7 +6,7 @@ use smallvec::SmallVec;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::def_id::DefId;
 use rustc_middle::ty::subst::{GenericArg, Subst, SubstsRef};
-use rustc_middle::ty::{self, EarlyBinder, ImplSubject, ToPredicate, Ty, TyCtxt, TypeVisitable};
+use rustc_middle::ty::{self, ImplSubject, ToPredicate, Ty, TyCtxt, TypeVisitable};
 
 use super::{Normalized, Obligation, ObligationCause, PredicateObligation, SelectionContext};
 pub use rustc_infer::traits::{self, util::*};
@@ -200,8 +200,8 @@ pub fn impl_subject_and_oblig<'a, 'tcx>(
     impl_def_id: DefId,
     impl_substs: SubstsRef<'tcx>,
 ) -> (ImplSubject<'tcx>, impl Iterator<Item = PredicateObligation<'tcx>>) {
-    let subject = selcx.tcx().impl_subject(impl_def_id);
+    let subject = selcx.tcx().bound_impl_subject(impl_def_id);
-    let subject = EarlyBinder(subject).subst(selcx.tcx(), impl_substs);
+    let subject = subject.subst(selcx.tcx(), impl_substs);
     let Normalized { value: subject, obligations: normalization_obligations1 } =
         super::normalize(selcx, param_env, ObligationCause::dummy(), subject);
 

compiler/rustc_ty_utils/src/ty.rs

@@ -2,9 +2,7 @@ use rustc_data_structures::fx::FxIndexSet;
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_middle::ty::subst::Subst;
-use rustc_middle::ty::{
+use rustc_middle::ty::{self, Binder, Predicate, PredicateKind, ToPredicate, Ty, TyCtxt};
-    self, Binder, EarlyBinder, Predicate, PredicateKind, ToPredicate, Ty, TyCtxt,
-};
 use rustc_trait_selection::traits;
 
 fn sized_constraint_for_ty<'tcx>(