Some more EarlyBinder cleanups

compiler/rustc_middle/src/ty/generics.rs

@@ -85,10 +85,10 @@ impl GenericParamDef {
     ) -> Option<EarlyBinder<ty::GenericArg<'tcx>>> {
         match self.kind {
             GenericParamDefKind::Type { has_default, .. } if has_default => {
-                Some(EarlyBinder(tcx.type_of(self.def_id).into()))
+                Some(tcx.bound_type_of(self.def_id).map_bound(|t| t.into()))
             }
             GenericParamDefKind::Const { has_default } if has_default => {
-                Some(EarlyBinder(tcx.const_param_default(self.def_id).into()))
+                Some(tcx.bound_const_param_default(self.def_id).map_bound(|c| c.into()))
             }
             _ => None,
         }

compiler/rustc_middle/src/ty/sty.rs

@@ -932,6 +932,10 @@ impl<T> EarlyBinder<T> {
         let value = f(self.0)?;
         Ok(EarlyBinder(value))
     }
+
+    pub fn rebind<U>(&self, value: U) -> EarlyBinder<U> {
+        EarlyBinder(value)
+    }
 }
 
 impl<T> EarlyBinder<Option<T>> {

compiler/rustc_middle/src/ty/util.rs

@@ -676,6 +676,10 @@ impl<'tcx> TyCtxt<'tcx> {
     ) -> ty::EarlyBinder<&'tcx ty::List<ty::Predicate<'tcx>>> {
         ty::EarlyBinder(self.item_bounds(def_id))
     }
+
+    pub fn bound_const_param_default(self, def_id: DefId) -> ty::EarlyBinder<ty::Const<'tcx>> {
+        ty::EarlyBinder(self.const_param_default(def_id))
+    }
 }
 
 struct OpaqueTypeExpander<'tcx> {

compiler/rustc_mir_transform/src/shim.rs

@@ -537,13 +537,12 @@ fn build_call_shim<'tcx>(
     };
 
     let def_id = instance.def_id();
-    let sig = tcx.fn_sig(def_id);
-    let mut sig = tcx.erase_late_bound_regions(sig);
+    let sig = tcx.bound_fn_sig(def_id);
+    let sig = sig.map_bound(|sig| tcx.erase_late_bound_regions(sig));
 
     assert_eq!(sig_substs.is_some(), !instance.has_polymorphic_mir_body());
-    if let Some(sig_substs) = sig_substs {
-        sig = EarlyBinder(sig).subst(tcx, sig_substs);
-    }
+    let mut sig =
+        if let Some(sig_substs) = sig_substs { sig.subst(tcx, sig_substs) } else { sig.0 };
 
     if let CallKind::Indirect(fnty) = call_kind {
         // `sig` determines our local decls, and thus the callee type in the `Call` terminator. This

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

@@ -12,7 +12,7 @@ use rustc_index::bit_set::GrowableBitSet;
 use rustc_infer::infer::InferOk;
 use rustc_infer::infer::LateBoundRegionConversionTime::HigherRankedType;
 use rustc_middle::ty::subst::{GenericArg, GenericArgKind, InternalSubsts, Subst, SubstsRef};
-use rustc_middle::ty::{self, EarlyBinder, GenericParamDefKind, Ty, TyCtxt};
+use rustc_middle::ty::{self, GenericParamDefKind, Ty, TyCtxt};
 use rustc_middle::ty::{ToPolyTraitRef, ToPredicate};
 use rustc_span::def_id::DefId;
 
@@ -555,7 +555,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
                         let bound_vars = tcx.mk_bound_variable_kinds(bound_vars.into_iter());
                         let bound =
-                            EarlyBinder(bound.0.kind().skip_binder()).subst(tcx, assoc_ty_substs);
+                            bound.map_bound(|b| b.kind().skip_binder()).subst(tcx, assoc_ty_substs);
                         tcx.mk_predicate(ty::Binder::bind_with_vars(bound, bound_vars))
                     };
                 let normalized_bound = normalize_with_depth_to(

compiler/rustc_typeck/src/astconv/mod.rs

@@ -550,7 +550,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     GenericParamDefKind::Const { has_default } => {
                         let ty = tcx.at(self.span).type_of(param.def_id);
                         if !infer_args && has_default {
-                            EarlyBinder(tcx.const_param_default(param.def_id))
+                            tcx.bound_const_param_default(param.def_id)
                                 .subst(tcx, substs.unwrap())
                                 .into()
                         } else {

compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs

@@ -1426,7 +1426,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     }
                     GenericParamDefKind::Const { has_default } => {
                         if !infer_args && has_default {
-                            EarlyBinder(tcx.const_param_default(param.def_id))
+                            tcx.bound_const_param_default(param.def_id)
                                 .subst(tcx, substs.unwrap())
                                 .into()
                         } else {

compiler/rustc_typeck/src/check/method/probe.rs

@@ -21,9 +21,7 @@ use rustc_middle::middle::stability;
 use rustc_middle::ty::fast_reject::{simplify_type, TreatParams};
 use rustc_middle::ty::subst::{InternalSubsts, Subst, SubstsRef};
 use rustc_middle::ty::GenericParamDefKind;
-use rustc_middle::ty::{
-    self, EarlyBinder, ParamEnvAnd, ToPredicate, Ty, TyCtxt, TypeFoldable, TypeVisitable,
-};
+use rustc_middle::ty::{self, ParamEnvAnd, ToPredicate, Ty, TyCtxt, TypeFoldable, TypeVisitable};
 use rustc_session::lint;
 use rustc_span::def_id::LocalDefId;
 use rustc_span::lev_distance::{
@@ -713,7 +711,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
             }
 
             let (impl_ty, impl_substs) = self.impl_ty_and_substs(impl_def_id);
-            let impl_ty = EarlyBinder(impl_ty).subst(self.tcx, impl_substs);
+            let impl_ty = impl_ty.subst(self.tcx, impl_substs);
 
             debug!("impl_ty: {:?}", impl_ty);
 
@@ -1811,9 +1809,12 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
         self.erase_late_bound_regions(xform_fn_sig)
     }
 
-    /// Gets the type of an impl and generate substitutions with placeholders.
-    fn impl_ty_and_substs(&self, impl_def_id: DefId) -> (Ty<'tcx>, SubstsRef<'tcx>) {
-        (self.tcx.type_of(impl_def_id), self.fresh_item_substs(impl_def_id))
+    /// Gets the type of an impl and generate substitutions with inference vars.
+    fn impl_ty_and_substs(
+        &self,
+        impl_def_id: DefId,
+    ) -> (ty::EarlyBinder<Ty<'tcx>>, SubstsRef<'tcx>) {
+        (self.tcx.bound_type_of(impl_def_id), self.fresh_item_substs(impl_def_id))
     }
 
     fn fresh_item_substs(&self, def_id: DefId) -> SubstsRef<'tcx> {

compiler/rustc_typeck/src/outlives/explicit.rs

@@ -6,19 +6,19 @@ use super::utils::*;
 
 #[derive(Debug)]
 pub struct ExplicitPredicatesMap<'tcx> {
-    map: FxHashMap<DefId, RequiredPredicates<'tcx>>,
+    map: FxHashMap<DefId, ty::EarlyBinder<RequiredPredicates<'tcx>>>,
 }
 
 impl<'tcx> ExplicitPredicatesMap<'tcx> {
     pub fn new() -> ExplicitPredicatesMap<'tcx> {
         ExplicitPredicatesMap { map: FxHashMap::default() }
     }
 
-    pub fn explicit_predicates_of(
+    pub(crate) fn explicit_predicates_of(
         &mut self,
         tcx: TyCtxt<'tcx>,
         def_id: DefId,
-    ) -> &RequiredPredicates<'tcx> {
+    ) -> &ty::EarlyBinder<RequiredPredicates<'tcx>> {
         self.map.entry(def_id).or_insert_with(|| {
             let predicates = if def_id.is_local() {
                 tcx.explicit_predicates_of(def_id)
@@ -63,7 +63,7 @@ impl<'tcx> ExplicitPredicatesMap<'tcx> {
                 }
             }
 
-            required_predicates
+            ty::EarlyBinder(required_predicates)
         })
     }
 }

compiler/rustc_typeck/src/outlives/implicit_infer.rs

@@ -2,7 +2,7 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::DefId;
 use rustc_middle::ty::subst::{GenericArg, GenericArgKind, Subst};
-use rustc_middle::ty::{self, EarlyBinder, Ty, TyCtxt};
+use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_span::Span;
 
 use super::explicit::ExplicitPredicatesMap;
@@ -13,20 +13,19 @@ use super::utils::*;
 /// `global_inferred_outlives`: this is initially the empty map that
 ///     was generated by walking the items in the crate. This will
 ///     now be filled with inferred predicates.
-pub fn infer_predicates<'tcx>(
+pub(super) fn infer_predicates<'tcx>(
     tcx: TyCtxt<'tcx>,
-    explicit_map: &mut ExplicitPredicatesMap<'tcx>,
-) -> FxHashMap<DefId, RequiredPredicates<'tcx>> {
+) -> FxHashMap<DefId, ty::EarlyBinder<RequiredPredicates<'tcx>>> {
     debug!("infer_predicates");
 
-    let mut predicates_added = true;
+    let mut explicit_map = ExplicitPredicatesMap::new();
 
     let mut global_inferred_outlives = FxHashMap::default();
 
     // If new predicates were added then we need to re-calculate
     // all crates since there could be new implied predicates.
-    while predicates_added {
-        predicates_added = false;
+    'outer: loop {
+        let mut predicates_added = false;
 
         // Visit all the crates and infer predicates
         for id in tcx.hir().items() {
@@ -53,9 +52,9 @@ pub fn infer_predicates<'tcx>(
                             tcx,
                             field_ty,
                             field_span,
-                            &mut global_inferred_outlives,
+                            &global_inferred_outlives,
                             &mut item_required_predicates,
-                            explicit_map,
+                            &mut explicit_map,
                         );
                     }
                 }
@@ -70,12 +69,17 @@ pub fn infer_predicates<'tcx>(
             // we walk the crates again and re-calculate predicates for all
             // items.
             let item_predicates_len: usize =
-                global_inferred_outlives.get(&item_did.to_def_id()).map_or(0, |p| p.len());
+                global_inferred_outlives.get(&item_did.to_def_id()).map_or(0, |p| p.0.len());
             if item_required_predicates.len() > item_predicates_len {
                 predicates_added = true;
-                global_inferred_outlives.insert(item_did.to_def_id(), item_required_predicates);
+                global_inferred_outlives
+                    .insert(item_did.to_def_id(), ty::EarlyBinder(item_required_predicates));
             }
         }
+
+        if !predicates_added {
+            break 'outer;
+        }
     }
 
     global_inferred_outlives
@@ -85,7 +89,7 @@ fn insert_required_predicates_to_be_wf<'tcx>(
     tcx: TyCtxt<'tcx>,
     field_ty: Ty<'tcx>,
     field_span: Span,
-    global_inferred_outlives: &FxHashMap<DefId, RequiredPredicates<'tcx>>,
+    global_inferred_outlives: &FxHashMap<DefId, ty::EarlyBinder<RequiredPredicates<'tcx>>>,
     required_predicates: &mut RequiredPredicates<'tcx>,
     explicit_map: &mut ExplicitPredicatesMap<'tcx>,
 ) {
@@ -133,11 +137,13 @@ fn insert_required_predicates_to_be_wf<'tcx>(
                 // 'a` holds for `Foo`.
                 debug!("Adt");
                 if let Some(unsubstituted_predicates) = global_inferred_outlives.get(&def.did()) {
-                    for (unsubstituted_predicate, &span) in unsubstituted_predicates {
+                    for (unsubstituted_predicate, &span) in &unsubstituted_predicates.0 {
                         // `unsubstituted_predicate` is `U: 'b` in the
                         // example above.  So apply the substitution to
                         // get `T: 'a` (or `predicate`):
-                        let predicate = EarlyBinder(*unsubstituted_predicate).subst(tcx, substs);
+                        let predicate = unsubstituted_predicates
+                            .rebind(*unsubstituted_predicate)
+                            .subst(tcx, substs);
                         insert_outlives_predicate(
                             tcx,
                             predicate.0,
@@ -224,7 +230,7 @@ fn insert_required_predicates_to_be_wf<'tcx>(
 /// will give us `U: 'static` and `U: Foo`. The latter we
 /// can ignore, but we will want to process `U: 'static`,
 /// applying the substitution as above.
-pub fn check_explicit_predicates<'tcx>(
+fn check_explicit_predicates<'tcx>(
     tcx: TyCtxt<'tcx>,
     def_id: DefId,
     substs: &[GenericArg<'tcx>],
@@ -242,7 +248,7 @@ pub fn check_explicit_predicates<'tcx>(
     );
     let explicit_predicates = explicit_map.explicit_predicates_of(tcx, def_id);
 
-    for (outlives_predicate, &span) in explicit_predicates {
+    for (outlives_predicate, &span) in &explicit_predicates.0 {
         debug!("outlives_predicate = {:?}", &outlives_predicate);
 
         // Careful: If we are inferring the effects of a `dyn Trait<..>`
@@ -287,7 +293,7 @@ pub fn check_explicit_predicates<'tcx>(
             continue;
         }
 
-        let predicate = EarlyBinder(*outlives_predicate).subst(tcx, substs);
+        let predicate = explicit_predicates.rebind(*outlives_predicate).subst(tcx, substs);
         debug!("predicate = {:?}", &predicate);
         insert_outlives_predicate(tcx, predicate.0, predicate.1, span, required_predicates);
     }

compiler/rustc_typeck/src/outlives/mod.rs

@@ -88,9 +88,7 @@ fn inferred_outlives_crate(tcx: TyCtxt<'_>, (): ()) -> CratePredicatesMap<'_> {
     // for the type.
 
     // Compute the inferred predicates
-    let mut exp_map = explicit::ExplicitPredicatesMap::new();
-
-    let global_inferred_outlives = implicit_infer::infer_predicates(tcx, &mut exp_map);
+    let global_inferred_outlives = implicit_infer::infer_predicates(tcx);
 
     // Convert the inferred predicates into the "collected" form the
     // global data structure expects.
@@ -100,7 +98,7 @@ fn inferred_outlives_crate(tcx: TyCtxt<'_>, (): ()) -> CratePredicatesMap<'_> {
     let predicates = global_inferred_outlives
         .iter()
         .map(|(&def_id, set)| {
-            let predicates = &*tcx.arena.alloc_from_iter(set.iter().filter_map(
+            let predicates = &*tcx.arena.alloc_from_iter(set.0.iter().filter_map(
                 |(ty::OutlivesPredicate(kind1, region2), &span)| {
                     match kind1.unpack() {
                         GenericArgKind::Type(ty1) => Some((

compiler/rustc_typeck/src/outlives/utils.rs

@@ -7,12 +7,12 @@ use std::collections::BTreeMap;
 
 /// Tracks the `T: 'a` or `'a: 'a` predicates that we have inferred
 /// must be added to the struct header.
-pub type RequiredPredicates<'tcx> =
+pub(crate) type RequiredPredicates<'tcx> =
     BTreeMap<ty::OutlivesPredicate<GenericArg<'tcx>, ty::Region<'tcx>>, Span>;
 
 /// Given a requirement `T: 'a` or `'b: 'a`, deduce the
 /// outlives_component and add it to `required_predicates`
-pub fn insert_outlives_predicate<'tcx>(
+pub(crate) fn insert_outlives_predicate<'tcx>(
     tcx: TyCtxt<'tcx>,
     kind: GenericArg<'tcx>,
     outlived_region: Region<'tcx>,