Rollup merge of #106970 - kylematsuda:earlybinder-item-bounds, r=lcnr

Switch to `EarlyBinder` for `item_bounds` query

Part of the work to finish #105779 (also see rust-lang/types-team#78).

Several queries `X` have a `bound_X` variant that wraps the output in `EarlyBinder`. This adds `EarlyBinder` to the return type of the `item_bounds` query and removes `bound_item_bounds`.

r? `@lcnr`

Author: matthiaskrgr

compiler/rustc_hir_analysis/src/collect/item_bounds.rs

@@ -99,12 +99,16 @@ pub(super) fn explicit_item_bounds(
     }
 }
 
-pub(super) fn item_bounds(tcx: TyCtxt<'_>, def_id: DefId) -> &'_ ty::List<ty::Predicate<'_>> {
-    tcx.mk_predicates(
+pub(super) fn item_bounds(
+    tcx: TyCtxt<'_>,
+    def_id: DefId,
+) -> ty::EarlyBinder<&'_ ty::List<ty::Predicate<'_>>> {
+    let bounds = tcx.mk_predicates(
         util::elaborate_predicates(
             tcx,
             tcx.explicit_item_bounds(def_id).iter().map(|&(bound, _span)| bound),
         )
         .map(|obligation| obligation.predicate),
-    )
+    );
+    ty::EarlyBinder(bounds)
 }

compiler/rustc_infer/src/infer/outlives/verify.rs

@@ -298,7 +298,7 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
         substs: SubstsRef<'tcx>,
     ) -> impl Iterator<Item = ty::Region<'tcx>> {
         let tcx = self.tcx;
-        let bounds = tcx.bound_item_bounds(def_id);
+        let bounds = tcx.item_bounds(def_id);
         trace!("{:#?}", bounds.0);
         bounds
             .subst_iter(tcx, substs)

compiler/rustc_middle/src/query/mod.rs

@@ -272,7 +272,7 @@ rustc_queries! {
     /// ```
     ///
     /// Bounds from the parent (e.g. with nested impl trait) are not included.
-    query item_bounds(key: DefId) -> &'tcx ty::List<ty::Predicate<'tcx>> {
+    query item_bounds(key: DefId) -> ty::EarlyBinder<&'tcx ty::List<ty::Predicate<'tcx>>> {
         desc { |tcx| "elaborating item bounds for `{}`", tcx.def_path_str(key) }
     }
 

compiler/rustc_middle/src/ty/util.rs

@@ -659,13 +659,6 @@ impl<'tcx> TyCtxt<'tcx> {
         ty::EarlyBinder(self.explicit_item_bounds(def_id))
     }
 
-    pub fn bound_item_bounds(
-        self,
-        def_id: DefId,
-    ) -> ty::EarlyBinder<&'tcx ty::List<ty::Predicate<'tcx>>> {
-        ty::EarlyBinder(self.item_bounds(def_id))
-    }
-
     pub fn bound_impl_subject(self, def_id: DefId) -> ty::EarlyBinder<ty::ImplSubject<'tcx>> {
         ty::EarlyBinder(self.impl_subject(def_id))
     }

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -1123,7 +1123,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     Some((DefIdOrName::DefId(def_id), fn_sig.output(), fn_sig.inputs().map_bound(|inputs| &inputs[1..])))
                 }
                 ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => {
-                    self.tcx.bound_item_bounds(def_id).subst(self.tcx, substs).iter().find_map(|pred| {
+                    self.tcx.item_bounds(def_id).subst(self.tcx, substs).iter().find_map(|pred| {
                         if let ty::PredicateKind::Clause(ty::Clause::Projection(proj)) = pred.kind().skip_binder()
                         && Some(proj.projection_ty.def_id) == self.tcx.lang_items().fn_once_output()
                         // args tuple will always be substs[1]

compiler/rustc_trait_selection/src/traits/project.rs

@@ -1375,7 +1375,7 @@ fn assemble_candidates_from_trait_def<'cx, 'tcx>(
     // Check whether the self-type is itself a projection.
     // If so, extract what we know from the trait and try to come up with a good answer.
     let bounds = match *obligation.predicate.self_ty().kind() {
-        ty::Alias(_, ref data) => tcx.bound_item_bounds(data.def_id).subst(tcx, data.substs),
+        ty::Alias(_, ref data) => tcx.item_bounds(data.def_id).subst(tcx, data.substs),
         ty::Infer(ty::TyVar(_)) => {
             // If the self-type is an inference variable, then it MAY wind up
             // being a projected type, so induce an ambiguity.

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

@@ -160,8 +160,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             _ => bug!("projection candidate for unexpected type: {:?}", placeholder_self_ty),
         };
 
-        let candidate_predicate =
-            tcx.bound_item_bounds(def_id).map_bound(|i| i[idx]).subst(tcx, substs);
+        let candidate_predicate = tcx.item_bounds(def_id).map_bound(|i| i[idx]).subst(tcx, substs);
         let candidate = candidate_predicate
             .to_opt_poly_trait_pred()
             .expect("projection candidate is not a trait predicate")
@@ -510,7 +509,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             // This maybe belongs in wf, but that can't (doesn't) handle
             // higher-ranked things.
             // Prevent, e.g., `dyn Iterator<Item = str>`.
-            for bound in self.tcx().bound_item_bounds(assoc_type).transpose_iter() {
+            for bound in self.tcx().item_bounds(assoc_type).transpose_iter() {
                 let subst_bound =
                     if defs.count() == 0 {
                         bound.subst(tcx, trait_predicate.trait_ref.substs)

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

@@ -1604,7 +1604,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 );
             }
         };
-        let bounds = tcx.bound_item_bounds(def_id).subst(tcx, substs);
+        let bounds = tcx.item_bounds(def_id).subst(tcx, substs);
 
         // The bounds returned by `item_bounds` may contain duplicates after
         // normalization, so try to deduplicate when possible to avoid

src/tools/clippy/clippy_utils/src/ty.rs

@@ -647,8 +647,8 @@ pub fn ty_sig<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> Option<ExprFnSig<'t
             Some(ExprFnSig::Closure(decl, subs.as_closure().sig()))
         },
         ty::FnDef(id, subs) => Some(ExprFnSig::Sig(cx.tcx.bound_fn_sig(id).subst(cx.tcx, subs), Some(id))),
-        ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. }) => {
-            sig_from_bounds(cx, ty, cx.tcx.item_bounds(def_id), cx.tcx.opt_parent(def_id))
+        ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => {
+            sig_from_bounds(cx, ty, cx.tcx.item_bounds(def_id).subst(cx.tcx, substs), cx.tcx.opt_parent(def_id))
         },
         ty::FnPtr(sig) => Some(ExprFnSig::Sig(sig, None)),
         ty::Dynamic(bounds, _, _) => {