Rollup merge of #110556 - kylematsuda:earlybinder-explicit-item-bounds, r=compiler-errors

Switch to `EarlyBinder` for `explicit_item_bounds`

Part of the work to finish https://github.com/rust-lang/rust/issues/105779.

This PR adds `EarlyBinder` to the return type of the `explicit_item_bounds` query and removes `bound_explicit_item_bounds`.

r? `@compiler-errors` (hope it's okay to request you, since you reviewed #110299 and #110498 😃)

compiler/rustc_middle/src/query/mod.rs

@@ -251,7 +251,7 @@ rustc_queries! {
     /// `key` is the `DefId` of the associated type or opaque type.
     ///
     /// Bounds from the parent (e.g. with nested impl trait) are not included.
-    query explicit_item_bounds(key: DefId) -> &'tcx [(ty::Predicate<'tcx>, Span)] {
+    query explicit_item_bounds(key: DefId) -> ty::EarlyBinder<&'tcx [(ty::Predicate<'tcx>, Span)]> {
         desc { |tcx| "finding item bounds for `{}`", tcx.def_path_str(key) }
         cache_on_disk_if { key.is_local() }
         separate_provide_extern

compiler/rustc_middle/src/ty/context.rs

@@ -1603,7 +1603,7 @@ impl<'tcx> TyCtxt<'tcx> {
         let ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. }) = ty.kind() else { return false };
         let future_trait = self.require_lang_item(LangItem::Future, None);
 
-        self.explicit_item_bounds(def_id).iter().any(|(predicate, _)| {
+        self.explicit_item_bounds(def_id).skip_binder().iter().any(|&(predicate, _)| {
             let ty::PredicateKind::Clause(ty::Clause::Trait(trait_predicate)) = predicate.kind().skip_binder() else {
                 return false;
             };

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -914,7 +914,7 @@ pub trait PrettyPrinter<'tcx>:
 
         // Grab the "TraitA + TraitB" from `impl TraitA + TraitB`,
         // by looking up the projections associated with the def_id.
-        let bounds = tcx.bound_explicit_item_bounds(def_id);
+        let bounds = tcx.explicit_item_bounds(def_id);
 
         let mut traits = FxIndexMap::default();
         let mut fn_traits = FxIndexMap::default();

compiler/rustc_middle/src/ty/subst.rs

@@ -612,6 +612,12 @@ where
     ) -> SubstIter<'s, 'tcx, I> {
         SubstIter { it: self.0.into_iter(), tcx, substs }
     }
+
+    /// Similar to [`subst_identity`](EarlyBinder::subst_identity),
+    /// but on an iterator of `TypeFoldable` values.
+    pub fn subst_identity_iter(self) -> I::IntoIter {
+        self.0.into_iter()
+    }
 }
 
 pub struct SubstIter<'s, 'tcx, I: IntoIterator> {
@@ -664,6 +670,12 @@ where
     ) -> SubstIterCopied<'s, 'tcx, I> {
         SubstIterCopied { it: self.0.into_iter(), tcx, substs }
     }
+
+    /// Similar to [`subst_identity`](EarlyBinder::subst_identity),
+    /// but on an iterator of values that deref to a `TypeFoldable`.
+    pub fn subst_identity_iter_copied(self) -> impl Iterator<Item = <I::Item as Deref>::Target> {
+        self.0.into_iter().map(|v| *v)
+    }
 }
 
 pub struct SubstIterCopied<'a, 'tcx, I: IntoIterator> {

compiler/rustc_middle/src/ty/util.rs

@@ -701,13 +701,6 @@ impl<'tcx> TyCtxt<'tcx> {
         if visitor.found_recursion { Err(expanded_type) } else { Ok(expanded_type) }
     }
 
-    pub fn bound_explicit_item_bounds(
-        self,
-        def_id: DefId,
-    ) -> ty::EarlyBinder<&'tcx [(ty::Predicate<'tcx>, rustc_span::Span)]> {
-        ty::EarlyBinder(self.explicit_item_bounds(def_id))
-    }
-
     /// Returns names of captured upvars for closures and generators.
     ///
     /// Here are some examples: