Rollup merge of #145009 - jackh726:ra-next-solver-changes, r=compiler-errors

A couple small changes for rust-analyzer next-solver work

Originally written by `@flodiebold`

Author: Zalathar

compiler/rustc_middle/src/ty/predicate.rs

@@ -6,8 +6,7 @@ use rustc_macros::{HashStable, extension};
 use rustc_type_ir as ir;
 
 use crate::ty::{
-    self, DebruijnIndex, EarlyBinder, PredicatePolarity, Ty, TyCtxt, TypeFlags, Upcast, UpcastFrom,
-    WithCachedTypeInfo,
+    self, DebruijnIndex, EarlyBinder, Ty, TyCtxt, TypeFlags, Upcast, UpcastFrom, WithCachedTypeInfo,
 };
 
 pub type TraitRef<'tcx> = ir::TraitRef<TyCtxt<'tcx>>;
@@ -536,15 +535,6 @@ impl<'tcx> UpcastFrom<TyCtxt<'tcx>, ty::Binder<'tcx, TraitRef<'tcx>>> for Clause
     }
 }
 
-impl<'tcx> UpcastFrom<TyCtxt<'tcx>, ty::Binder<'tcx, TraitRef<'tcx>>> for PolyTraitPredicate<'tcx> {
-    fn upcast_from(from: ty::Binder<'tcx, TraitRef<'tcx>>, _tcx: TyCtxt<'tcx>) -> Self {
-        from.map_bound(|trait_ref| TraitPredicate {
-            trait_ref,
-            polarity: PredicatePolarity::Positive,
-        })
-    }
-}
-
 impl<'tcx> UpcastFrom<TyCtxt<'tcx>, TraitPredicate<'tcx>> for Predicate<'tcx> {
     fn upcast_from(from: TraitPredicate<'tcx>, tcx: TyCtxt<'tcx>) -> Self {
         PredicateKind::Clause(ClauseKind::Trait(from)).upcast(tcx)

compiler/rustc_type_ir/src/const_kind.rs

@@ -7,7 +7,10 @@ use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_macros::{Decodable_NoContext, Encodable_NoContext, HashStable_NoContext};
 use rustc_type_ir_macros::{Lift_Generic, TypeFoldable_Generic, TypeVisitable_Generic};
 
-use crate::{self as ty, DebruijnIndex, Interner};
+use crate::{
+    self as ty, DebruijnIndex, FallibleTypeFolder, Interner, TypeFoldable, TypeFolder,
+    TypeVisitable, TypeVisitor, VisitorResult,
+};
 
 /// Represents a constant in Rust.
 #[derive_where(Clone, Copy, Hash, PartialEq, Eq; I: Interner)]
@@ -120,3 +123,19 @@ impl<CTX> HashStable<CTX> for InferConst {
         }
     }
 }
+
+impl<I: Interner> TypeFoldable<I> for InferConst {
+    fn try_fold_with<F: FallibleTypeFolder<I>>(self, _folder: &mut F) -> Result<Self, F::Error> {
+        Ok(self)
+    }
+
+    fn fold_with<F: TypeFolder<I>>(self, _folder: &mut F) -> Self {
+        self
+    }
+}
+
+impl<I: Interner> TypeVisitable<I> for InferConst {
+    fn visit_with<V: TypeVisitor<I>>(&self, _visitor: &mut V) -> V::Result {
+        V::Result::output()
+    }
+}

compiler/rustc_type_ir/src/predicate.rs

@@ -184,6 +184,15 @@ impl<I: Interner> UpcastFrom<I, TraitRef<I>> for TraitPredicate<I> {
     }
 }
 
+impl<I: Interner> UpcastFrom<I, ty::Binder<I, TraitRef<I>>> for ty::Binder<I, TraitPredicate<I>> {
+    fn upcast_from(from: ty::Binder<I, TraitRef<I>>, _tcx: I) -> Self {
+        from.map_bound(|trait_ref| TraitPredicate {
+            trait_ref,
+            polarity: PredicatePolarity::Positive,
+        })
+    }
+}
+
 impl<I: Interner> fmt::Debug for TraitPredicate<I> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "TraitPredicate({:?}, polarity:{:?})", self.trait_ref, self.polarity)