Remove unused TypeFoldable/TypeVisitable impls.

compiler/rustc_middle/src/hir/place.rs

@@ -66,7 +66,6 @@ pub struct Place<'tcx> {
 ///
 /// This is an HIR version of [`rustc_middle::mir::Place`].
 #[derive(Clone, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable)]
-#[derive(TypeFoldable, TypeVisitable)]
 pub struct PlaceWithHirId<'tcx> {
     /// `HirId` of the expression or pattern producing this value.
     pub hir_id: HirId,

compiler/rustc_middle/src/thir.rs

@@ -234,7 +234,6 @@ pub enum StmtKind<'tcx> {
 }
 
 #[derive(Clone, Debug, Copy, PartialEq, Eq, Hash, HashStable, TyEncodable, TyDecodable)]
-#[derive(TypeFoldable, TypeVisitable)]
 pub struct LocalVarId(pub hir::HirId);
 
 /// A THIR expression.

compiler/rustc_middle/src/traits/mod.rs

@@ -569,7 +569,7 @@ pub struct DerivedObligationCause<'tcx> {
     pub parent_code: InternedObligationCauseCode<'tcx>,
 }
 
-#[derive(Clone, Debug, TypeFoldable, TypeVisitable, Lift)]
+#[derive(Clone, Debug, TypeVisitable, Lift)]
 pub enum SelectionError<'tcx> {
     /// The trait is not implemented.
     Unimplemented,

compiler/rustc_middle/src/traits/select.rs

@@ -103,7 +103,7 @@ pub type EvaluationCache<'tcx> = Cache<
 /// required for associated types to work in default impls, as the bounds
 /// are visible both as projection bounds and as where-clauses from the
 /// parameter environment.
-#[derive(PartialEq, Eq, Debug, Clone, TypeFoldable, TypeVisitable)]
+#[derive(PartialEq, Eq, Debug, Clone, TypeVisitable)]
 pub enum SelectionCandidate<'tcx> {
     /// A builtin implementation for some specific traits, used in cases
     /// where we cannot rely an ordinary library implementations.

compiler/rustc_middle/src/traits/solve.rs

@@ -120,7 +120,7 @@ impl<'tcx> std::ops::Deref for ExternalConstraints<'tcx> {
 }
 
 /// Additional constraints returned on success.
-#[derive(Debug, PartialEq, Eq, Clone, Hash, Default, TypeFoldable, TypeVisitable)]
+#[derive(Debug, PartialEq, Eq, Clone, Hash, Default)]
 pub struct ExternalConstraintsData<'tcx> {
     // FIXME: implement this.
     pub region_constraints: QueryRegionConstraints<'tcx>,

compiler/rustc_middle/src/ty/error.rs

@@ -28,7 +28,7 @@ impl<T> ExpectedFound<T> {
 }
 
 // Data structures used in type unification
-#[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable, Lift, PartialEq, Eq)]
+#[derive(Copy, Clone, Debug, TypeVisitable, Lift, PartialEq, Eq)]
 #[rustc_pass_by_value]
 pub enum TypeError<'tcx> {
     Mismatch,

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

@@ -2690,7 +2690,7 @@ impl<'tcx> ty::PolyTraitPredicate<'tcx> {
     }
 }
 
-#[derive(Debug, Copy, Clone, TypeFoldable, TypeVisitable, Lift)]
+#[derive(Debug, Copy, Clone, Lift)]
 pub struct PrintClosureAsImpl<'tcx> {
     pub closure: ty::ClosureSubsts<'tcx>,
 }

compiler/rustc_middle/src/ty/structural_impls.rs

@@ -4,7 +4,6 @@
 //! to help with the tedium.
 
 use crate::mir::interpret;
-use crate::mir::ProjectionKind;
 use crate::ty::fold::{FallibleTypeFolder, TypeFoldable, TypeSuperFoldable};
 use crate::ty::print::{with_no_trimmed_paths, FmtPrinter, Printer};
 use crate::ty::visit::{TypeSuperVisitable, TypeVisitable, TypeVisitor};
@@ -373,16 +372,6 @@ impl<'a, 'tcx> Lift<'tcx> for ty::ParamEnv<'a> {
 ///////////////////////////////////////////////////////////////////////////
 // Traversal implementations.
 
-/// AdtDefs are basically the same as a DefId.
-impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for ty::AdtDef<'tcx> {
-    fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>(
-        self,
-        _folder: &mut F,
-    ) -> Result<Self, F::Error> {
-        Ok(self)
-    }
-}
-
 impl<'tcx> TypeVisitable<TyCtxt<'tcx>> for ty::AdtDef<'tcx> {
     fn visit_with<V: TypeVisitor<TyCtxt<'tcx>>>(
         &self,
@@ -445,15 +434,6 @@ impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for &'tcx ty::List<ty::Const<'tcx>> {
     }
 }
 
-impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for &'tcx ty::List<ProjectionKind> {
-    fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>(
-        self,
-        folder: &mut F,
-    ) -> Result<Self, F::Error> {
-        ty::util::fold_list(self, folder, |tcx, v| tcx.mk_projs(v))
-    }
-}
-
 impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for Ty<'tcx> {
     fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>(
         self,

compiler/rustc_middle/src/ty/sty.rs

@@ -631,7 +631,7 @@ impl<'tcx> UpvarSubsts<'tcx> {
 /// type of the constant. The reason that `R` is represented as an extra type parameter
 /// is the same reason that [`ClosureSubsts`] have `CS` and `U` as type parameters:
 /// inline const can reference lifetimes that are internal to the creating function.
-#[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable)]
+#[derive(Copy, Clone, Debug)]
 pub struct InlineConstSubsts<'tcx> {
     /// Generic parameters from the enclosing item,
     /// concatenated with the inferred type of the constant.