Remove unused Lift derives.

I found these by commenting out all `Lift` derives and then adding back
the ones that were necessary to successfully compile.

Author: nnethercote

Diff for: compiler/rustc_middle/src/infer/canonical.rs

@@ -34,7 +34,7 @@ use std::ops::Index;
 /// variables have been rewritten to "canonical vars". These are
 /// numbered starting from 0 in order of first appearance.
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TyDecodable, TyEncodable)]
-#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
+#[derive(HashStable, TypeFoldable, TypeVisitable)]
 pub struct Canonical<'tcx, V> {
     pub value: V,
     pub max_universe: ty::UniverseIndex,
@@ -72,7 +72,7 @@ impl<'tcx> ty::TypeFoldable<TyCtxt<'tcx>> for CanonicalVarInfos<'tcx> {
 /// variables. You will need to supply it later to instantiate the
 /// canonicalized query response.
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TyDecodable, TyEncodable)]
-#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
+#[derive(HashStable, TypeFoldable, TypeVisitable)]
 pub struct CanonicalVarValues<'tcx> {
     pub var_values: ty::GenericArgsRef<'tcx>,
 }
@@ -311,7 +311,7 @@ pub enum CanonicalTyVarKind {
 /// After we execute a query with a canonicalized key, we get back a
 /// `Canonical<QueryResponse<..>>`. You can use
 /// `instantiate_query_result` to access the data in this result.
-#[derive(Clone, Debug, HashStable, TypeFoldable, TypeVisitable, Lift)]
+#[derive(Clone, Debug, HashStable, TypeFoldable, TypeVisitable)]
 pub struct QueryResponse<'tcx, R> {
     pub var_values: CanonicalVarValues<'tcx>,
     pub region_constraints: QueryRegionConstraints<'tcx>,
@@ -326,7 +326,7 @@ pub struct QueryResponse<'tcx, R> {
 }
 
 #[derive(Clone, Debug, Default, PartialEq, Eq, Hash)]
-#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
+#[derive(HashStable, TypeFoldable, TypeVisitable)]
 pub struct QueryRegionConstraints<'tcx> {
     pub outlives: Vec<QueryOutlivesConstraint<'tcx>>,
     pub member_constraints: Vec<MemberConstraint<'tcx>>,

Diff for: compiler/rustc_middle/src/infer/mod.rs

@@ -13,7 +13,7 @@ use rustc_span::Span;
 /// R0 member of [O1..On]
 /// ```
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
-#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
+#[derive(HashStable, TypeFoldable, TypeVisitable)]
 pub struct MemberConstraint<'tcx> {
     /// The `DefId` and args of the opaque type causing this constraint.
     /// Used for error reporting.

Diff for: compiler/rustc_middle/src/mir/interpret/mod.rs

@@ -162,7 +162,7 @@ pub use self::pointer::{Pointer, PointerArithmetic, Provenance};
 /// - A constant
 /// - A static
 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash, TyEncodable, TyDecodable)]
-#[derive(HashStable, Lift, TypeFoldable, TypeVisitable)]
+#[derive(HashStable, TypeFoldable, TypeVisitable)]
 pub struct GlobalId<'tcx> {
     /// For a constant or static, the `Instance` of the item itself.
     /// For a promoted global, the `Instance` of the function they belong to.

Diff for: compiler/rustc_middle/src/mir/mod.rs

@@ -2295,7 +2295,7 @@ pub struct Constant<'tcx> {
 }
 
 #[derive(Clone, Copy, PartialEq, Eq, TyEncodable, TyDecodable, Hash, HashStable, Debug)]
-#[derive(Lift, TypeFoldable, TypeVisitable)]
+#[derive(TypeFoldable, TypeVisitable)]
 pub enum ConstantKind<'tcx> {
     /// This constant came from the type system.
     ///
@@ -2615,7 +2615,7 @@ impl<'tcx> ConstantKind<'tcx> {
 }
 
 /// An unevaluated (potentially generic) constant used in MIR.
-#[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord, TyEncodable, TyDecodable, Lift)]
+#[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord, TyEncodable, TyDecodable)]
 #[derive(Hash, HashStable, TypeFoldable, TypeVisitable)]
 pub struct UnevaluatedConst<'tcx> {
     pub def: DefId,

Diff for: compiler/rustc_middle/src/mir/query.rs

@@ -334,7 +334,7 @@ rustc_data_structures::static_assert_size!(ConstraintCategory<'_>, 16);
 ///
 /// See also `rustc_const_eval::borrow_check::constraints`.
 #[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord, Hash)]
-#[derive(TyEncodable, TyDecodable, HashStable, Lift, TypeVisitable, TypeFoldable)]
+#[derive(TyEncodable, TyDecodable, HashStable, TypeVisitable, TypeFoldable)]
 pub enum ConstraintCategory<'tcx> {
     Return(ReturnConstraint),
     Yield,

Diff for: compiler/rustc_middle/src/traits/mod.rs

@@ -86,7 +86,7 @@ pub enum Reveal {
 ///
 /// We do not want to intern this as there are a lot of obligation causes which
 /// only live for a short period of time.
-#[derive(Clone, Debug, PartialEq, Eq, Lift, HashStable, TyEncodable, TyDecodable)]
+#[derive(Clone, Debug, PartialEq, Eq, HashStable, TyEncodable, TyDecodable)]
 #[derive(TypeVisitable, TypeFoldable)]
 pub struct ObligationCause<'tcx> {
     pub span: Span,
@@ -194,15 +194,15 @@ impl<'tcx> ObligationCause<'tcx> {
     }
 }
 
-#[derive(Clone, Debug, PartialEq, Eq, Lift, HashStable, TyEncodable, TyDecodable)]
+#[derive(Clone, Debug, PartialEq, Eq, HashStable, TyEncodable, TyDecodable)]
 #[derive(TypeVisitable, TypeFoldable)]
 pub struct UnifyReceiverContext<'tcx> {
     pub assoc_item: ty::AssocItem,
     pub param_env: ty::ParamEnv<'tcx>,
     pub args: GenericArgsRef<'tcx>,
 }
 
-#[derive(Clone, PartialEq, Eq, Lift, Default, HashStable)]
+#[derive(Clone, PartialEq, Eq, Default, HashStable)]
 #[derive(TypeVisitable, TypeFoldable, TyEncodable, TyDecodable)]
 pub struct InternedObligationCauseCode<'tcx> {
     /// `None` for `ObligationCauseCode::MiscObligation` (a common case, occurs ~60% of
@@ -238,7 +238,7 @@ impl<'tcx> std::ops::Deref for InternedObligationCauseCode<'tcx> {
     }
 }
 
-#[derive(Clone, Debug, PartialEq, Eq, Lift, HashStable, TyEncodable, TyDecodable)]
+#[derive(Clone, Debug, PartialEq, Eq, HashStable, TyEncodable, TyDecodable)]
 #[derive(TypeVisitable, TypeFoldable)]
 pub enum ObligationCauseCode<'tcx> {
     /// Not well classified or should be obvious from the span.
@@ -470,7 +470,7 @@ pub enum WellFormedLoc {
     },
 }
 
-#[derive(Clone, Debug, PartialEq, Eq, Lift, HashStable, TyEncodable, TyDecodable)]
+#[derive(Clone, Debug, PartialEq, Eq, HashStable, TyEncodable, TyDecodable)]
 #[derive(TypeVisitable, TypeFoldable)]
 pub struct ImplDerivedObligationCause<'tcx> {
     pub derived: DerivedObligationCause<'tcx>,
@@ -531,7 +531,7 @@ impl<'tcx> ty::Lift<'tcx> for StatementAsExpression {
     }
 }
 
-#[derive(Clone, Debug, PartialEq, Eq, Lift, HashStable, TyEncodable, TyDecodable)]
+#[derive(Clone, Debug, PartialEq, Eq, HashStable, TyEncodable, TyDecodable)]
 #[derive(TypeVisitable, TypeFoldable)]
 pub struct MatchExpressionArmCause<'tcx> {
     pub arm_block_id: Option<hir::HirId>,
@@ -547,7 +547,7 @@ pub struct MatchExpressionArmCause<'tcx> {
 }
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
-#[derive(Lift, TypeFoldable, TypeVisitable, HashStable, TyEncodable, TyDecodable)]
+#[derive(TypeFoldable, TypeVisitable, HashStable, TyEncodable, TyDecodable)]
 pub struct IfExpressionCause<'tcx> {
     pub then_id: hir::HirId,
     pub else_id: hir::HirId,
@@ -557,7 +557,7 @@ pub struct IfExpressionCause<'tcx> {
     pub opt_suggest_box_span: Option<Span>,
 }
 
-#[derive(Clone, Debug, PartialEq, Eq, Lift, HashStable, TyEncodable, TyDecodable)]
+#[derive(Clone, Debug, PartialEq, Eq, HashStable, TyEncodable, TyDecodable)]
 #[derive(TypeVisitable, TypeFoldable)]
 pub struct DerivedObligationCause<'tcx> {
     /// The trait predicate of the parent obligation that led to the
@@ -570,7 +570,7 @@ pub struct DerivedObligationCause<'tcx> {
     pub parent_code: InternedObligationCauseCode<'tcx>,
 }
 
-#[derive(Clone, Debug, TypeVisitable, Lift)]
+#[derive(Clone, Debug, TypeVisitable)]
 pub enum SelectionError<'tcx> {
     /// The trait is not implemented.
     Unimplemented,
@@ -593,7 +593,7 @@ pub enum SelectionError<'tcx> {
     OpaqueTypeAutoTraitLeakageUnknown(DefId),
 }
 
-#[derive(Clone, Debug, TypeVisitable, Lift)]
+#[derive(Clone, Debug, TypeVisitable)]
 pub struct SelectionOutputTypeParameterMismatch<'tcx> {
     pub found_trait_ref: ty::PolyTraitRef<'tcx>,
     pub expected_trait_ref: ty::PolyTraitRef<'tcx>,
@@ -638,7 +638,7 @@ pub type SelectionResult<'tcx, T> = Result<Option<T>, SelectionError<'tcx>>;
 /// ### The type parameter `N`
 ///
 /// See explanation on `ImplSourceUserDefinedData`.
-#[derive(Clone, PartialEq, Eq, TyEncodable, TyDecodable, HashStable, Lift)]
+#[derive(Clone, PartialEq, Eq, TyEncodable, TyDecodable, HashStable)]
 #[derive(TypeFoldable, TypeVisitable)]
 pub enum ImplSource<'tcx, N> {
     /// ImplSource identifying a particular impl.
@@ -704,7 +704,7 @@ impl<'tcx, N> ImplSource<'tcx, N> {
 /// is `Obligation`, as one might expect. During codegen, however, this
 /// is `()`, because codegen only requires a shallow resolution of an
 /// impl, and nested obligations are satisfied later.
-#[derive(Clone, PartialEq, Eq, TyEncodable, TyDecodable, HashStable, Lift)]
+#[derive(Clone, PartialEq, Eq, TyEncodable, TyDecodable, HashStable)]
 #[derive(TypeFoldable, TypeVisitable)]
 pub struct ImplSourceUserDefinedData<'tcx, N> {
     pub impl_def_id: DefId,

Diff for: compiler/rustc_middle/src/traits/query.rs

@@ -17,8 +17,7 @@ pub mod type_op {
     use crate::ty::{Predicate, Ty, TyCtxt, UserType};
     use std::fmt;
 
-    #[derive(Copy, Clone, Debug, Hash, PartialEq, Eq, HashStable, Lift)]
-    #[derive(TypeFoldable, TypeVisitable)]
+    #[derive(Copy, Clone, Debug, Hash, PartialEq, Eq, HashStable, TypeFoldable, TypeVisitable)]
     pub struct AscribeUserType<'tcx> {
         pub mir_ty: Ty<'tcx>,
         pub user_ty: UserType<'tcx>,
@@ -30,22 +29,19 @@ pub mod type_op {
         }
     }
 
-    #[derive(Copy, Clone, Debug, Hash, PartialEq, Eq, HashStable, Lift)]
-    #[derive(TypeFoldable, TypeVisitable)]
+    #[derive(Copy, Clone, Debug, Hash, PartialEq, Eq, HashStable, TypeFoldable, TypeVisitable)]
     pub struct Eq<'tcx> {
         pub a: Ty<'tcx>,
         pub b: Ty<'tcx>,
     }
 
-    #[derive(Copy, Clone, Debug, Hash, PartialEq, Eq, HashStable, Lift)]
-    #[derive(TypeFoldable, TypeVisitable)]
+    #[derive(Copy, Clone, Debug, Hash, PartialEq, Eq, HashStable, TypeFoldable, TypeVisitable)]
     pub struct Subtype<'tcx> {
         pub sub: Ty<'tcx>,
         pub sup: Ty<'tcx>,
     }
 
-    #[derive(Copy, Clone, Debug, Hash, PartialEq, Eq, HashStable, Lift)]
-    #[derive(TypeFoldable, TypeVisitable)]
+    #[derive(Copy, Clone, Debug, Hash, PartialEq, Eq, HashStable, TypeFoldable, TypeVisitable)]
     pub struct ProvePredicate<'tcx> {
         pub predicate: Predicate<'tcx>,
     }
@@ -56,8 +52,7 @@ pub mod type_op {
         }
     }
 
-    #[derive(Copy, Clone, Debug, Hash, PartialEq, Eq, HashStable, Lift)]
-    #[derive(TypeFoldable, TypeVisitable)]
+    #[derive(Copy, Clone, Debug, Hash, PartialEq, Eq, HashStable, TypeFoldable, TypeVisitable)]
     pub struct Normalize<T> {
         pub value: T,
     }
@@ -101,7 +96,7 @@ impl<'tcx> From<TypeError<'tcx>> for NoSolution {
     }
 }
 
-#[derive(Clone, Debug, Default, HashStable, TypeFoldable, TypeVisitable, Lift)]
+#[derive(Clone, Debug, Default, HashStable, TypeFoldable, TypeVisitable)]
 pub struct DropckOutlivesResult<'tcx> {
     pub kinds: Vec<GenericArg<'tcx>>,
     pub overflows: Vec<Ty<'tcx>>,
@@ -194,7 +189,7 @@ pub struct MethodAutoderefBadTy<'tcx> {
 }
 
 /// Result from the `normalize_projection_ty` query.
-#[derive(Clone, Debug, HashStable, TypeFoldable, TypeVisitable, Lift)]
+#[derive(Clone, Debug, HashStable, TypeFoldable, TypeVisitable)]
 pub struct NormalizationResult<'tcx> {
     /// Result of normalization.
     pub normalized_ty: Ty<'tcx>,
@@ -207,7 +202,7 @@ pub struct NormalizationResult<'tcx> {
 /// case they are called implied bounds). They are fed to the
 /// `OutlivesEnv` which in turn is supplied to the region checker and
 /// other parts of the inference system.
-#[derive(Clone, Debug, TypeFoldable, TypeVisitable, Lift, HashStable)]
+#[derive(Clone, Debug, TypeFoldable, TypeVisitable, HashStable)]
 pub enum OutlivesBound<'tcx> {
     RegionSubRegion(ty::Region<'tcx>, ty::Region<'tcx>),
     RegionSubParam(ty::Region<'tcx>, ty::ParamTy),

Diff for: compiler/rustc_middle/src/ty/adjustment.rs

@@ -76,7 +76,7 @@ pub enum PointerCoercion {
 ///    At some point, of course, `Box` should move out of the compiler, in which
 ///    case this is analogous to transforming a struct. E.g., `Box<[i32; 4]>` ->
 ///    `Box<[i32]>` is an `Adjust::Unsize` with the target `Box<[i32]>`.
-#[derive(Clone, TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable, Lift)]
+#[derive(Clone, TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable)]
 pub struct Adjustment<'tcx> {
     pub kind: Adjust<'tcx>,
     pub target: Ty<'tcx>,
@@ -88,7 +88,7 @@ impl<'tcx> Adjustment<'tcx> {
     }
 }
 
-#[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable, Lift)]
+#[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable)]
 pub enum Adjust<'tcx> {
     /// Go from ! to any type.
     NeverToAny,
@@ -110,7 +110,7 @@ pub enum Adjust<'tcx> {
 /// The target type is `U` in both cases, with the region and mutability
 /// being those shared by both the receiver and the returned reference.
 #[derive(Copy, Clone, PartialEq, Debug, TyEncodable, TyDecodable, HashStable)]
-#[derive(TypeFoldable, TypeVisitable, Lift)]
+#[derive(TypeFoldable, TypeVisitable)]
 pub struct OverloadedDeref<'tcx> {
     pub region: ty::Region<'tcx>,
     pub mutbl: hir::Mutability,
@@ -182,7 +182,7 @@ impl From<AutoBorrowMutability> for hir::Mutability {
 }
 
 #[derive(Copy, Clone, PartialEq, Debug, TyEncodable, TyDecodable, HashStable)]
-#[derive(TypeFoldable, TypeVisitable, Lift)]
+#[derive(TypeFoldable, TypeVisitable)]
 pub enum AutoBorrow<'tcx> {
     /// Converts from T to &T.
     Ref(ty::Region<'tcx>, AutoBorrowMutability),

Diff for: compiler/rustc_middle/src/ty/consts/kind.rs

@@ -8,7 +8,7 @@ use rustc_hir::def_id::DefId;
 use rustc_macros::HashStable;
 
 /// An unevaluated (potentially generic) constant used in the type-system.
-#[derive(Copy, Clone, Eq, PartialEq, PartialOrd, Ord, TyEncodable, TyDecodable, Lift)]
+#[derive(Copy, Clone, Eq, PartialEq, PartialOrd, Ord, TyEncodable, TyDecodable)]
 #[derive(Hash, HashStable, TypeFoldable, TypeVisitable)]
 pub struct UnevaluatedConst<'tcx> {
     pub def: DefId,

Diff for: compiler/rustc_middle/src/ty/error.rs

@@ -11,7 +11,7 @@ use std::collections::hash_map::DefaultHasher;
 use std::hash::{Hash, Hasher};
 use std::path::PathBuf;
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq, TypeFoldable, TypeVisitable, Lift)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, TypeFoldable, TypeVisitable)]
 pub struct ExpectedFound<T> {
     pub expected: T,
     pub found: T,
@@ -28,7 +28,7 @@ impl<T> ExpectedFound<T> {
 }
 
 // Data structures used in type unification
-#[derive(Copy, Clone, Debug, TypeVisitable, Lift, PartialEq, Eq)]
+#[derive(Copy, Clone, Debug, TypeVisitable, PartialEq, Eq)]
 #[rustc_pass_by_value]
 pub enum TypeError<'tcx> {
     Mismatch,

Diff for: compiler/rustc_middle/src/ty/generic_args.rs

@@ -1029,7 +1029,7 @@ impl<'a, 'tcx> ArgFolder<'a, 'tcx> {
 /// Stores the user-given args to reach some fully qualified path
 /// (e.g., `<T>::Item` or `<T as Trait>::Item`).
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
-#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
+#[derive(HashStable, TypeFoldable, TypeVisitable)]
 pub struct UserArgs<'tcx> {
     /// The args for the item as given by the user.
     pub args: GenericArgsRef<'tcx>,
@@ -1056,7 +1056,7 @@ pub struct UserArgs<'tcx> {
 /// the self type, giving `Foo<?A>`. Finally, we unify that with
 /// the self type here, which contains `?A` to be `&'static u32`
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
-#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
+#[derive(HashStable, TypeFoldable, TypeVisitable)]
 pub struct UserSelfTy<'tcx> {
     pub impl_def_id: DefId,
     pub self_ty: Ty<'tcx>,

Diff for: compiler/rustc_middle/src/ty/instance.rs

@@ -18,6 +18,9 @@ use std::fmt;
 /// Monomorphization happens on-the-fly and no monomorphized MIR is ever created. Instead, this type
 /// simply couples a potentially generic `InstanceDef` with some args, and codegen and const eval
 /// will do all required substitution as they run.
+///
+/// Note: the `Lift` impl is currently not used by rustc, but is used by
+/// rustc_codegen_cranelift when the `jit` feature is enabled.
 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, TyEncodable, TyDecodable)]
 #[derive(HashStable, Lift, TypeFoldable, TypeVisitable)]
 pub struct Instance<'tcx> {

Diff for: compiler/rustc_middle/src/ty/mod.rs

@@ -1510,7 +1510,7 @@ impl<'a, 'tcx> IntoIterator for &'a InstantiatedPredicates<'tcx> {
     }
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable, TyEncodable, TyDecodable, Lift)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable, TyEncodable, TyDecodable)]
 #[derive(TypeFoldable, TypeVisitable)]
 pub struct OpaqueTypeKey<'tcx> {
     pub def_id: LocalDefId,
@@ -1793,7 +1793,7 @@ impl<'tcx> ParamEnv<'tcx> {
 }
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable)]
-#[derive(HashStable, Lift)]
+#[derive(HashStable)]
 pub struct ParamEnvAnd<'tcx, T> {
     pub param_env: ParamEnv<'tcx>,
     pub value: T,

Diff for: compiler/rustc_middle/src/ty/sty.rs

@@ -351,7 +351,7 @@ impl<'tcx> ClosureArgs<'tcx> {
 }
 
 /// Similar to `ClosureArgs`; see the above documentation for more.
-#[derive(Copy, Clone, PartialEq, Eq, Debug, TypeFoldable, TypeVisitable, Lift)]
+#[derive(Copy, Clone, PartialEq, Eq, Debug, TypeFoldable, TypeVisitable)]
 pub struct GeneratorArgs<'tcx> {
     pub args: GenericArgsRef<'tcx>,
 }
@@ -1305,7 +1305,7 @@ impl<'tcx> AliasTy<'tcx> {
     }
 }
 
-#[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable, Lift)]
+#[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable)]
 pub struct GenSig<'tcx> {
     pub resume_ty: Ty<'tcx>,
     pub yield_ty: Ty<'tcx>,