Remove unnecessary lift calls

src/librustc/infer/canonical/canonicalizer.rs

@@ -14,7 +14,7 @@ use crate::mir::interpret::ConstValue;
 use std::sync::atomic::Ordering;
 use crate::ty::fold::{TypeFoldable, TypeFolder};
 use crate::ty::subst::Kind;
-use crate::ty::{self, BoundVar, InferConst, Lift, List, Ty, TyCtxt, TypeFlags};
+use crate::ty::{self, BoundVar, InferConst, List, Ty, TyCtxt, TypeFlags};
 use crate::ty::flags::FlagComputation;
 
 use rustc_data_structures::fx::FxHashMap;
@@ -43,7 +43,7 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
         query_state: &mut OriginalQueryValues<'tcx>,
     ) -> Canonicalized<'tcx, V>
     where
-        V: TypeFoldable<'tcx> + Lift<'tcx>,
+        V: TypeFoldable<'tcx>,
     {
         self.tcx
             .sess
@@ -87,7 +87,7 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
     /// [c]: https://rust-lang.github.io/rustc-guide/traits/canonicalization.html#canonicalizing-the-query-result
     pub fn canonicalize_response<V>(&self, value: &V) -> Canonicalized<'tcx, V>
     where
-        V: TypeFoldable<'tcx> + Lift<'tcx>,
+        V: TypeFoldable<'tcx>,
     {
         let mut query_state = OriginalQueryValues::default();
         Canonicalizer::canonicalize(
@@ -101,7 +101,7 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
 
     pub fn canonicalize_user_type_annotation<V>(&self, value: &V) -> Canonicalized<'tcx, V>
     where
-        V: TypeFoldable<'tcx> + Lift<'tcx>,
+        V: TypeFoldable<'tcx>,
     {
         let mut query_state = OriginalQueryValues::default();
         Canonicalizer::canonicalize(
@@ -132,7 +132,7 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
         query_state: &mut OriginalQueryValues<'tcx>,
     ) -> Canonicalized<'tcx, V>
     where
-        V: TypeFoldable<'tcx> + Lift<'tcx>,
+        V: TypeFoldable<'tcx>,
     {
         self.tcx
             .sess
@@ -506,7 +506,7 @@ impl<'cx, 'tcx> Canonicalizer<'cx, 'tcx> {
         query_state: &mut OriginalQueryValues<'tcx>,
     ) -> Canonicalized<'tcx, V>
     where
-        V: TypeFoldable<'tcx> + Lift<'tcx>,
+        V: TypeFoldable<'tcx>,
     {
         let needs_canonical_flags = if canonicalize_region_mode.any() {
             TypeFlags::KEEP_IN_LOCAL_TCX |
@@ -520,20 +520,12 @@ impl<'cx, 'tcx> Canonicalizer<'cx, 'tcx> {
             TypeFlags::HAS_CT_PLACEHOLDER
         };
 
-        let gcx = tcx.global_tcx();
-
         // Fast path: nothing that needs to be canonicalized.
         if !value.has_type_flags(needs_canonical_flags) {
-            let out_value = gcx.lift(value).unwrap_or_else(|| {
-                bug!(
-                    "failed to lift `{:?}` (nothing to canonicalize)",
-                    value
-                )
-            });
             let canon_value = Canonical {
                 max_universe: ty::UniverseIndex::ROOT,
                 variables: List::empty(),
-                value: out_value,
+                value: value.clone(),
             };
             return canon_value;
         }
@@ -553,13 +545,7 @@ impl<'cx, 'tcx> Canonicalizer<'cx, 'tcx> {
         // Once we have canonicalized `out_value`, it should not
         // contain anything that ties it to this inference context
         // anymore, so it should live in the global arena.
-        let out_value = gcx.lift(&out_value).unwrap_or_else(|| {
-            bug!(
-                "failed to lift `{:?}`, canonicalized from `{:?}`",
-                out_value,
-                value
-            )
-        });
+        debug_assert!(!out_value.has_type_flags(TypeFlags::KEEP_IN_LOCAL_TCX));
 
         let canonical_variables = tcx.intern_canonical_var_infos(&canonicalizer.variables);
 

src/librustc/infer/canonical/mod.rs

@@ -194,10 +194,10 @@ pub struct QueryResponse<'tcx, R> {
     pub value: R,
 }
 
-pub type Canonicalized<'tcx, V> = Canonical<'tcx, <V as Lift<'tcx>>::Lifted>;
+pub type Canonicalized<'tcx, V> = Canonical<'tcx, V>;
 
 pub type CanonicalizedQueryResponse<'tcx, T> =
-    &'tcx Canonical<'tcx, QueryResponse<'tcx, <T as Lift<'tcx>>::Lifted>>;
+    &'tcx Canonical<'tcx, QueryResponse<'tcx, T>>;
 
 /// Indicates whether or not we were able to prove the query to be
 /// true.

src/librustc/infer/canonical/query_response.rs

@@ -26,7 +26,7 @@ use crate::traits::TraitEngine;
 use crate::traits::{Obligation, ObligationCause, PredicateObligation};
 use crate::ty::fold::TypeFoldable;
 use crate::ty::subst::{Kind, UnpackedKind};
-use crate::ty::{self, BoundVar, InferConst, Lift, Ty, TyCtxt};
+use crate::ty::{self, BoundVar, InferConst, Ty, TyCtxt};
 use crate::util::captures::Captures;
 
 impl<'tcx> InferCtxtBuilder<'tcx> {
@@ -53,8 +53,8 @@ impl<'tcx> InferCtxtBuilder<'tcx> {
     ) -> Fallible<CanonicalizedQueryResponse<'tcx, R>>
     where
         K: TypeFoldable<'tcx>,
-        R: Debug + Lift<'tcx> + TypeFoldable<'tcx>,
-        Canonical<'tcx, <QueryResponse<'tcx, R> as Lift<'tcx>>::Lifted>: ArenaAllocatable,
+        R: Debug + TypeFoldable<'tcx>,
+        Canonical<'tcx, QueryResponse<'tcx, R>>: ArenaAllocatable,
     {
         self.enter_with_canonical(
             DUMMY_SP,
@@ -99,8 +99,8 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
         fulfill_cx: &mut dyn TraitEngine<'tcx>,
     ) -> Fallible<CanonicalizedQueryResponse<'tcx, T>>
     where
-        T: Debug + Lift<'tcx> + TypeFoldable<'tcx>,
-        Canonical<'tcx, <QueryResponse<'tcx, T> as Lift<'tcx>>::Lifted>: ArenaAllocatable,
+        T: Debug + TypeFoldable<'tcx>,
+        Canonical<'tcx, QueryResponse<'tcx, T>>: ArenaAllocatable,
     {
         let query_response = self.make_query_response(inference_vars, answer, fulfill_cx)?;
         let canonical_result = self.canonicalize_response(&query_response);
@@ -126,9 +126,9 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
         &self,
         inference_vars: CanonicalVarValues<'tcx>,
         answer: T,
-    ) -> Canonical<'tcx, QueryResponse<'tcx, <T as Lift<'tcx>>::Lifted>>
+    ) -> Canonical<'tcx, QueryResponse<'tcx, T>>
     where
-        T: Debug + Lift<'tcx> + TypeFoldable<'tcx>,
+        T: Debug + TypeFoldable<'tcx>,
     {
         self.canonicalize_response(&QueryResponse {
             var_values: inference_vars,
@@ -147,7 +147,7 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
         fulfill_cx: &mut dyn TraitEngine<'tcx>,
     ) -> Result<QueryResponse<'tcx, T>, NoSolution>
     where
-        T: Debug + TypeFoldable<'tcx> + Lift<'tcx>,
+        T: Debug + TypeFoldable<'tcx>,
     {
         let tcx = self.tcx;
 

src/librustc/infer/opaque_types/mod.rs

@@ -469,11 +469,6 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             definition_ty
         );
 
-        // We can unwrap here because our reverse mapper always
-        // produces things with 'tcx lifetime, though the type folder
-        // obscures that.
-        let definition_ty = gcx.lift(&definition_ty).unwrap();
-
         definition_ty
     }
 }

src/librustc/middle/mem_categorization.rs

@@ -819,10 +819,7 @@ impl<'a, 'tcx> MemCategorizationContext<'a, 'tcx> {
                              .unwrap_or(ty::ClosureKind::LATTICE_BOTTOM),
 
                     None =>
-                        self.tcx.global_tcx()
-                                .lift(&closure_substs)
-                                .expect("no inference cx, but inference variables in closure ty")
-                                .closure_kind(closure_def_id, self.tcx.global_tcx()),
+                        closure_substs.closure_kind(closure_def_id, self.tcx.global_tcx()),
                 }
             }
             _ => span_bug!(span, "unexpected type for fn in mem_categorization: {:?}", ty),

src/librustc/traits/codegen/mod.rs

@@ -141,9 +141,9 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         &self,
         fulfill_cx: &mut FulfillmentContext<'tcx>,
         result: &T,
-    ) -> T::Lifted
+    ) -> T
     where
-        T: TypeFoldable<'tcx> + ty::Lift<'tcx>,
+        T: TypeFoldable<'tcx>,
     {
         debug!("drain_fulfillment_cx_or_panic()");
 
@@ -155,10 +155,6 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         }
 
         let result = self.resolve_vars_if_possible(result);
-        let result = self.tcx.erase_regions(&result);
-
-        self.tcx.lift_to_global(&result).unwrap_or_else(||
-            bug!("Uninferred types/regions/consts in `{:?}`", result)
-        )
+        self.tcx.erase_regions(&result)
     }
 }

src/librustc/traits/project.rs

@@ -409,7 +409,6 @@ impl<'a, 'b, 'tcx> TypeFolder<'tcx> for AssocTypeNormalizer<'a, 'b, 'tcx> {
                             promoted: None
                         };
                         if let Ok(evaluated) = tcx.const_eval(param_env.and(cid)) {
-                            let substs = tcx.lift_to_global(&substs).unwrap();
                             let evaluated = evaluated.subst(tcx, substs);
                             return evaluated;
                         }

src/librustc/traits/query/normalize.rs

@@ -203,7 +203,6 @@ impl<'cx, 'tcx> TypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
                             promoted: None,
                         };
                         if let Ok(evaluated) = tcx.const_eval(param_env.and(cid)) {
-                            let substs = tcx.lift_to_global(&substs).unwrap();
                             let evaluated = evaluated.subst(tcx, substs);
                             return evaluated;
                         }

src/librustc/traits/query/type_op/mod.rs

@@ -8,7 +8,7 @@ use std::rc::Rc;
 use crate::traits::query::Fallible;
 use crate::traits::ObligationCause;
 use crate::ty::fold::TypeFoldable;
-use crate::ty::{Lift, ParamEnvAnd, TyCtxt};
+use crate::ty::{ParamEnvAnd, TyCtxt};
 
 pub mod ascribe_user_type;
 pub mod custom;
@@ -44,8 +44,8 @@ pub trait TypeOp<'tcx>: Sized + fmt::Debug {
 /// which produces the resulting query region constraints.
 ///
 /// [c]: https://rust-lang.github.io/rustc-guide/traits/canonicalization.html
-pub trait QueryTypeOp<'tcx>: fmt::Debug + Sized + TypeFoldable<'tcx> + Lift<'tcx> {
-    type QueryResponse: TypeFoldable<'tcx> + Lift<'tcx>;
+pub trait QueryTypeOp<'tcx>: fmt::Debug + Sized + TypeFoldable<'tcx> + 'tcx {
+    type QueryResponse: TypeFoldable<'tcx>;
 
     /// Give query the option for a simple fast path that never
     /// actually hits the tcx cache lookup etc. Return `Some(r)` with

src/librustc/traits/query/type_op/normalize.rs

@@ -20,7 +20,7 @@ where
 
 impl<'tcx, T> super::QueryTypeOp<'tcx> for Normalize<T>
 where
-    T: Normalizable<'tcx>,
+    T: Normalizable<'tcx> + 'tcx,
 {
     type QueryResponse = T;
 

src/librustc/traits/specialize/mod.rs

@@ -132,12 +132,7 @@ pub fn find_associated_item<'tcx>(
                 let substs = substs.rebase_onto(tcx, trait_def_id, impl_data.substs);
                 let substs = translate_substs(&infcx, param_env, impl_data.impl_def_id,
                                               substs, node_item.node);
-                let substs = infcx.tcx.erase_regions(&substs);
-                tcx.lift(&substs).unwrap_or_else(||
-                    bug!("find_method: translate_substs \
-                          returned {:?} which contains inference types/regions",
-                         substs)
-                )
+                infcx.tcx.erase_regions(&substs)
             });
             (node_item.item.def_id, substs)
         }

src/librustc/ty/error.rs

@@ -192,9 +192,12 @@ impl<'tcx> ty::TyS<'tcx> {
 
             ty::Adt(def, _) => format!("{} `{}`", def.descr(), tcx.def_path_str(def.did)).into(),
             ty::Foreign(def_id) => format!("extern type `{}`", tcx.def_path_str(def_id)).into(),
-            ty::Array(_, n) => match n.assert_usize(tcx) {
-                Some(n) => format!("array of {} elements", n).into(),
-                None => "array".into(),
+            ty::Array(_, n) => {
+                let n = tcx.lift_to_global(&n).unwrap();
+                match n.assert_usize(tcx) {
+                    Some(n) => format!("array of {} elements", n).into(),
+                    None => "array".into(),
+                }
             }
             ty::Slice(_) => "slice".into(),
             ty::RawPtr(_) => "*-ptr".into(),

src/librustc/ty/sty.rs

@@ -2262,7 +2262,6 @@ impl<'tcx> Const<'tcx> {
 
     #[inline]
     pub fn from_bits(tcx: TyCtxt<'tcx>, bits: u128, ty: ParamEnvAnd<'tcx, Ty<'tcx>>) -> &'tcx Self {
-        let ty = tcx.lift_to_global(&ty).unwrap();
         let size = tcx.layout_of(ty).unwrap_or_else(|e| {
             panic!("could not compute layout for {:?}: {:?}", ty, e)
         }).size;
@@ -2289,7 +2288,6 @@ impl<'tcx> Const<'tcx> {
         if self.ty != ty.value {
             return None;
         }
-        let ty = tcx.lift_to_global(&ty).unwrap();
         let size = tcx.layout_of(ty).ok()?.size;
         self.val.try_to_bits(size)
     }
@@ -2300,15 +2298,14 @@ impl<'tcx> Const<'tcx> {
     }
 
     #[inline]
-    pub fn assert_bits(&self, tcx: TyCtxt<'_>, ty: ParamEnvAnd<'tcx, Ty<'tcx>>) -> Option<u128> {
+    pub fn assert_bits(&self, tcx: TyCtxt<'tcx>, ty: ParamEnvAnd<'tcx, Ty<'tcx>>) -> Option<u128> {
         assert_eq!(self.ty, ty.value);
-        let ty = tcx.lift_to_global(&ty).unwrap();
         let size = tcx.layout_of(ty).ok()?.size;
         self.val.try_to_bits(size)
     }
 
     #[inline]
-    pub fn assert_bool(&self, tcx: TyCtxt<'_>) -> Option<bool> {
+    pub fn assert_bool(&self, tcx: TyCtxt<'tcx>) -> Option<bool> {
         self.assert_bits(tcx, ParamEnv::empty().and(tcx.types.bool)).and_then(|v| match v {
             0 => Some(false),
             1 => Some(true),
@@ -2317,18 +2314,18 @@ impl<'tcx> Const<'tcx> {
     }
 
     #[inline]
-    pub fn assert_usize(&self, tcx: TyCtxt<'_>) -> Option<u64> {
+    pub fn assert_usize(&self, tcx: TyCtxt<'tcx>) -> Option<u64> {
         self.assert_bits(tcx, ParamEnv::empty().and(tcx.types.usize)).map(|v| v as u64)
     }
 
     #[inline]
-    pub fn unwrap_bits(&self, tcx: TyCtxt<'_>, ty: ParamEnvAnd<'tcx, Ty<'tcx>>) -> u128 {
+    pub fn unwrap_bits(&self, tcx: TyCtxt<'tcx>, ty: ParamEnvAnd<'tcx, Ty<'tcx>>) -> u128 {
         self.assert_bits(tcx, ty).unwrap_or_else(||
             bug!("expected bits of {}, got {:#?}", ty.value, self))
     }
 
     #[inline]
-    pub fn unwrap_usize(&self, tcx: TyCtxt<'_>) -> u64 {
+    pub fn unwrap_usize(&self, tcx: TyCtxt<'tcx>) -> u64 {
         self.assert_usize(tcx).unwrap_or_else(||
             bug!("expected constant usize, got {:#?}", self))
     }

src/librustc_mir/borrow_check/mod.rs

@@ -670,7 +670,7 @@ impl<'cx, 'tcx> DataflowResultsConsumer<'cx, 'tcx> for MirBorrowckCtxt<'cx, 'tcx
                 // "Lift" into the gcx -- once regions are erased, this type should be in the
                 // global arenas; this "lift" operation basically just asserts that is true, but
                 // that is useful later.
-                let drop_place_ty = gcx.lift(&drop_place_ty).unwrap();
+                gcx.lift_to_global(&drop_place_ty).unwrap();
 
                 debug!("visit_terminator_drop \
                         loc: {:?} term: {:?} drop_place: {:?} drop_place_ty: {:?} span: {:?}",

src/librustc_mir/borrow_check/nll/region_infer/mod.rs

@@ -863,8 +863,8 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         });
         debug!("try_promote_type_test_subject: folded ty = {:?}", ty);
 
-        // `lift` will only fail if we failed to promote some region.
-        let ty = gcx.lift(&ty)?;
+        // `lift_to_global` will only fail if we failed to promote some region.
+        gcx.lift_to_global(&ty)?;
 
         Some(ClosureOutlivesSubject::Ty(ty))
     }

src/librustc_mir/borrow_check/nll/type_check/mod.rs

@@ -1866,7 +1866,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         // `Sized` bound in no way depends on precise regions, so this
         // shouldn't affect `is_sized`.
         let gcx = tcx.global_tcx();
-        let erased_ty = gcx.lift(&tcx.erase_regions(&ty)).unwrap();
+        let erased_ty = tcx.erase_regions(&ty);
         if !erased_ty.is_sized(gcx.at(span), self.param_env) {
             // in current MIR construction, all non-control-flow rvalue
             // expressions evaluate through `as_temp` or `into` a return
@@ -2652,7 +2652,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
 
     fn normalize<T>(&mut self, value: T, location: impl NormalizeLocation) -> T
     where
-        T: type_op::normalize::Normalizable<'tcx> + Copy,
+        T: type_op::normalize::Normalizable<'tcx> + Copy + 'tcx,
     {
         debug!("normalize(value={:?}, location={:?})", value, location);
         let param_env = self.param_env;

src/librustc_mir/build/expr/as_rvalue.rs

@@ -569,7 +569,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 
     // Helper to get a `-1` value of the appropriate type
     fn neg_1_literal(&mut self, span: Span, ty: Ty<'tcx>) -> Operand<'tcx> {
-        let param_ty = ty::ParamEnv::empty().and(self.hir.tcx().lift_to_global(&ty).unwrap());
+        let param_ty = ty::ParamEnv::empty().and(ty);
         let bits = self.hir.tcx().layout_of(param_ty).unwrap().size.bits();
         let n = (!0u128) >> (128 - bits);
         let literal = ty::Const::from_bits(self.hir.tcx(), n, param_ty);
@@ -580,7 +580,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
     // Helper to get the minimum value of the appropriate type
     fn minval_literal(&mut self, span: Span, ty: Ty<'tcx>) -> Operand<'tcx> {
         assert!(ty.is_signed());
-        let param_ty = ty::ParamEnv::empty().and(self.hir.tcx().lift_to_global(&ty).unwrap());
+        let param_ty = ty::ParamEnv::empty().and(ty);
         let bits = self.hir.tcx().layout_of(param_ty).unwrap().size.bits();
         let n = 1 << (bits - 1);
         let literal = ty::Const::from_bits(self.hir.tcx(), n, param_ty);

src/librustc_mir/dataflow/drop_flag_effects.rs

@@ -151,7 +151,7 @@ pub(crate) fn on_all_drop_children_bits<'tcx, F>(
         debug!("on_all_drop_children_bits({:?}, {:?} : {:?})", path, place, ty);
 
         let gcx = tcx.global_tcx();
-        let erased_ty = gcx.lift(&tcx.erase_regions(&ty)).unwrap();
+        let erased_ty = tcx.erase_regions(&ty);
         if erased_ty.needs_drop(gcx, ctxt.param_env) {
             each_child(child);
         } else {

src/librustc_mir/hair/constant.rs

@@ -18,7 +18,7 @@ crate fn lit_to_const<'tcx>(
     use syntax::ast::*;
 
     let trunc = |n| {
-        let param_ty = ParamEnv::reveal_all().and(tcx.lift_to_global(&ty).unwrap());
+        let param_ty = ParamEnv::reveal_all().and(ty);
         let width = tcx.layout_of(param_ty).map_err(|_| LitToConstError::Reported)?.size;
         trace!("trunc {} with size {} and shift {}", n, width.bits(), 128 - width.bits());
         let result = truncate(n, width);

src/librustc_mir/hair/cx/mod.rs

@@ -191,12 +191,7 @@ impl<'a, 'tcx> Cx<'a, 'tcx> {
     }
 
     pub fn needs_drop(&mut self, ty: Ty<'tcx>) -> bool {
-        let (ty, param_env) = self.tcx.lift_to_global(&(ty, self.param_env)).unwrap_or_else(|| {
-            bug!("MIR: Cx::needs_drop({:?}, {:?}) got \
-                  type with inference types/regions",
-                 ty, self.param_env);
-        });
-        ty.needs_drop(self.tcx.global_tcx(), param_env)
+        ty.needs_drop(self.tcx.global_tcx(), self.param_env)
     }
 
     pub fn tcx(&self) -> TyCtxt<'tcx> {

src/librustc_mir/hair/pattern/_match.rs

@@ -1311,7 +1311,7 @@ fn is_useful_specialized<'p, 'a: 'p, 'tcx: 'a>(
 /// Returns `None` in case of a catch-all, which can't be specialized.
 fn pat_constructors<'tcx>(cx: &mut MatchCheckCtxt<'_, 'tcx>,
                           pat: &Pattern<'tcx>,
-                          pcx: PatternContext<'_>)
+                          pcx: PatternContext<'tcx>)
                           -> Option<Vec<Constructor<'tcx>>>
 {
     match *pat.kind {

src/librustc_traits/normalize_erasing_regions.rs

@@ -37,8 +37,7 @@ fn normalize_ty_after_erasing_regions<'tcx>(
                 );
 
                 let normalized_value = infcx.resolve_vars_if_possible(&normalized_value);
-                let normalized_value = infcx.tcx.erase_regions(&normalized_value);
-                tcx.lift_to_global(&normalized_value).unwrap()
+                infcx.tcx.erase_regions(&normalized_value)
             }
             Err(NoSolution) => bug!("could not fully normalize `{:?}`", value),
         }