remove Canonicalization trait, which serves no purpose

Author: nikomatsakis

src/librustc/infer/canonical/canonicalizer.rs

@@ -17,13 +17,13 @@
 
 use infer::canonical::{
     Canonical, CanonicalTyVarKind, CanonicalVarInfo, CanonicalVarKind, CanonicalVarValues,
-    Canonicalize,
+    Canonicalized,
 };
 use infer::InferCtxt;
 use std::sync::atomic::Ordering;
 use ty::fold::{TypeFoldable, TypeFolder};
 use ty::subst::Kind;
-use ty::{self, CanonicalVar, Slice, Ty, TyCtxt, TypeFlags};
+use ty::{self, CanonicalVar, Lift, Slice, Ty, TyCtxt, TypeFlags};
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::indexed_vec::IndexVec;
@@ -44,9 +44,12 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
     /// out the [chapter in the rustc guide][c].
     ///
     /// [c]: https://rust-lang-nursery.github.io/rustc-guide/traits-canonicalization.html#canonicalizing-the-query
-    pub fn canonicalize_query<V>(&self, value: &V) -> (V::Canonicalized, CanonicalVarValues<'tcx>)
+    pub fn canonicalize_query<V>(
+        &self,
+        value: &V,
+    ) -> (Canonicalized<'gcx, V>, CanonicalVarValues<'tcx>)
     where
-        V: Canonicalize<'gcx, 'tcx>,
+        V: TypeFoldable<'tcx> + Lift<'gcx>,
     {
         self.tcx
             .sess
@@ -90,9 +93,9 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
     pub fn canonicalize_response<V>(
         &self,
         value: &V,
-    ) -> (V::Canonicalized, CanonicalVarValues<'tcx>)
+    ) -> (Canonicalized<'gcx, V>, CanonicalVarValues<'tcx>)
     where
-        V: Canonicalize<'gcx, 'tcx>,
+        V: TypeFoldable<'tcx> + Lift<'gcx>,
     {
         Canonicalizer::canonicalize(
             value,
@@ -233,9 +236,9 @@ impl<'cx, 'gcx, 'tcx> Canonicalizer<'cx, 'gcx, 'tcx> {
         infcx: Option<&'cx InferCtxt<'cx, 'gcx, 'tcx>>,
         tcx: TyCtxt<'cx, 'gcx, 'tcx>,
         canonicalize_all_free_regions: CanonicalizeAllFreeRegions,
-    ) -> (V::Canonicalized, CanonicalVarValues<'tcx>)
+    ) -> (Canonicalized<'gcx, V>, CanonicalVarValues<'tcx>)
     where
-        V: Canonicalize<'gcx, 'tcx>,
+        V: TypeFoldable<'tcx> + Lift<'gcx>,
     {
         debug_assert!(
             !value.has_type_flags(TypeFlags::HAS_CANONICAL_VARS),
@@ -254,13 +257,10 @@ impl<'cx, 'gcx, 'tcx> Canonicalizer<'cx, 'gcx, 'tcx> {
         // Fast path: nothing that needs to be canonicalized.
         if !value.has_type_flags(needs_canonical_flags) {
             let out_value = gcx.lift(value).unwrap();
-            let canon_value = V::intern(
-                gcx,
-                Canonical {
-                    variables: Slice::empty(),
-                    value: out_value,
-                },
-            );
+            let canon_value = Canonical {
+                variables: Slice::empty(),
+                value: out_value,
+            };
             let values = CanonicalVarValues {
                 var_values: IndexVec::default(),
             };
@@ -291,13 +291,10 @@ impl<'cx, 'gcx, 'tcx> Canonicalizer<'cx, 'gcx, 'tcx> {
 
         let canonical_variables = tcx.intern_canonical_var_infos(&canonicalizer.variables.raw);
 
-        let canonical_value = V::intern(
-            gcx,
-            Canonical {
-                variables: canonical_variables,
-                value: out_value,
-            },
-        );
+        let canonical_value = Canonical {
+            variables: canonical_variables,
+            value: out_value,
+        };
         let canonical_var_values = CanonicalVarValues {
             var_values: canonicalizer.var_values,
         };

src/librustc/infer/canonical/mod.rs

@@ -35,7 +35,6 @@ use infer::{InferCtxt, RegionVariableOrigin, TypeVariableOrigin};
 use rustc_data_structures::indexed_vec::IndexVec;
 use rustc_data_structures::sync::Lrc;
 use serialize::UseSpecializedDecodable;
-use std::fmt::Debug;
 use std::ops::Index;
 use syntax::codemap::Span;
 use ty::fold::TypeFoldable;
@@ -124,6 +123,8 @@ pub struct QueryResult<'tcx, R> {
     pub value: R,
 }
 
+pub type Canonicalized<'gcx, V> = Canonical<'gcx, <V as Lift<'gcx>>::Lifted>;
+
 pub type CanonicalizedQueryResult<'gcx, T> =
     Lrc<Canonical<'gcx, QueryResult<'gcx, <T as Lift<'gcx>>::Lifted>>>;
 
@@ -184,19 +185,6 @@ impl<'tcx, R> Canonical<'tcx, QueryResult<'tcx, R>> {
 
 pub type QueryRegionConstraint<'tcx> = ty::Binder<ty::OutlivesPredicate<Kind<'tcx>, Region<'tcx>>>;
 
-/// Trait implemented by values that can be canonicalized. It mainly
-/// serves to identify the interning table we will use.
-pub trait Canonicalize<'gcx: 'tcx, 'tcx>: TypeFoldable<'tcx> + Lift<'gcx> {
-    type Canonicalized: 'gcx + Debug;
-
-    /// After a value has been fully canonicalized and lifted, this
-    /// method will allocate it in a global arena.
-    fn intern(
-        gcx: TyCtxt<'_, 'gcx, 'gcx>,
-        value: Canonical<'gcx, Self::Lifted>,
-    ) -> Self::Canonicalized;
-}
-
 impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
     /// Creates a substitution S for the canonical value with fresh
     /// inference variables and applies it to the canonical value.
@@ -344,18 +332,3 @@ impl<'tcx> Index<CanonicalVar> for CanonicalVarValues<'tcx> {
         &self.var_values[value]
     }
 }
-
-impl<'gcx: 'tcx, 'tcx, T> Canonicalize<'gcx, 'tcx> for QueryResult<'tcx, T>
-where
-    T: TypeFoldable<'tcx> + Lift<'gcx>,
-{
-    // we ought to intern this, but I'm too lazy just now
-    type Canonicalized = Lrc<Canonical<'gcx, QueryResult<'gcx, T::Lifted>>>;
-
-    fn intern(
-        _gcx: TyCtxt<'_, 'gcx, 'gcx>,
-        value: Canonical<'gcx, Self::Lifted>,
-    ) -> Self::Canonicalized {
-        Lrc::new(value)
-    }
-}

src/librustc/infer/canonical/query_result.rs

@@ -19,13 +19,14 @@
 
 use infer::canonical::substitute::substitute_value;
 use infer::canonical::{
-    Canonical, CanonicalVarValues, Canonicalize, CanonicalizedQueryResult, Certainty,
+    Canonical, CanonicalVarValues, CanonicalizedQueryResult, Certainty,
     QueryRegionConstraint, QueryResult,
 };
 use infer::region_constraints::{Constraint, RegionConstraintData};
 use infer::{InferCtxt, InferOk, InferResult, RegionObligation};
 use rustc_data_structures::indexed_vec::Idx;
 use rustc_data_structures::indexed_vec::IndexVec;
+use rustc_data_structures::sync::Lrc;
 use std::fmt::Debug;
 use syntax::ast;
 use traits::query::NoSolution;
@@ -72,7 +73,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
             canonical_result
         );
 
-        Ok(canonical_result)
+        Ok(Lrc::new(canonical_result))
     }
 
     /// Helper for `make_canonicalized_query_result` that does
@@ -84,8 +85,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
         fulfill_cx: &mut FulfillmentContext<'tcx>,
     ) -> Result<QueryResult<'tcx, T>, NoSolution>
     where
-        T: Debug,
-        QueryResult<'tcx, T>: Canonicalize<'gcx, 'tcx>,
+        T: Debug + TypeFoldable<'tcx> + Lift<'gcx>,
     {
         let tcx = self.tcx;
 

src/librustc/traits/mod.rs

@@ -27,7 +27,6 @@ use ty::subst::Substs;
 use ty::{self, AdtKind, Slice, Ty, TyCtxt, GenericParamDefKind, ToPredicate};
 use ty::error::{ExpectedFound, TypeError};
 use ty::fold::{TypeFolder, TypeFoldable, TypeVisitor};
-use infer::canonical::{Canonical, Canonicalize};
 use infer::{InferCtxt};
 
 use rustc_data_structures::sync::Lrc;
@@ -1015,18 +1014,6 @@ pub fn provide(providers: &mut ty::query::Providers) {
     };
 }
 
-impl<'gcx: 'tcx, 'tcx> Canonicalize<'gcx, 'tcx> for ty::ParamEnvAnd<'tcx, Goal<'tcx>> {
-    // we ought to intern this, but I'm too lazy just now
-    type Canonicalized = Canonical<'gcx, ty::ParamEnvAnd<'gcx, Goal<'gcx>>>;
-
-    fn intern(
-        _gcx: TyCtxt<'_, 'gcx, 'gcx>,
-        value: Canonical<'gcx, Self::Lifted>,
-    ) -> Self::Canonicalized {
-        value
-    }
-}
-
 pub trait ExClauseFold<'tcx>
 where
     Self: chalk_engine::context::Context + Clone,
@@ -1053,20 +1040,3 @@ where
         tcx: TyCtxt<'a, 'gcx, 'tcx>,
     ) -> Option<Self::LiftedExClause>;
 }
-
-impl<'gcx: 'tcx, 'tcx, C> Canonicalize<'gcx, 'tcx> for chalk_engine::ExClause<C>
-where
-    C: chalk_engine::context::Context + Clone,
-    C: ExClauseLift<'gcx> + ExClauseFold<'tcx>,
-    C::Substitution: Clone,
-    C::RegionConstraint: Clone,
-{
-    type Canonicalized = Canonical<'gcx, C::LiftedExClause>;
-
-    fn intern(
-        _gcx: TyCtxt<'_, 'gcx, 'gcx>,
-        value: Canonical<'gcx, Self::Lifted>,
-    ) -> Self::Canonicalized {
-        value
-    }
-}

src/librustc/traits/query/dropck_outlives.rs

@@ -9,12 +9,10 @@
 // except according to those terms.
 
 use infer::at::At;
-use infer::canonical::{Canonical, Canonicalize};
 use infer::InferOk;
 use std::iter::FromIterator;
-use traits::query::CanonicalTyGoal;
-use ty::{self, Ty, TyCtxt};
 use ty::subst::Kind;
+use ty::{self, Ty, TyCtxt};
 
 impl<'cx, 'gcx, 'tcx> At<'cx, 'gcx, 'tcx> {
     /// Given a type `ty` of some value being dropped, computes a set
@@ -44,7 +42,10 @@ impl<'cx, 'gcx, 'tcx> At<'cx, 'gcx, 'tcx> {
         // any destructor.
         let tcx = self.infcx.tcx;
         if trivial_dropck_outlives(tcx, ty) {
-            return InferOk { value: vec![], obligations: vec![] };
+            return InferOk {
+                value: vec![],
+                obligations: vec![],
+            };
         }
 
         let gcx = tcx.global_tcx();
@@ -152,17 +153,6 @@ impl<'tcx> FromIterator<DtorckConstraint<'tcx>> for DtorckConstraint<'tcx> {
         result
     }
 }
-impl<'gcx: 'tcx, 'tcx> Canonicalize<'gcx, 'tcx> for ty::ParamEnvAnd<'tcx, Ty<'tcx>> {
-    type Canonicalized = CanonicalTyGoal<'gcx>;
-
-    fn intern(
-        _gcx: TyCtxt<'_, 'gcx, 'gcx>,
-        value: Canonical<'gcx, Self::Lifted>,
-    ) -> Self::Canonicalized {
-        value
-    }
-}
-
 BraceStructTypeFoldableImpl! {
     impl<'tcx> TypeFoldable<'tcx> for DropckOutlivesResult<'tcx> {
         kinds, overflows

src/librustc/traits/query/evaluate_obligation.rs

@@ -9,11 +9,8 @@
 // except according to those terms.
 
 use infer::InferCtxt;
-use infer::canonical::{Canonical, Canonicalize};
 use traits::{EvaluationResult, PredicateObligation, SelectionContext,
              TraitQueryMode, OverflowError};
-use traits::query::CanonicalPredicateGoal;
-use ty::{ParamEnvAnd, Predicate, TyCtxt};
 
 impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
     /// Evaluates whether the predicate can be satisfied (by any means)
@@ -57,14 +54,3 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
         }
     }
 }
-
-impl<'gcx: 'tcx, 'tcx> Canonicalize<'gcx, 'tcx> for ParamEnvAnd<'tcx, Predicate<'tcx>> {
-    type Canonicalized = CanonicalPredicateGoal<'gcx>;
-
-    fn intern(
-        _gcx: TyCtxt<'_, 'gcx, 'gcx>,
-        value: Canonical<'gcx, Self::Lifted>,
-    ) -> Self::Canonicalized {
-        value
-    }
-}

src/librustc/traits/query/normalize.rs

@@ -14,11 +14,9 @@
 
 use infer::{InferCtxt, InferOk};
 use infer::at::At;
-use infer::canonical::{Canonical, Canonicalize};
 use middle::const_val::ConstVal;
 use mir::interpret::GlobalId;
 use traits::{Obligation, ObligationCause, PredicateObligation, Reveal};
-use traits::query::CanonicalProjectionGoal;
 use traits::project::Normalized;
 use ty::{self, Ty, TyCtxt};
 use ty::fold::{TypeFoldable, TypeFolder};
@@ -250,17 +248,6 @@ BraceStructLiftImpl! {
     }
 }
 
-impl<'gcx: 'tcx, 'tcx> Canonicalize<'gcx, 'tcx> for ty::ParamEnvAnd<'tcx, ty::ProjectionTy<'tcx>> {
-    type Canonicalized = CanonicalProjectionGoal<'gcx>;
-
-    fn intern(
-        _gcx: TyCtxt<'_, 'gcx, 'gcx>,
-        value: Canonical<'gcx, Self::Lifted>,
-    ) -> Self::Canonicalized {
-        value
-    }
-}
-
 impl_stable_hash_for!(struct NormalizationResult<'tcx> {
     normalized_ty
 });

src/librustc/ty/mod.rs

@@ -21,7 +21,7 @@ use hir::map::DefPathData;
 use hir::svh::Svh;
 use ich::Fingerprint;
 use ich::StableHashingContext;
-use infer::canonical::{Canonical, Canonicalize};
+use infer::canonical::Canonical;
 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
 use middle::privacy::AccessLevels;
 use middle::resolve_lifetime::ObjectLifetimeDefault;
@@ -591,15 +591,6 @@ impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
 
 pub type CanonicalTy<'gcx> = Canonical<'gcx, Ty<'gcx>>;
 
-impl <'gcx: 'tcx, 'tcx> Canonicalize<'gcx, 'tcx> for Ty<'tcx> {
-    type Canonicalized = CanonicalTy<'gcx>;
-
-    fn intern(_gcx: TyCtxt<'_, 'gcx, 'gcx>,
-              value: Canonical<'gcx, Self::Lifted>) -> Self::Canonicalized {
-        value
-    }
-}
-
 extern {
     /// A dummy type used to force Slice to by unsized without requiring fat pointers
     type OpaqueSliceContents;

src/librustc_traits/chalk_context.rs

@@ -10,9 +10,7 @@
 
 use chalk_engine::fallible::Fallible as ChalkEngineFallible;
 use chalk_engine::{context, hh::HhGoal, DelayedLiteral, ExClause};
-use rustc::infer::canonical::{
-    Canonical, CanonicalVarValues, Canonicalize, QueryRegionConstraint, QueryResult,
-};
+use rustc::infer::canonical::{Canonical, CanonicalVarValues, QueryRegionConstraint, QueryResult};
 use rustc::infer::{InferCtxt, InferOk, LateBoundRegionConversionTime};
 use rustc::traits::{
     WellFormed,
@@ -519,14 +517,3 @@ BraceStructLiftImpl! {
         subst, constraints
     }
 }
-
-impl<'gcx: 'tcx, 'tcx> Canonicalize<'gcx, 'tcx> for ConstrainedSubst<'tcx> {
-    type Canonicalized = Canonical<'gcx, ConstrainedSubst<'gcx>>;
-
-    fn intern(
-        _gcx: TyCtxt<'_, 'gcx, 'gcx>,
-        value: Canonical<'gcx, ConstrainedSubst<'gcx>>,
-    ) -> Self::Canonicalized {
-        value
-    }
-}