Refactor the chalkify lowering process

scalexm · scalexm · commit 0347b32a26ef · 2018-06-04T18:21:14.000+02:00
diff --git a/src/librustc/ich/impls_ty.rs b/src/librustc/ich/impls_ty.rs
@@ -1382,16 +1382,46 @@ impl_stable_hash_for!(enum infer::canonical::Certainty {
     Proven, Ambiguous
 });
 
-impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for traits::WhereClauseAtom<'tcx> {
+impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for traits::WhereClause<'tcx> {
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
-        use traits::WhereClauseAtom::*;
+        use traits::WhereClause::*;
 
         mem::discriminant(self).hash_stable(hcx, hasher);
         match self {
             Implemented(trait_ref) => trait_ref.hash_stable(hcx, hasher),
             ProjectionEq(projection) => projection.hash_stable(hcx, hasher),
+            TypeOutlives(ty_outlives) => ty_outlives.hash_stable(hcx, hasher),
+            RegionOutlives(region_outlives) => region_outlives.hash_stable(hcx, hasher),
+        }
+    }
+}
+
+impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for traits::WellFormed<'tcx> {
+    fn hash_stable<W: StableHasherResult>(&self,
+                                          hcx: &mut StableHashingContext<'a>,
+                                          hasher: &mut StableHasher<W>) {
+        use traits::WellFormed::*;
+
+        mem::discriminant(self).hash_stable(hcx, hasher);
+        match self {
+            Trait(trait_ref) => trait_ref.hash_stable(hcx, hasher),
+            Ty(ty) => ty.hash_stable(hcx, hasher),
+        }
+    }
+}
+
+impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for traits::FromEnv<'tcx> {
+    fn hash_stable<W: StableHasherResult>(&self,
+                                          hcx: &mut StableHashingContext<'a>,
+                                          hasher: &mut StableHasher<W>) {
+        use traits::FromEnv::*;
+
+        mem::discriminant(self).hash_stable(hcx, hasher);
+        match self {
+            Trait(trait_ref) => trait_ref.hash_stable(hcx, hasher),
+            Ty(ty) => ty.hash_stable(hcx, hasher),
         }
     }
 }
@@ -1404,15 +1434,10 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for traits::DomainGoal<'tcx>
 
         mem::discriminant(self).hash_stable(hcx, hasher);
         match self {
-            Holds(where_clause) |
-            WellFormed(where_clause) |
-            FromEnv(where_clause) => where_clause.hash_stable(hcx, hasher),
-
-            WellFormedTy(ty) => ty.hash_stable(hcx, hasher),
+            Holds(wc) => wc.hash_stable(hcx, hasher),
+            WellFormed(wf) => wf.hash_stable(hcx, hasher),
+            FromEnv(from_env) => from_env.hash_stable(hcx, hasher),
             Normalize(projection) => projection.hash_stable(hcx, hasher),
-            FromEnvTy(ty) => ty.hash_stable(hcx, hasher),
-            RegionOutlives(predicate) => predicate.hash_stable(hcx, hasher),
-            TypeOutlives(predicate) => predicate.hash_stable(hcx, hasher),
         }
     }
 }
diff --git a/src/librustc/traits/mod.rs b/src/librustc/traits/mod.rs
@@ -269,29 +269,41 @@ pub type PredicateObligations<'tcx> = Vec<PredicateObligation<'tcx>>;
 pub type TraitObligations<'tcx> = Vec<TraitObligation<'tcx>>;
 
 /// The following types:
-/// * `WhereClauseAtom`
+/// * `WhereClause`
+/// * `WellFormed`
+/// * `FromEnv`
 /// * `DomainGoal`
 /// * `Goal`
 /// * `Clause`
 /// are used for representing the trait system in the form of
 /// logic programming clauses. They are part of the interface
 /// for the chalk SLG solver.
 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
-pub enum WhereClauseAtom<'tcx> {
+pub enum WhereClause<'tcx> {
     Implemented(ty::TraitPredicate<'tcx>),
     ProjectionEq(ty::ProjectionPredicate<'tcx>),
+    RegionOutlives(ty::RegionOutlivesPredicate<'tcx>),
+    TypeOutlives(ty::TypeOutlivesPredicate<'tcx>),
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
+pub enum WellFormed<'tcx> {
+    Trait(ty::TraitPredicate<'tcx>),
+    Ty(Ty<'tcx>),
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
+pub enum FromEnv<'tcx> {
+    Trait(ty::TraitPredicate<'tcx>),
+    Ty(Ty<'tcx>),
 }
 
 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
 pub enum DomainGoal<'tcx> {
-    Holds(WhereClauseAtom<'tcx>),
-    WellFormed(WhereClauseAtom<'tcx>),
-    FromEnv(WhereClauseAtom<'tcx>),
-    WellFormedTy(Ty<'tcx>),
+    Holds(WhereClause<'tcx>),
+    WellFormed(WellFormed<'tcx>),
+    FromEnv(FromEnv<'tcx>),
     Normalize(ty::ProjectionPredicate<'tcx>),
-    FromEnvTy(Ty<'tcx>),
-    RegionOutlives(ty::RegionOutlivesPredicate<'tcx>),
-    TypeOutlives(ty::TypeOutlivesPredicate<'tcx>),
 }
 
 pub type PolyDomainGoal<'tcx> = ty::Binder<DomainGoal<'tcx>>;
@@ -314,27 +326,27 @@ pub enum Goal<'tcx> {
 
 pub type Goals<'tcx> = &'tcx Slice<Goal<'tcx>>;
 
+impl<'tcx> DomainGoal<'tcx> {
+    pub fn into_goal(self) -> Goal<'tcx> {
+        Goal::DomainGoal(self)
+    }
+}
+
 impl<'tcx> Goal<'tcx> {
     pub fn from_poly_domain_goal<'a>(
         domain_goal: PolyDomainGoal<'tcx>,
         tcx: TyCtxt<'a, 'tcx, 'tcx>,
     ) -> Goal<'tcx> {
         match domain_goal.no_late_bound_regions() {
-            Some(p) => p.into(),
+            Some(p) => p.into_goal(),
             None => Goal::Quantified(
                 QuantifierKind::Universal,
-                domain_goal.map_bound(|p| tcx.mk_goal(Goal::from(p)))
+                domain_goal.map_bound(|p| tcx.mk_goal(p.into_goal()))
             ),
         }
     }
 }
 
-impl<'tcx> From<DomainGoal<'tcx>> for Goal<'tcx> {
-    fn from(domain_goal: DomainGoal<'tcx>) -> Self {
-        Goal::DomainGoal(domain_goal)
-    }
-}
-
 /// This matches the definition from Page 7 of "A Proof Procedure for the Logic of Hereditary
 /// Harrop Formulas".
 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
diff --git a/src/librustc/traits/structural_impls.rs b/src/librustc/traits/structural_impls.rs
@@ -405,33 +405,50 @@ BraceStructTypeFoldableImpl! {
     } where T: TypeFoldable<'tcx>
 }
 
-impl<'tcx> fmt::Display for traits::WhereClauseAtom<'tcx> {
+impl<'tcx> fmt::Display for traits::WhereClause<'tcx> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        use traits::WhereClauseAtom::*;
+        use traits::WhereClause::*;
 
         match self {
             Implemented(trait_ref) => write!(fmt, "Implemented({})", trait_ref),
             ProjectionEq(projection) => write!(fmt, "ProjectionEq({})", projection),
+            RegionOutlives(predicate) => write!(fmt, "RegionOutlives({})", predicate),
+            TypeOutlives(predicate) => write!(fmt, "TypeOutlives({})", predicate),
+        }
+    }
+}
+
+impl<'tcx> fmt::Display for traits::WellFormed<'tcx> {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        use traits::WellFormed::*;
+
+        match self {
+            Trait(trait_ref) => write!(fmt, "WellFormed({})", trait_ref),
+            Ty(ty) => write!(fmt, "WellFormed({})", ty),
+        }
+    }
+}
+
+impl<'tcx> fmt::Display for traits::FromEnv<'tcx> {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        use traits::FromEnv::*;
+
+        match self {
+            Trait(trait_ref) => write!(fmt, "FromEnv({})", trait_ref),
+            Ty(ty) => write!(fmt, "FromEnv({})", ty),
         }
     }
 }
 
 impl<'tcx> fmt::Display for traits::DomainGoal<'tcx> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         use traits::DomainGoal::*;
-        use traits::WhereClauseAtom::*;
 
         match self {
             Holds(wc) => write!(fmt, "{}", wc),
-            WellFormed(Implemented(trait_ref)) => write!(fmt, "WellFormed({})", trait_ref),
-            WellFormed(ProjectionEq(projection)) => write!(fmt, "WellFormed({})", projection),
-            FromEnv(Implemented(trait_ref)) => write!(fmt, "FromEnv({})", trait_ref),
-            FromEnv(ProjectionEq(projection)) => write!(fmt, "FromEnv({})", projection),
-            WellFormedTy(ty) => write!(fmt, "WellFormed({})", ty),
+            WellFormed(wf) => write!(fmt, "{}", wf),
+            FromEnv(from_env) => write!(fmt, "{}", from_env),
             Normalize(projection) => write!(fmt, "Normalize({})", projection),
-            FromEnvTy(ty) => write!(fmt, "FromEnv({})", ty),
-            RegionOutlives(predicate) => write!(fmt, "RegionOutlives({})", predicate),
-            TypeOutlives(predicate) => write!(fmt, "TypeOutlives({})", predicate),
         }
     }
 }
@@ -506,44 +523,70 @@ impl<'tcx> fmt::Display for traits::Clause<'tcx> {
 }
 
 EnumTypeFoldableImpl! {
-    impl<'tcx> TypeFoldable<'tcx> for traits::WhereClauseAtom<'tcx> {
-        (traits::WhereClauseAtom::Implemented)(trait_ref),
-        (traits::WhereClauseAtom::ProjectionEq)(projection),
+    impl<'tcx> TypeFoldable<'tcx> for traits::WhereClause<'tcx> {
+        (traits::WhereClause::Implemented)(trait_ref),
+        (traits::WhereClause::ProjectionEq)(projection),
+        (traits::WhereClause::TypeOutlives)(ty_outlives),
+        (traits::WhereClause::RegionOutlives)(region_outlives),
+    }
+}
+
+EnumLiftImpl! {
+    impl<'a, 'tcx> Lift<'tcx> for traits::WhereClause<'a> {
+        type Lifted = traits::WhereClause<'tcx>;
+        (traits::WhereClause::Implemented)(trait_ref),
+        (traits::WhereClause::ProjectionEq)(projection),
+        (traits::WhereClause::TypeOutlives)(ty_outlives),
+        (traits::WhereClause::RegionOutlives)(region_outlives),
+    }
+}
+
+EnumTypeFoldableImpl! {
+    impl<'tcx> TypeFoldable<'tcx> for traits::WellFormed<'tcx> {
+        (traits::WellFormed::Trait)(trait_ref),
+        (traits::WellFormed::Ty)(ty),
+    }
+}
+
+EnumLiftImpl! {
+    impl<'a, 'tcx> Lift<'tcx> for traits::WellFormed<'a> {
+        type Lifted = traits::WellFormed<'tcx>;
+        (traits::WellFormed::Trait)(trait_ref),
+        (traits::WellFormed::Ty)(ty),
+    }
+}
+
+EnumTypeFoldableImpl! {
+    impl<'tcx> TypeFoldable<'tcx> for traits::FromEnv<'tcx> {
+        (traits::FromEnv::Trait)(trait_ref),
+        (traits::FromEnv::Ty)(ty),
     }
 }
 
 EnumLiftImpl! {
-    impl<'a, 'tcx> Lift<'tcx> for traits::WhereClauseAtom<'a> {
-        type Lifted = traits::WhereClauseAtom<'tcx>;
-        (traits::WhereClauseAtom::Implemented)(trait_ref),
-        (traits::WhereClauseAtom::ProjectionEq)(projection),
+    impl<'a, 'tcx> Lift<'tcx> for traits::FromEnv<'a> {
+        type Lifted = traits::FromEnv<'tcx>;
+        (traits::FromEnv::Trait)(trait_ref),
+        (traits::FromEnv::Ty)(ty),
     }
 }
 
 EnumTypeFoldableImpl! {
     impl<'tcx> TypeFoldable<'tcx> for traits::DomainGoal<'tcx> {
         (traits::DomainGoal::Holds)(wc),
-        (traits::DomainGoal::WellFormed)(wc),
-        (traits::DomainGoal::FromEnv)(wc),
-        (traits::DomainGoal::WellFormedTy)(ty),
+        (traits::DomainGoal::WellFormed)(wf),
+        (traits::DomainGoal::FromEnv)(from_env),
         (traits::DomainGoal::Normalize)(projection),
-        (traits::DomainGoal::FromEnvTy)(ty),
-        (traits::DomainGoal::RegionOutlives)(predicate),
-        (traits::DomainGoal::TypeOutlives)(predicate),
     }
 }
 
 EnumLiftImpl! {
     impl<'a, 'tcx> Lift<'tcx> for traits::DomainGoal<'a> {
         type Lifted = traits::DomainGoal<'tcx>;
         (traits::DomainGoal::Holds)(wc),
-        (traits::DomainGoal::WellFormed)(wc),
-        (traits::DomainGoal::FromEnv)(wc),
-        (traits::DomainGoal::WellFormedTy)(ty),
+        (traits::DomainGoal::WellFormed)(wf),
+        (traits::DomainGoal::FromEnv)(from_env),
         (traits::DomainGoal::Normalize)(projection),
-        (traits::DomainGoal::FromEnvTy)(ty),
-        (traits::DomainGoal::RegionOutlives)(predicate),
-        (traits::DomainGoal::TypeOutlives)(predicate),
     }
 }
 
diff --git a/src/librustc_traits/chalk_context.rs b/src/librustc_traits/chalk_context.rs
@@ -14,7 +14,16 @@ use rustc::infer::canonical::{
     Canonical, CanonicalVarValues, Canonicalize, QueryRegionConstraint, QueryResult,
 };
 use rustc::infer::{InferCtxt, InferOk, LateBoundRegionConversionTime};
-use rustc::traits::{DomainGoal, ExClauseFold, ExClauseLift, Goal, ProgramClause, QuantifierKind};
+use rustc::traits::{
+    WellFormed, 
+    FromEnv,
+    DomainGoal,
+    ExClauseFold,
+    ExClauseLift,
+    Goal,
+    ProgramClause,
+    QuantifierKind
+};
 use rustc::ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
 use rustc::ty::subst::Kind;
 use rustc::ty::{self, TyCtxt};
@@ -314,43 +323,42 @@ impl context::UnificationOps<ChalkArenas<'gcx>, ChalkArenas<'tcx>>
         _environment: &ty::ParamEnv<'tcx>,
         goal: &DomainGoal<'tcx>,
     ) -> Vec<ProgramClause<'tcx>> {
-        use rustc::traits::DomainGoal::*;
-        use rustc::traits::WhereClauseAtom::*;
+        use rustc::traits::WhereClause::*;
 
         match goal {
-            Holds(Implemented(_trait_predicate)) => {
+            DomainGoal::Holds(Implemented(_trait_predicate)) => {
                 // These come from:
                 //
                 // - Trait definitions (implied bounds)
                 // - Implementations of the trait itself
                 panic!()
             }
 
-            Holds(ProjectionEq(_projection_predicate)) => {
+            DomainGoal::Holds(ProjectionEq(_projection_predicate)) => {
                 // These come from:
                 panic!()
             }
 
-            WellFormed(Implemented(_trait_predicate)) => {
-                // These come from -- the trait decl.
+            DomainGoal::Holds(RegionOutlives(_region_outlives)) => {
                 panic!()
             }
 
-            WellFormed(ProjectionEq(_projection_predicate)) => panic!(),
-
-            FromEnv(Implemented(_trait_predicate)) => panic!(),
-
-            FromEnv(ProjectionEq(_projection_predicate)) => panic!(),
+            DomainGoal::Holds(TypeOutlives(_type_outlives)) => {
+                panic!()
+            }
 
-            WellFormedTy(_ty) => panic!(),
+            DomainGoal::WellFormed(WellFormed::Trait(_trait_predicate)) => {
+                // These come from -- the trait decl.
+                panic!()
+            }
 
-            FromEnvTy(_ty) => panic!(),
+            DomainGoal::WellFormed(WellFormed::Ty(_ty)) => panic!(),
 
-            RegionOutlives(_region_outlives) => panic!(),
+            DomainGoal::FromEnv(FromEnv::Trait(_trait_predicate)) => panic!(),
 
-            TypeOutlives(_type_outlives) => panic!(),
+            DomainGoal::FromEnv(FromEnv::Ty(_ty)) => panic!(),
 
-            Normalize(_) => panic!(),
+            DomainGoal::Normalize(_) => panic!(),
         }
     }
 
diff --git a/src/librustc_traits/lowering.rs b/src/librustc_traits/lowering.rs
