Pass around interned refs to goals and not goals

9 files changed, 88 insertions, 73 deletions

diff --git a/src/Cargo.lock b/src/Cargo.lock
index 6a9488226b1..2719587f20e 100644
--- a/src/Cargo.lock
+++ b/src/Cargo.lock
@@ -270,7 +270,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "chalk-engine"
-version = "0.7.0"
+version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "chalk-macros 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1898,7 +1898,7 @@ dependencies = [
  "backtrace 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "chalk-engine 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "chalk-engine 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "flate2 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "fmt_macros 0.0.0",
  "graphviz 0.0.0",
@@ -2434,7 +2434,7 @@ name = "rustc_traits"
 version = "0.0.0"
 dependencies = [
  "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "chalk-engine 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "chalk-engine 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "graphviz 0.0.0",
  "log 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
@@ -3195,7 +3195,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum cargo_metadata 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "2d6809b327f87369e6f3651efd2c5a96c49847a3ed2559477ecba79014751ee1"
 "checksum cc 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)" = "f159dfd43363c4d08055a07703eb7a3406b0dac4d0584d96965a3262db3c9d16"
 "checksum cfg-if 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "0c4e7bb64a8ebb0d856483e1e682ea3422f883c5f5615a90d51a2c82fe87fdd3"
-"checksum chalk-engine 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "25ce2f28f55ed544a2a3756b7acf41dd7d6f27acffb2086439950925506af7d0"
+"checksum chalk-engine 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "6749eb72e7d4355d944a99f15fbaea701b978c18c5e184a025fcde942b0c9779"
 "checksum chalk-macros 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "295635afd6853aa9f20baeb7f0204862440c0fe994c5a253d5f479dac41d047e"
 "checksum chrono 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)" = "6962c635d530328acc53ac6a955e83093fedc91c5809dfac1fa60fa470830a37"
 "checksum clap 2.32.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b957d88f4b6a63b9d70d5f454ac8011819c6efa7727858f458ab71c756ce2d3e"
diff --git a/src/librustc/Cargo.toml b/src/librustc/Cargo.toml
index 6c3b52196a3..d0ec8640ce9 100644
--- a/src/librustc/Cargo.toml
+++ b/src/librustc/Cargo.toml
@@ -31,7 +31,7 @@ syntax_pos = { path = "../libsyntax_pos" }
 backtrace = "0.3.3"
 parking_lot = "0.6"
 byteorder = { version = "1.1", features = ["i128"]}
-chalk-engine = { version = "0.7.0", default-features=false }
+chalk-engine = { version = "0.8.0", default-features=false }
 rustc_fs_util = { path = "../librustc_fs_util" }
 smallvec = { version = "0.6.5", features = ["union"] }
 
diff --git a/src/librustc/ich/impls_ty.rs b/src/librustc/ich/impls_ty.rs
index 3ff0034fbbe..d6666c8793e 100644
--- a/src/librustc/ich/impls_ty.rs
+++ b/src/librustc/ich/impls_ty.rs
@@ -1356,7 +1356,7 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for traits::Goal<'tcx> {
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
-        use traits::Goal::*;
+        use traits::GoalKind::*;
 
         mem::discriminant(self).hash_stable(hcx, hasher);
         match self {
diff --git a/src/librustc/traits/mod.rs b/src/librustc/traits/mod.rs
index 286e35c5d4e..6e4abee32c0 100644
--- a/src/librustc/traits/mod.rs
+++ b/src/librustc/traits/mod.rs
@@ -318,31 +318,33 @@ pub enum QuantifierKind {
 }
 
 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
-pub enum Goal<'tcx> {
-    Implies(Clauses<'tcx>, &'tcx Goal<'tcx>),
-    And(&'tcx Goal<'tcx>, &'tcx Goal<'tcx>),
-    Not(&'tcx Goal<'tcx>),
+pub enum GoalKind<'tcx> {
+    Implies(Clauses<'tcx>, Goal<'tcx>),
+    And(Goal<'tcx>, Goal<'tcx>),
+    Not(Goal<'tcx>),
     DomainGoal(DomainGoal<'tcx>),
-    Quantified(QuantifierKind, ty::Binder<&'tcx Goal<'tcx>>),
+    Quantified(QuantifierKind, ty::Binder<Goal<'tcx>>),
     CannotProve,
 }
 
+pub type Goal<'tcx> = &'tcx GoalKind<'tcx>;
+
 pub type Goals<'tcx> = &'tcx List<Goal<'tcx>>;
 
 impl<'tcx> DomainGoal<'tcx> {
-    pub fn into_goal(self) -> Goal<'tcx> {
-        Goal::DomainGoal(self)
+    pub fn into_goal(self) -> GoalKind<'tcx> {
+        GoalKind::DomainGoal(self)
     }
 }
 
-impl<'tcx> Goal<'tcx> {
+impl<'tcx> GoalKind<'tcx> {
     pub fn from_poly_domain_goal<'a>(
         domain_goal: PolyDomainGoal<'tcx>,
         tcx: TyCtxt<'a, 'tcx, 'tcx>,
-    ) -> Goal<'tcx> {
+    ) -> GoalKind<'tcx> {
         match domain_goal.no_late_bound_regions() {
             Some(p) => p.into_goal(),
-            None => Goal::Quantified(
+            None => GoalKind::Quantified(
                 QuantifierKind::Universal,
                 domain_goal.map_bound(|p| tcx.mk_goal(p.into_goal()))
             ),
diff --git a/src/librustc/traits/structural_impls.rs b/src/librustc/traits/structural_impls.rs
index 22e79fc2638..1524f89af29 100644
--- a/src/librustc/traits/structural_impls.rs
+++ b/src/librustc/traits/structural_impls.rs
@@ -469,7 +469,7 @@ impl fmt::Display for traits::QuantifierKind {
 
 impl<'tcx> fmt::Display for traits::Goal<'tcx> {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
-        use traits::Goal::*;
+        use traits::GoalKind::*;
 
         match self {
             Implies(hypotheses, goal) => {
@@ -598,25 +598,25 @@ CloneTypeFoldableAndLiftImpls! {
 }
 
 EnumTypeFoldableImpl! {
-    impl<'tcx> TypeFoldable<'tcx> for traits::Goal<'tcx> {
-        (traits::Goal::Implies)(hypotheses, goal),
-        (traits::Goal::And)(goal1, goal2),
-        (traits::Goal::Not)(goal),
-        (traits::Goal::DomainGoal)(domain_goal),
-        (traits::Goal::Quantified)(qkind, goal),
-        (traits::Goal::CannotProve),
+    impl<'tcx> TypeFoldable<'tcx> for traits::GoalKind<'tcx> {
+        (traits::GoalKind::Implies)(hypotheses, goal),
+        (traits::GoalKind::And)(goal1, goal2),
+        (traits::GoalKind::Not)(goal),
+        (traits::GoalKind::DomainGoal)(domain_goal),
+        (traits::GoalKind::Quantified)(qkind, goal),
+        (traits::GoalKind::CannotProve),
     }
 }
 
 EnumLiftImpl! {
-    impl<'a, 'tcx> Lift<'tcx> for traits::Goal<'a> {
-        type Lifted = traits::Goal<'tcx>;
-        (traits::Goal::Implies)(hypotheses, goal),
-        (traits::Goal::And)(goal1, goal2),
-        (traits::Goal::Not)(goal),
-        (traits::Goal::DomainGoal)(domain_goal),
-        (traits::Goal::Quantified)(kind, goal),
-        (traits::Goal::CannotProve),
+    impl<'a, 'tcx> Lift<'tcx> for traits::GoalKind<'a> {
+        type Lifted = traits::GoalKind<'tcx>;
+        (traits::GoalKind::Implies)(hypotheses, goal),
+        (traits::GoalKind::And)(goal1, goal2),
+        (traits::GoalKind::Not)(goal),
+        (traits::GoalKind::DomainGoal)(domain_goal),
+        (traits::GoalKind::Quantified)(kind, goal),
+        (traits::GoalKind::CannotProve),
     }
 }
 
@@ -633,7 +633,7 @@ impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<traits::Goal<'tcx>> {
     }
 }
 
-impl<'tcx> TypeFoldable<'tcx> for &'tcx traits::Goal<'tcx> {
+impl<'tcx> TypeFoldable<'tcx> for traits::Goal<'tcx> {
     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
         let v = (**self).fold_with(folder);
         folder.tcx().mk_goal(v)
diff --git a/src/librustc/ty/context.rs b/src/librustc/ty/context.rs
index 46ba5f5ef36..3d4ae572d0b 100644
--- a/src/librustc/ty/context.rs
+++ b/src/librustc/ty/context.rs
@@ -36,7 +36,7 @@ use mir::interpret::Allocation;
 use ty::subst::{CanonicalSubsts, Kind, Substs, Subst};
 use ty::ReprOptions;
 use traits;
-use traits::{Clause, Clauses, Goal, Goals};
+use traits::{Clause, Clauses, GoalKind, Goal, Goals};
 use ty::{self, Ty, TypeAndMut};
 use ty::{TyS, TyKind, List};
 use ty::{AdtKind, AdtDef, ClosureSubsts, GeneratorSubsts, Region, Const};
@@ -143,7 +143,8 @@ pub struct CtxtInterners<'tcx> {
     predicates: InternedSet<'tcx, List<Predicate<'tcx>>>,
     const_: InternedSet<'tcx, Const<'tcx>>,
     clauses: InternedSet<'tcx, List<Clause<'tcx>>>,
-    goals: InternedSet<'tcx, List<Goal<'tcx>>>,
+    goal: InternedSet<'tcx, GoalKind<'tcx>>,
+    goal_list: InternedSet<'tcx, List<Goal<'tcx>>>,
 }
 
 impl<'gcx: 'tcx, 'tcx> CtxtInterners<'tcx> {
@@ -159,7 +160,8 @@ impl<'gcx: 'tcx, 'tcx> CtxtInterners<'tcx> {
             predicates: Default::default(),
             const_: Default::default(),
             clauses: Default::default(),
-            goals: Default::default(),
+            goal: Default::default(),
+            goal_list: Default::default(),
         }
     }
 
@@ -1731,9 +1733,9 @@ impl<'a, 'tcx> Lift<'tcx> for Region<'a> {
     }
 }
 
-impl<'a, 'tcx> Lift<'tcx> for &'a Goal<'a> {
-    type Lifted = &'tcx Goal<'tcx>;
-    fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<&'tcx Goal<'tcx>> {
+impl<'a, 'tcx> Lift<'tcx> for Goal<'a> {
+    type Lifted = Goal<'tcx>;
+    fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Goal<'tcx>> {
         if tcx.interners.arena.in_arena(*self as *const _) {
             return Some(unsafe { mem::transmute(*self) });
         }
@@ -2304,6 +2306,12 @@ impl<'tcx> Borrow<RegionKind> for Interned<'tcx, RegionKind> {
     }
 }
 
+impl<'tcx: 'lcx, 'lcx> Borrow<GoalKind<'lcx>> for Interned<'tcx, GoalKind<'tcx>> {
+    fn borrow<'a>(&'a self) -> &'a GoalKind<'lcx> {
+        &self.0
+    }
+}
+
 impl<'tcx: 'lcx, 'lcx> Borrow<[ExistentialPredicate<'lcx>]>
     for Interned<'tcx, List<ExistentialPredicate<'tcx>>> {
     fn borrow<'a>(&'a self) -> &'a [ExistentialPredicate<'lcx>] {
@@ -2419,7 +2427,8 @@ pub fn keep_local<'tcx, T: ty::TypeFoldable<'tcx>>(x: &T) -> bool {
 
 direct_interners!('tcx,
     region: mk_region(|r: &RegionKind| r.keep_in_local_tcx()) -> RegionKind,
-    const_: mk_const(|c: &Const<'_>| keep_local(&c.ty) || keep_local(&c.val)) -> Const<'tcx>
+    const_: mk_const(|c: &Const<'_>| keep_local(&c.ty) || keep_local(&c.val)) -> Const<'tcx>,
+    goal: mk_goal(|c: &GoalKind<'_>| keep_local(c)) -> GoalKind<'tcx>
 );
 
 macro_rules! slice_interners {
@@ -2438,7 +2447,7 @@ slice_interners!(
     type_list: _intern_type_list(Ty),
     substs: _intern_substs(Kind),
     clauses: _intern_clauses(Clause),
-    goals: _intern_goals(Goal)
+    goal_list: _intern_goals(Goal)
 );
 
 // This isn't a perfect fit: CanonicalVarInfo slices are always
@@ -2818,10 +2827,6 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         iter.intern_with(|xs| self.intern_goals(xs))
     }
 
-    pub fn mk_goal(self, goal: Goal<'tcx>) -> &'tcx Goal<'_> {
-        &self.intern_goals(&[goal])[0]
-    }
-
     pub fn lint_hir<S: Into<MultiSpan>>(self,
                                         lint: &'static Lint,
                                         hir_id: HirId,
diff --git a/src/librustc_traits/Cargo.toml b/src/librustc_traits/Cargo.toml
index cd21ee601a7..16f0f11757a 100644
--- a/src/librustc_traits/Cargo.toml
+++ b/src/librustc_traits/Cargo.toml
@@ -16,5 +16,5 @@ rustc = { path = "../librustc" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
-chalk-engine = { version = "0.7.0", default-features=false }
+chalk-engine = { version = "0.8.0", default-features=false }
 smallvec = { version = "0.6.5", features = ["union"] }
diff --git a/src/librustc_traits/chalk_context.rs b/src/librustc_traits/chalk_context.rs
index 4c28df97bdf..dea3aa4372a 100644
--- a/src/librustc_traits/chalk_context.rs
+++ b/src/librustc_traits/chalk_context.rs
@@ -19,6 +19,7 @@ use rustc::traits::{
     ExClauseFold,
     ExClauseLift,
     Goal,
+    GoalKind,
     ProgramClause,
     QuantifierKind
 };
@@ -92,7 +93,7 @@ impl context::Context for ChalkArenas<'tcx> {
 
     type DomainGoal = DomainGoal<'tcx>;
 
-    type BindersGoal = ty::Binder<&'tcx Goal<'tcx>>;
+    type BindersGoal = ty::Binder<Goal<'tcx>>;
 
     type Parameter = Kind<'tcx>;
 
@@ -102,14 +103,6 @@ impl context::Context for ChalkArenas<'tcx> {
 
     type UnificationResult = InferOk<'tcx, ()>;
 
-    fn into_goal(domain_goal: DomainGoal<'tcx>) -> Goal<'tcx> {
-        Goal::DomainGoal(domain_goal)
-    }
-
-    fn cannot_prove() -> Goal<'tcx> {
-        Goal::CannotProve
-    }
-
     fn goal_in_environment(
         env: &ty::ParamEnv<'tcx>,
         goal: Goal<'tcx>,
@@ -251,15 +244,23 @@ impl context::ContextOps<ChalkArenas<'gcx>> for ChalkContext<'cx, 'gcx> {
 impl context::InferenceTable<ChalkArenas<'gcx>, ChalkArenas<'tcx>>
     for ChalkInferenceContext<'cx, 'gcx, 'tcx>
 {
+    fn into_goal(&self, domain_goal: DomainGoal<'tcx>) -> Goal<'tcx> {
+        self.infcx.tcx.mk_goal(GoalKind::DomainGoal(domain_goal))
+    }
+
+    fn cannot_prove(&self) -> Goal<'tcx> {
+        self.infcx.tcx.mk_goal(GoalKind::CannotProve)
+    }
+
     fn into_hh_goal(&mut self, goal: Goal<'tcx>) -> ChalkHhGoal<'tcx> {
-        match goal {
-            Goal::Implies(..) => panic!("FIXME rust-lang-nursery/chalk#94"),
-            Goal::And(left, right) => HhGoal::And(*left, *right),
-            Goal::Not(subgoal) => HhGoal::Not(*subgoal),
-            Goal::DomainGoal(d) => HhGoal::DomainGoal(d),
-            Goal::Quantified(QuantifierKind::Universal, binder) => HhGoal::ForAll(binder),
-            Goal::Quantified(QuantifierKind::Existential, binder) => HhGoal::Exists(binder),
-            Goal::CannotProve => HhGoal::CannotProve,
+        match *goal {
+            GoalKind::Implies(..) => panic!("FIXME rust-lang-nursery/chalk#94"),
+            GoalKind::And(left, right) => HhGoal::And(left, right),
+            GoalKind::Not(subgoal) => HhGoal::Not(subgoal),
+            GoalKind::DomainGoal(d) => HhGoal::DomainGoal(d),
+            GoalKind::Quantified(QuantifierKind::Universal, binder) => HhGoal::ForAll(binder),
+            GoalKind::Quantified(QuantifierKind::Existential, binder) => HhGoal::Exists(binder),
+            GoalKind::CannotProve => HhGoal::CannotProve,
         }
     }
 
@@ -363,21 +364,21 @@ impl context::UnificationOps<ChalkArenas<'gcx>, ChalkArenas<'tcx>>
 
     fn instantiate_binders_universally(
         &mut self,
-        _arg: &ty::Binder<&'tcx Goal<'tcx>>,
+        _arg: &ty::Binder<Goal<'tcx>>,
     ) -> Goal<'tcx> {
         panic!("FIXME -- universal instantiation needs sgrif's branch")
     }
 
     fn instantiate_binders_existentially(
         &mut self,
-        arg: &ty::Binder<&'tcx Goal<'tcx>>,
+        arg: &ty::Binder<Goal<'tcx>>,
     ) -> Goal<'tcx> {
         let (value, _map) = self.infcx.replace_late_bound_regions_with_fresh_var(
             DUMMY_SP,
             LateBoundRegionConversionTime::HigherRankedType,
             arg,
         );
-        *value
+        value
     }
 
     fn debug_ex_clause(&mut self, value: &'v ChalkExClause<'tcx>) -> Box<dyn Debug + 'v> {
diff --git a/src/librustc_traits/lowering.rs b/src/librustc_traits/lowering.rs
index ad724babe49..4be348fb170 100644
--- a/src/librustc_traits/lowering.rs
+++ b/src/librustc_traits/lowering.rs
@@ -13,7 +13,14 @@ use rustc::hir::intravisit::{self, NestedVisitorMap, Visitor};
 use rustc::hir::map::definitions::DefPathData;
 use rustc::hir::{self, ImplPolarity};
 use rustc::traits::{
-    Clause, Clauses, DomainGoal, FromEnv, Goal, PolyDomainGoal, ProgramClause, WellFormed,
+    Clause,
+    Clauses,
+    DomainGoal,
+    FromEnv,
+    GoalKind,
+    PolyDomainGoal,
+    ProgramClause,
+    WellFormed,
     WhereClause,
 };
 use rustc::ty::query::Providers;
@@ -249,7 +256,7 @@ fn program_clauses_for_trait<'a, 'tcx>(
     let impl_trait: DomainGoal = trait_pred.lower();
 
     // `FromEnv(Self: Trait<P1..Pn>)`
-    let from_env_goal = impl_trait.into_from_env_goal().into_goal();
+    let from_env_goal = tcx.mk_goal(impl_trait.into_from_env_goal().into_goal());
     let hypotheses = tcx.intern_goals(&[from_env_goal]);
 
     // `Implemented(Self: Trait<P1..Pn>) :- FromEnv(Self: Trait<P1..Pn>)`
@@ -308,7 +315,7 @@ fn program_clauses_for_trait<'a, 'tcx>(
     let wf_clause = ProgramClause {
         goal: DomainGoal::WellFormed(WellFormed::Trait(trait_pred)),
         hypotheses: tcx.mk_goals(
-            wf_conditions.map(|wc| Goal::from_poly_domain_goal(wc, tcx)),
+            wf_conditions.map(|wc| tcx.mk_goal(GoalKind::from_poly_domain_goal(wc, tcx))),
         ),
     };
     let wf_clause = iter::once(Clause::ForAll(ty::Binder::dummy(wf_clause)));
@@ -352,7 +359,7 @@ fn program_clauses_for_impl<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId
         hypotheses: tcx.mk_goals(
             where_clauses
                 .into_iter()
-                .map(|wc| Goal::from_poly_domain_goal(wc, tcx)),
+                .map(|wc| tcx.mk_goal(GoalKind::from_poly_domain_goal(wc, tcx))),
         ),
     };
     tcx.intern_clauses(&[Clause::ForAll(ty::Binder::dummy(clause))])
@@ -388,7 +395,7 @@ pub fn program_clauses_for_type_def<'a, 'tcx>(
             where_clauses
                 .iter()
                 .cloned()
-                .map(|wc| Goal::from_poly_domain_goal(wc, tcx)),
+                .map(|wc| tcx.mk_goal(GoalKind::from_poly_domain_goal(wc, tcx))),
         ),
     };
 
@@ -404,7 +411,7 @@ pub fn program_clauses_for_type_def<'a, 'tcx>(
     // ```
 
     // `FromEnv(Ty<...>)`
-    let from_env_goal = DomainGoal::FromEnv(FromEnv::Ty(ty)).into_goal();
+    let from_env_goal = tcx.mk_goal(DomainGoal::FromEnv(FromEnv::Ty(ty)).into_goal());
     let hypotheses = tcx.intern_goals(&[from_env_goal]);
 
     // For each where clause `WC`:
@@ -482,7 +489,7 @@ pub fn program_clauses_for_associated_type_value<'a, 'tcx>(
         hypotheses: tcx.mk_goals(
             hypotheses
                 .into_iter()
-                .map(|wc| Goal::from_poly_domain_goal(wc, tcx)),
+                .map(|wc| tcx.mk_goal(GoalKind::from_poly_domain_goal(wc, tcx))),
         ),
     };
     tcx.intern_clauses(&[Clause::ForAll(ty::Binder::dummy(clause))])