Removing the def_id field from hot ParamEnv to make it smaller

compiler/rustc_infer/src/infer/outlives/mod.rs

@@ -26,7 +26,8 @@ pub fn explicit_outlives_bounds<'tcx>(
             | ty::PredicateAtom::ClosureKind(..)
             | ty::PredicateAtom::TypeOutlives(..)
             | ty::PredicateAtom::ConstEvaluatable(..)
-            | ty::PredicateAtom::ConstEquate(..) => None,
+            | ty::PredicateAtom::ConstEquate(..)
+            | ty::PredicateAtom::TypeWellFormedFromEnv(..) => None,
             ty::PredicateAtom::RegionOutlives(ty::OutlivesPredicate(r_a, r_b)) => {
                 Some(OutlivesBound::RegionSubRegion(r_b, r_a))
             }

compiler/rustc_infer/src/traits/mod.rs

@@ -57,7 +57,7 @@ pub type TraitObligation<'tcx> = Obligation<'tcx, ty::PolyTraitPredicate<'tcx>>;
 
 // `PredicateObligation` is used a lot. Make sure it doesn't unintentionally get bigger.
 #[cfg(target_arch = "x86_64")]
-static_assert_size!(PredicateObligation<'_>, 40);
+static_assert_size!(PredicateObligation<'_>, 32);
 
 pub type Obligations<'tcx, O> = Vec<Obligation<'tcx, O>>;
 pub type PredicateObligations<'tcx> = Vec<PredicateObligation<'tcx>>;

compiler/rustc_infer/src/traits/util.rs

@@ -236,6 +236,9 @@ impl Elaborator<'tcx> {
                         .map(|predicate| predicate_obligation(predicate, None)),
                 );
             }
+            ty::PredicateAtom::TypeWellFormedFromEnv(..) => {
+                // Nothing to elaborate
+            }
         }
     }
 }

compiler/rustc_lint/src/builtin.rs

@@ -1228,7 +1228,8 @@ impl<'tcx> LateLintPass<'tcx> for TrivialConstraints {
                     ClosureKind(..) |
                     Subtype(..) |
                     ConstEvaluatable(..) |
-                    ConstEquate(..) => continue,
+                    ConstEquate(..) |
+                    TypeWellFormedFromEnv(..) => continue,
                 };
                 if predicate.is_global() {
                     cx.struct_span_lint(TRIVIAL_BOUNDS, span, |lint| {

compiler/rustc_middle/src/query/mod.rs

@@ -1399,7 +1399,7 @@ rustc_queries! {
         }
 
         query evaluate_goal(
-            goal: traits::ChalkCanonicalGoal<'tcx>
+            goal: traits::CanonicalChalkEnvironmentAndGoal<'tcx>
         ) -> Result<
             &'tcx Canonical<'tcx, canonical::QueryResponse<'tcx, ()>>,
             NoSolution

compiler/rustc_middle/src/traits/chalk.rs

@@ -6,14 +6,11 @@
 //! interned Chalk types.
 
 use rustc_middle::mir::interpret::ConstValue;
-use rustc_middle::ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
-use rustc_middle::ty::{self, AdtDef, Ty, TyCtxt};
+use rustc_middle::ty::{self, AdtDef, TyCtxt};
 
 use rustc_hir::def_id::DefId;
 use rustc_target::spec::abi::Abi;
 
-use smallvec::SmallVec;
-
 use std::cmp::Ordering;
 use std::fmt;
 use std::hash::{Hash, Hasher};
@@ -376,31 +373,10 @@ impl<'tcx> chalk_ir::interner::HasInterner for RustInterner<'tcx> {
     type Interner = Self;
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, HashStable, TypeFoldable)]
-pub enum ChalkEnvironmentClause<'tcx> {
-    /// A normal rust `ty::Predicate` in the environment.
-    Predicate(ty::Predicate<'tcx>),
-    /// A special clause in the environment that gets lowered to
-    /// `chalk_ir::FromEnv::Ty`.
-    TypeFromEnv(Ty<'tcx>),
-}
-
-impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<ChalkEnvironmentClause<'tcx>> {
-    fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
-        let v = self.iter().map(|t| t.fold_with(folder)).collect::<SmallVec<[_; 8]>>();
-        folder.tcx().intern_chalk_environment_clause_list(&v)
-    }
-
-    fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
-        self.iter().any(|t| t.visit_with(visitor))
-    }
-}
-/// We have to elaborate the environment of a chalk goal *before*
-/// canonicalization. This type wraps the predicate and the elaborated
-/// environment.
+/// A chalk environment and goal.
 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, HashStable, TypeFoldable)]
 pub struct ChalkEnvironmentAndGoal<'tcx> {
-    pub environment: &'tcx ty::List<ChalkEnvironmentClause<'tcx>>,
+    pub environment: &'tcx ty::List<ty::Predicate<'tcx>>,
     pub goal: ty::Predicate<'tcx>,
 }
 

compiler/rustc_middle/src/traits/mod.rs

@@ -26,14 +26,12 @@ use std::rc::Rc;
 
 pub use self::select::{EvaluationCache, EvaluationResult, OverflowError, SelectionCache};
 
-pub type ChalkCanonicalGoal<'tcx> = Canonical<'tcx, ChalkEnvironmentAndGoal<'tcx>>;
+pub type CanonicalChalkEnvironmentAndGoal<'tcx> = Canonical<'tcx, ChalkEnvironmentAndGoal<'tcx>>;
 
 pub use self::ImplSource::*;
 pub use self::ObligationCauseCode::*;
 
-pub use self::chalk::{
-    ChalkEnvironmentAndGoal, ChalkEnvironmentClause, RustInterner as ChalkRustInterner,
-};
+pub use self::chalk::{ChalkEnvironmentAndGoal, RustInterner as ChalkRustInterner};
 
 /// Depending on the stage of compilation, we want projection to be
 /// more or less conservative.

compiler/rustc_middle/src/ty/context.rs

@@ -91,8 +91,6 @@ pub struct CtxtInterners<'tcx> {
     projs: InternedSet<'tcx, List<ProjectionKind>>,
     place_elems: InternedSet<'tcx, List<PlaceElem<'tcx>>>,
     const_: InternedSet<'tcx, Const<'tcx>>,
-
-    chalk_environment_clause_list: InternedSet<'tcx, List<traits::ChalkEnvironmentClause<'tcx>>>,
 }
 
 impl<'tcx> CtxtInterners<'tcx> {
@@ -110,7 +108,6 @@ impl<'tcx> CtxtInterners<'tcx> {
             projs: Default::default(),
             place_elems: Default::default(),
             const_: Default::default(),
-            chalk_environment_clause_list: Default::default(),
         }
     }
 
@@ -2041,7 +2038,7 @@ direct_interners! {
 }
 
 macro_rules! slice_interners {
-    ($($field:ident: $method:ident($ty:ty)),+) => (
+    ($($field:ident: $method:ident($ty:ty)),+ $(,)?) => (
         $(impl<'tcx> TyCtxt<'tcx> {
             pub fn $method(self, v: &[$ty]) -> &'tcx List<$ty> {
                 self.interners.$field.intern_ref(v, || {
@@ -2060,8 +2057,6 @@ slice_interners!(
     predicates: _intern_predicates(Predicate<'tcx>),
     projs: _intern_projs(ProjectionKind),
     place_elems: _intern_place_elems(PlaceElem<'tcx>),
-    chalk_environment_clause_list:
-        _intern_chalk_environment_clause_list(traits::ChalkEnvironmentClause<'tcx>)
 );
 
 impl<'tcx> TyCtxt<'tcx> {
@@ -2460,13 +2455,6 @@ impl<'tcx> TyCtxt<'tcx> {
         if ts.is_empty() { List::empty() } else { self._intern_canonical_var_infos(ts) }
     }
 
-    pub fn intern_chalk_environment_clause_list(
-        self,
-        ts: &[traits::ChalkEnvironmentClause<'tcx>],
-    ) -> &'tcx List<traits::ChalkEnvironmentClause<'tcx>> {
-        if ts.is_empty() { List::empty() } else { self._intern_chalk_environment_clause_list(ts) }
-    }
-
     pub fn mk_fn_sig<I>(
         self,
         inputs: I,
@@ -2524,18 +2512,6 @@ impl<'tcx> TyCtxt<'tcx> {
         self.mk_substs(iter::once(self_ty.into()).chain(rest.iter().cloned()))
     }
 
-    pub fn mk_chalk_environment_clause_list<
-        I: InternAs<
-            [traits::ChalkEnvironmentClause<'tcx>],
-            &'tcx List<traits::ChalkEnvironmentClause<'tcx>>,
-        >,
-    >(
-        self,
-        iter: I,
-    ) -> I::Output {
-        iter.intern_with(|xs| self.intern_chalk_environment_clause_list(xs))
-    }
-
     /// Walks upwards from `id` to find a node which might change lint levels with attributes.
     /// It stops at `bound` and just returns it if reached.
     pub fn maybe_lint_level_root_bounded(self, mut id: HirId, bound: HirId) -> HirId {

compiler/rustc_middle/src/ty/flags.rs

@@ -249,6 +249,9 @@ impl FlagComputation {
                 self.add_const(expected);
                 self.add_const(found);
             }
+            ty::PredicateAtom::TypeWellFormedFromEnv(ty) => {
+                self.add_ty(ty);
+            }
         }
     }
 

compiler/rustc_middle/src/ty/mod.rs

@@ -1155,6 +1155,11 @@ pub enum PredicateAtom<'tcx> {
 
     /// Constants must be equal. The first component is the const that is expected.
     ConstEquate(&'tcx Const<'tcx>, &'tcx Const<'tcx>),
+
+    /// Represents a type found in the environment that we can use for implied bounds.
+    ///
+    /// Only used for Chalk.
+    TypeWellFormedFromEnv(Ty<'tcx>),
 }
 
 impl<'tcx> PredicateAtom<'tcx> {
@@ -1450,7 +1455,8 @@ impl<'tcx> Predicate<'tcx> {
             | PredicateAtom::ClosureKind(..)
             | PredicateAtom::TypeOutlives(..)
             | PredicateAtom::ConstEvaluatable(..)
-            | PredicateAtom::ConstEquate(..) => None,
+            | PredicateAtom::ConstEquate(..)
+            | PredicateAtom::TypeWellFormedFromEnv(..) => None,
         }
     }
 
@@ -1465,7 +1471,8 @@ impl<'tcx> Predicate<'tcx> {
             | PredicateAtom::ObjectSafe(..)
             | PredicateAtom::ClosureKind(..)
             | PredicateAtom::ConstEvaluatable(..)
-            | PredicateAtom::ConstEquate(..) => None,
+            | PredicateAtom::ConstEquate(..)
+            | PredicateAtom::TypeWellFormedFromEnv(..) => None,
         }
     }
 }
@@ -1738,11 +1745,6 @@ pub struct ParamEnv<'tcx> {
     ///
     /// Note: This is packed, use the reveal() method to access it.
     packed: CopyTaggedPtr<&'tcx List<Predicate<'tcx>>, traits::Reveal, true>,
-
-    /// If this `ParamEnv` comes from a call to `tcx.param_env(def_id)`,
-    /// register that `def_id` (useful for transitioning to the chalk trait
-    /// solver).
-    pub def_id: Option<DefId>,
 }
 
 unsafe impl rustc_data_structures::tagged_ptr::Tag for traits::Reveal {
@@ -1767,7 +1769,6 @@ impl<'tcx> fmt::Debug for ParamEnv<'tcx> {
         f.debug_struct("ParamEnv")
             .field("caller_bounds", &self.caller_bounds())
             .field("reveal", &self.reveal())
-            .field("def_id", &self.def_id)
             .finish()
     }
 }
@@ -1776,23 +1777,16 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ParamEnv<'tcx> {
     fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
         self.caller_bounds().hash_stable(hcx, hasher);
         self.reveal().hash_stable(hcx, hasher);
-        self.def_id.hash_stable(hcx, hasher);
     }
 }
 
 impl<'tcx> TypeFoldable<'tcx> for ParamEnv<'tcx> {
     fn super_fold_with<F: ty::fold::TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
-        ParamEnv::new(
-            self.caller_bounds().fold_with(folder),
-            self.reveal().fold_with(folder),
-            self.def_id.fold_with(folder),
-        )
+        ParamEnv::new(self.caller_bounds().fold_with(folder), self.reveal().fold_with(folder))
     }
 
     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
-        self.caller_bounds().visit_with(visitor)
-            || self.reveal().visit_with(visitor)
-            || self.def_id.visit_with(visitor)
+        self.caller_bounds().visit_with(visitor) || self.reveal().visit_with(visitor)
     }
 }
 
@@ -1803,7 +1797,7 @@ impl<'tcx> ParamEnv<'tcx> {
     /// type-checking.
     #[inline]
     pub fn empty() -> Self {
-        Self::new(List::empty(), Reveal::UserFacing, None)
+        Self::new(List::empty(), Reveal::UserFacing)
     }
 
     #[inline]
@@ -1825,17 +1819,13 @@ impl<'tcx> ParamEnv<'tcx> {
     /// or invoke `param_env.with_reveal_all()`.
     #[inline]
     pub fn reveal_all() -> Self {
-        Self::new(List::empty(), Reveal::All, None)
+        Self::new(List::empty(), Reveal::All)
     }
 
     /// Construct a trait environment with the given set of predicates.
     #[inline]
-    pub fn new(
-        caller_bounds: &'tcx List<Predicate<'tcx>>,
-        reveal: Reveal,
-        def_id: Option<DefId>,
-    ) -> Self {
-        ty::ParamEnv { packed: CopyTaggedPtr::new(caller_bounds, reveal), def_id }
+    pub fn new(caller_bounds: &'tcx List<Predicate<'tcx>>, reveal: Reveal) -> Self {
+        ty::ParamEnv { packed: CopyTaggedPtr::new(caller_bounds, reveal) }
     }
 
     pub fn with_user_facing(mut self) -> Self {
@@ -1857,12 +1847,12 @@ impl<'tcx> ParamEnv<'tcx> {
             return self;
         }
 
-        ParamEnv::new(tcx.normalize_opaque_types(self.caller_bounds()), Reveal::All, self.def_id)
+        ParamEnv::new(tcx.normalize_opaque_types(self.caller_bounds()), Reveal::All)
     }
 
     /// Returns this same environment but with no caller bounds.
     pub fn without_caller_bounds(self) -> Self {
-        Self::new(List::empty(), self.reveal(), self.def_id)
+        Self::new(List::empty(), self.reveal())
     }
 
     /// Creates a suitable environment in which to perform trait

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -2096,6 +2096,11 @@ define_print_and_forward_display! {
                 print(c2),
                 write("`"))
             }
+            ty::PredicateAtom::TypeWellFormedFromEnv(ty) => {
+                p!(write("the type `"),
+                print(ty),
+                write("` is found in the environment"))
+            }
         }
     }
 

compiler/rustc_middle/src/ty/structural_impls.rs

@@ -260,6 +260,9 @@ impl fmt::Debug for ty::PredicateAtom<'tcx> {
                 write!(f, "ConstEvaluatable({:?}, {:?})", def_id, substs)
             }
             ty::PredicateAtom::ConstEquate(c1, c2) => write!(f, "ConstEquate({:?}, {:?})", c1, c2),
+            ty::PredicateAtom::TypeWellFormedFromEnv(ty) => {
+                write!(f, "TypeWellFormedFromEnv({:?})", ty)
+            }
         }
     }
 }
@@ -536,6 +539,9 @@ impl<'a, 'tcx> Lift<'tcx> for ty::PredicateAtom<'a> {
             ty::PredicateAtom::ConstEquate(c1, c2) => {
                 tcx.lift(&(c1, c2)).map(|(c1, c2)| ty::PredicateAtom::ConstEquate(c1, c2))
             }
+            ty::PredicateAtom::TypeWellFormedFromEnv(ty) => {
+                tcx.lift(&ty).map(ty::PredicateAtom::TypeWellFormedFromEnv)
+            }
         }
     }
 }
@@ -551,7 +557,7 @@ impl<'a, 'tcx> Lift<'tcx> for ty::ParamEnv<'a> {
     type Lifted = ty::ParamEnv<'tcx>;
     fn lift_to_tcx(&self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
         tcx.lift(&self.caller_bounds())
-            .map(|caller_bounds| ty::ParamEnv::new(caller_bounds, self.reveal(), self.def_id))
+            .map(|caller_bounds| ty::ParamEnv::new(caller_bounds, self.reveal()))
     }
 }
 

compiler/rustc_mir/src/transform/qualify_min_const_fn.rs

@@ -30,7 +30,8 @@ pub fn is_min_const_fn(tcx: TyCtxt<'tcx>, def_id: DefId, body: &'a Body<'tcx>) -
                 | ty::PredicateAtom::WellFormed(_)
                 | ty::PredicateAtom::Projection(_)
                 | ty::PredicateAtom::ConstEvaluatable(..)
-                | ty::PredicateAtom::ConstEquate(..) => continue,
+                | ty::PredicateAtom::ConstEquate(..)
+                | ty::PredicateAtom::TypeWellFormedFromEnv(..) => continue,
                 ty::PredicateAtom::ObjectSafe(_) => {
                     bug!("object safe predicate on function: {:#?}", predicate)
                 }

compiler/rustc_trait_selection/src/opaque_types.rs

@@ -1261,7 +1261,8 @@ crate fn required_region_bounds(
                 | ty::PredicateAtom::ClosureKind(..)
                 | ty::PredicateAtom::RegionOutlives(..)
                 | ty::PredicateAtom::ConstEvaluatable(..)
-                | ty::PredicateAtom::ConstEquate(..) => None,
+                | ty::PredicateAtom::ConstEquate(..)
+                | ty::PredicateAtom::TypeWellFormedFromEnv(..) => None,
                 ty::PredicateAtom::TypeOutlives(ty::OutlivesPredicate(ref t, ref r)) => {
                     // Search for a bound of the form `erased_self_ty
                     // : 'a`, but be wary of something like `for<'a>

compiler/rustc_trait_selection/src/traits/auto_trait.rs

@@ -373,14 +373,12 @@ impl AutoTraitFinder<'tcx> {
                 computed_preds.clone().chain(user_computed_preds.iter().cloned()),
             )
             .map(|o| o.predicate);
-            new_env =
-                ty::ParamEnv::new(tcx.mk_predicates(normalized_preds), param_env.reveal(), None);
+            new_env = ty::ParamEnv::new(tcx.mk_predicates(normalized_preds), param_env.reveal());
         }
 
         let final_user_env = ty::ParamEnv::new(
             tcx.mk_predicates(user_computed_preds.into_iter()),
             user_env.reveal(),
-            None,
         );
         debug!(
             "evaluate_nested_obligations(ty={:?}, trait_did={:?}): succeeded with '{:?}' \