Remove PredicateKind

12 files changed, 38 insertions, 68 deletions

diff --git a/compiler/rustc_infer/src/traits/util.rs b/compiler/rustc_infer/src/traits/util.rs
index d9ef5d88f1c..113e2220d4d 100644
--- a/compiler/rustc_infer/src/traits/util.rs
+++ b/compiler/rustc_infer/src/traits/util.rs
@@ -9,12 +9,8 @@ pub fn anonymize_predicate<'tcx>(
     tcx: TyCtxt<'tcx>,
     pred: ty::Predicate<'tcx>,
 ) -> ty::Predicate<'tcx> {
-    match *pred.kind() {
-        ty::PredicateKind::ForAll(binder) => {
-            let new = ty::PredicateKind::ForAll(tcx.anonymize_late_bound_regions(binder));
-            tcx.reuse_or_mk_predicate(pred, new)
-        }
-    }
+    let new = tcx.anonymize_late_bound_regions(pred.kind());
+    tcx.reuse_or_mk_predicate(pred, new)
 }
 
 struct PredicateSet<'tcx> {
diff --git a/compiler/rustc_middle/src/ty/codec.rs b/compiler/rustc_middle/src/ty/codec.rs
index 9d371503e0a..987cb32d914 100644
--- a/compiler/rustc_middle/src/ty/codec.rs
+++ b/compiler/rustc_middle/src/ty/codec.rs
@@ -44,9 +44,9 @@ impl<'tcx, E: TyEncoder<'tcx>> EncodableWithShorthand<'tcx, E> for Ty<'tcx> {
 }
 
 impl<'tcx, E: TyEncoder<'tcx>> EncodableWithShorthand<'tcx, E> for ty::Predicate<'tcx> {
-    type Variant = ty::PredicateKind<'tcx>;
+    type Variant = ty::Binder<ty::PredicateAtom<'tcx>>;
     fn variant(&self) -> &Self::Variant {
-        self.kind()
+        self.kind_ref()
     }
 }
 
@@ -226,9 +226,9 @@ impl<'tcx, D: TyDecoder<'tcx>> Decodable<D> for ty::Predicate<'tcx> {
             assert!(pos >= SHORTHAND_OFFSET);
             let shorthand = pos - SHORTHAND_OFFSET;
 
-            decoder.with_position(shorthand, ty::PredicateKind::decode)
+            decoder.with_position(shorthand, ty::Binder::<ty::PredicateAtom<'tcx>>::decode)
         } else {
-            ty::PredicateKind::decode(decoder)
+            ty::Binder::<ty::PredicateAtom<'tcx>>::decode(decoder)
         }?;
         let predicate = decoder.tcx().mk_predicate(predicate_kind);
         Ok(predicate)
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index a355242f5ce..78ff8671d13 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -17,9 +17,9 @@ use crate::ty::query::{self, TyCtxtAt};
 use crate::ty::subst::{GenericArg, GenericArgKind, InternalSubsts, Subst, SubstsRef, UserSubsts};
 use crate::ty::TyKind::*;
 use crate::ty::{
-    self, AdtDef, AdtKind, BindingMode, BoundVar, CanonicalPolyFnSig, Const, ConstVid, DefIdTree,
-    ExistentialPredicate, FloatVar, FloatVid, GenericParamDefKind, InferConst, InferTy, IntVar,
-    IntVid, List, ParamConst, ParamTy, PolyFnSig, Predicate, PredicateInner, PredicateKind,
+    self, AdtDef, AdtKind, Binder, BindingMode, BoundVar, CanonicalPolyFnSig, Const, ConstVid,
+    DefIdTree, ExistentialPredicate, FloatVar, FloatVid, GenericParamDefKind, InferConst, InferTy,
+    IntVar, IntVid, List, ParamConst, ParamTy, PolyFnSig, Predicate, PredicateAtom, PredicateInner,
     ProjectionTy, Region, RegionKind, ReprOptions, TraitObjectVisitor, Ty, TyKind, TyS, TyVar,
     TyVid, TypeAndMut, Visibility,
 };
@@ -133,7 +133,7 @@ impl<'tcx> CtxtInterners<'tcx> {
     }
 
     #[inline(never)]
-    fn intern_predicate(&self, kind: PredicateKind<'tcx>) -> &'tcx PredicateInner<'tcx> {
+    fn intern_predicate(&self, kind: Binder<PredicateAtom<'tcx>>) -> &'tcx PredicateInner<'tcx> {
         self.predicate
             .intern(kind, |kind| {
                 let flags = super::flags::FlagComputation::for_predicate(kind);
@@ -1948,8 +1948,8 @@ impl<'tcx> Hash for Interned<'tcx, PredicateInner<'tcx>> {
     }
 }
 
-impl<'tcx> Borrow<PredicateKind<'tcx>> for Interned<'tcx, PredicateInner<'tcx>> {
-    fn borrow<'a>(&'a self) -> &'a PredicateKind<'tcx> {
+impl<'tcx> Borrow<Binder<PredicateAtom<'tcx>>> for Interned<'tcx, PredicateInner<'tcx>> {
+    fn borrow<'a>(&'a self) -> &'a Binder<PredicateAtom<'tcx>> {
         &self.0.kind
     }
 }
@@ -1987,12 +1987,6 @@ impl<'tcx> Borrow<Const<'tcx>> for Interned<'tcx, Const<'tcx>> {
     }
 }
 
-impl<'tcx> Borrow<PredicateKind<'tcx>> for Interned<'tcx, PredicateKind<'tcx>> {
-    fn borrow<'a>(&'a self) -> &'a PredicateKind<'tcx> {
-        &self.0
-    }
-}
-
 macro_rules! direct_interners {
     ($($name:ident: $method:ident($ty:ty),)+) => {
         $(impl<'tcx> PartialEq for Interned<'tcx, $ty> {
@@ -2091,7 +2085,7 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     #[inline]
-    pub fn mk_predicate(self, kind: PredicateKind<'tcx>) -> Predicate<'tcx> {
+    pub fn mk_predicate(self, kind: Binder<PredicateAtom<'tcx>>) -> Predicate<'tcx> {
         let inner = self.interners.intern_predicate(kind);
         Predicate { inner }
     }
@@ -2100,9 +2094,9 @@ impl<'tcx> TyCtxt<'tcx> {
     pub fn reuse_or_mk_predicate(
         self,
         pred: Predicate<'tcx>,
-        kind: PredicateKind<'tcx>,
+        kind: Binder<PredicateAtom<'tcx>>,
     ) -> Predicate<'tcx> {
-        if *pred.kind() != kind { self.mk_predicate(kind) } else { pred }
+        if pred.kind() != kind { self.mk_predicate(kind) } else { pred }
     }
 
     pub fn mk_mach_int(self, tm: ast::IntTy) -> Ty<'tcx> {
diff --git a/compiler/rustc_middle/src/ty/flags.rs b/compiler/rustc_middle/src/ty/flags.rs
index b7e045534b2..b99587fe734 100644
--- a/compiler/rustc_middle/src/ty/flags.rs
+++ b/compiler/rustc_middle/src/ty/flags.rs
@@ -22,7 +22,7 @@ impl FlagComputation {
         result
     }
 
-    pub fn for_predicate(kind: ty::PredicateKind<'_>) -> FlagComputation {
+    pub fn for_predicate(kind: ty::Binder<ty::PredicateAtom<'_>>) -> FlagComputation {
         let mut result = FlagComputation::new();
         result.add_predicate_kind(kind);
         result
@@ -204,8 +204,7 @@ impl FlagComputation {
         }
     }
 
-    fn add_predicate_kind(&mut self, kind: ty::PredicateKind<'_>) {
-        let ty::PredicateKind::ForAll(binder) = kind;
+    fn add_predicate_kind(&mut self, binder: ty::Binder<ty::PredicateAtom<'_>>) {
         self.bound_computation(binder, |computation, atom| computation.add_predicate_atom(atom));
     }
 
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index 97f8cc0a239..e023195605b 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -1030,7 +1030,7 @@ impl<'tcx> GenericPredicates<'tcx> {
 
 #[derive(Debug)]
 crate struct PredicateInner<'tcx> {
-    kind: PredicateKind<'tcx>,
+    kind: Binder<PredicateAtom<'tcx>>,
     flags: TypeFlags,
     /// See the comment for the corresponding field of [TyS].
     outer_exclusive_binder: ty::DebruijnIndex,
@@ -1061,7 +1061,12 @@ impl<'tcx> Eq for Predicate<'tcx> {}
 
 impl<'tcx> Predicate<'tcx> {
     #[inline(always)]
-    pub fn kind(self) -> &'tcx PredicateKind<'tcx> {
+    pub fn kind(self) -> Binder<PredicateAtom<'tcx>> {
+        self.inner.kind
+    }
+
+    #[inline(always)]
+    pub fn kind_ref(&self) -> &Binder<PredicateAtom<'tcx>> {
         &self.inner.kind
     }
 
@@ -1072,7 +1077,7 @@ impl<'tcx> Predicate<'tcx> {
     ///
     /// Note that this method panics in case this predicate has unbound variables.
     pub fn skip_binders(self) -> PredicateAtom<'tcx> {
-        let &PredicateKind::ForAll(binder) = self.kind();
+        let binder = self.kind();
         binder.skip_binder()
     }
 
@@ -1083,21 +1088,21 @@ impl<'tcx> Predicate<'tcx> {
     /// Rebinding the returned atom can causes the previously bound variables
     /// to end up at the wrong binding level.
     pub fn skip_binders_unchecked(self) -> PredicateAtom<'tcx> {
-        let &PredicateKind::ForAll(binder) = self.kind();
+        let binder = self.kind();
         binder.skip_binder()
     }
 
     /// Converts this to a `Binder<PredicateAtom<'tcx>>`. If the value was an
     /// `Atom`, then it is not allowed to contain escaping bound vars.
     pub fn bound_atom(self) -> Binder<PredicateAtom<'tcx>> {
-        let &PredicateKind::ForAll(binder) = self.kind();
+        let binder = self.kind();
         binder
     }
 
     /// Allows using a `Binder<PredicateAtom<'tcx>>` even if the given predicate previously
     /// contained unbound variables by shifting these variables outwards.
     pub fn bound_atom_with_opt_escaping(self, _tcx: TyCtxt<'tcx>) -> Binder<PredicateAtom<'tcx>> {
-        let &PredicateKind::ForAll(binder) = self.kind();
+        let binder = self.kind();
         binder
     }
 }
@@ -1119,13 +1124,6 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for Predicate<'tcx> {
 
 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
 #[derive(HashStable, TypeFoldable)]
-pub enum PredicateKind<'tcx> {
-    /// `for<'a>: ...`
-    ForAll(Binder<PredicateAtom<'tcx>>),
-}
-
-#[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
-#[derive(HashStable, TypeFoldable)]
 pub enum PredicateAtom<'tcx> {
     /// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be
     /// the `Self` type of the trait reference and `A`, `B`, and `C`
@@ -1175,7 +1173,7 @@ pub enum PredicateAtom<'tcx> {
 impl<'tcx> Binder<PredicateAtom<'tcx>> {
     /// Wraps `self` with the given qualifier if this predicate has any unbound variables.
     pub fn potentially_quantified(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
-        PredicateKind::ForAll(self).to_predicate(tcx)
+        self.to_predicate(tcx)
     }
 }
 
@@ -1387,7 +1385,7 @@ pub trait ToPredicate<'tcx> {
     fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx>;
 }
 
-impl ToPredicate<'tcx> for PredicateKind<'tcx> {
+impl ToPredicate<'tcx> for Binder<PredicateAtom<'tcx>> {
     #[inline(always)]
     fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
         tcx.mk_predicate(self)
@@ -1398,7 +1396,7 @@ impl ToPredicate<'tcx> for PredicateAtom<'tcx> {
     #[inline(always)]
     fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
         debug_assert!(!self.has_escaping_bound_vars(), "escaping bound vars for {:?}", self);
-        tcx.mk_predicate(PredicateKind::ForAll(Binder::dummy(self)))
+        tcx.mk_predicate(Binder::dummy(self))
     }
 }
 
diff --git a/compiler/rustc_middle/src/ty/print/pretty.rs b/compiler/rustc_middle/src/ty/print/pretty.rs
index 33bb5454266..04bea024bd3 100644
--- a/compiler/rustc_middle/src/ty/print/pretty.rs
+++ b/compiler/rustc_middle/src/ty/print/pretty.rs
@@ -2068,7 +2068,7 @@ define_print_and_forward_display! {
     }
 
     ty::Predicate<'tcx> {
-        let ty::PredicateKind::ForAll(binder) = self.kind();
+        let binder = self.kind();
         p!(print(binder))
     }
 
diff --git a/compiler/rustc_middle/src/ty/structural_impls.rs b/compiler/rustc_middle/src/ty/structural_impls.rs
index 0e933c82c3e..f2e41c88f15 100644
--- a/compiler/rustc_middle/src/ty/structural_impls.rs
+++ b/compiler/rustc_middle/src/ty/structural_impls.rs
@@ -228,14 +228,6 @@ impl fmt::Debug for ty::Predicate<'tcx> {
     }
 }
 
-impl fmt::Debug for ty::PredicateKind<'tcx> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match *self {
-            ty::PredicateKind::ForAll(binder) => write!(f, "ForAll({:?})", binder),
-        }
-    }
-}
-
 impl fmt::Debug for ty::PredicateAtom<'tcx> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
@@ -480,15 +472,6 @@ impl<'a, 'tcx> Lift<'tcx> for ty::ExistentialProjection<'a> {
     }
 }
 
-impl<'a, 'tcx> Lift<'tcx> for ty::PredicateKind<'a> {
-    type Lifted = ty::PredicateKind<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        match self {
-            ty::PredicateKind::ForAll(binder) => tcx.lift(binder).map(ty::PredicateKind::ForAll),
-        }
-    }
-}
-
 impl<'a, 'tcx> Lift<'tcx> for ty::PredicateAtom<'a> {
     type Lifted = ty::PredicateAtom<'tcx>;
     fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
diff --git a/compiler/rustc_trait_selection/src/traits/fulfill.rs b/compiler/rustc_trait_selection/src/traits/fulfill.rs
index c783f964e14..aa7f746e52f 100644
--- a/compiler/rustc_trait_selection/src/traits/fulfill.rs
+++ b/compiler/rustc_trait_selection/src/traits/fulfill.rs
@@ -345,7 +345,7 @@ impl<'a, 'b, 'tcx> FulfillProcessor<'a, 'b, 'tcx> {
 
         let infcx = self.selcx.infcx();
 
-        let ty::PredicateKind::ForAll(binder) = *obligation.predicate.kind();
+        let binder = obligation.predicate.kind();
         if binder.skip_binder().has_escaping_bound_vars() {
             match binder.skip_binder() {
                 // Evaluation will discard candidates using the leak check.
diff --git a/compiler/rustc_traits/src/implied_outlives_bounds.rs b/compiler/rustc_traits/src/implied_outlives_bounds.rs
index adb20364ddf..0e8e15cb221 100644
--- a/compiler/rustc_traits/src/implied_outlives_bounds.rs
+++ b/compiler/rustc_traits/src/implied_outlives_bounds.rs
@@ -94,7 +94,7 @@ fn compute_implied_outlives_bounds<'tcx>(
         // region relationships.
         implied_bounds.extend(obligations.into_iter().flat_map(|obligation| {
             assert!(!obligation.has_escaping_bound_vars());
-            let ty::PredicateKind::ForAll(binder) = obligation.predicate.kind();
+            let binder = obligation.predicate.kind();
             if binder.skip_binder().has_escaping_bound_vars() {
                 vec![]
             } else {
diff --git a/compiler/rustc_ty_utils/src/ty.rs b/compiler/rustc_ty_utils/src/ty.rs
index b28cc765330..64fefd82e06 100644
--- a/compiler/rustc_ty_utils/src/ty.rs
+++ b/compiler/rustc_ty_utils/src/ty.rs
@@ -5,7 +5,7 @@ use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LOCAL_CRATE};
 use rustc_middle::hir::map as hir_map;
 use rustc_middle::ty::subst::Subst;
 use rustc_middle::ty::{
-    self, Binder, Predicate, PredicateAtom, PredicateKind, ToPredicate, Ty, TyCtxt, WithConstness,
+    self, Binder, Predicate, PredicateAtom, ToPredicate, Ty, TyCtxt, WithConstness,
 };
 use rustc_session::CrateDisambiguator;
 use rustc_span::symbol::Symbol;
@@ -379,7 +379,7 @@ fn well_formed_types_in_env<'tcx>(
         match arg.unpack() {
             GenericArgKind::Type(ty) => {
                 let binder = Binder::dummy(PredicateAtom::TypeWellFormedFromEnv(ty));
-                Some(tcx.mk_predicate(PredicateKind::ForAll(binder)))
+                Some(tcx.mk_predicate(binder))
             }
 
             // FIXME(eddyb) no WF conditions from lifetimes?
diff --git a/compiler/rustc_typeck/src/outlives/mod.rs b/compiler/rustc_typeck/src/outlives/mod.rs
index a7322711f90..c0920895b66 100644
--- a/compiler/rustc_typeck/src/outlives/mod.rs
+++ b/compiler/rustc_typeck/src/outlives/mod.rs
@@ -31,7 +31,7 @@ fn inferred_outlives_of(tcx: TyCtxt<'_>, item_def_id: DefId) -> &[(ty::Predicate
                     let mut pred: Vec<String> = predicates
                         .iter()
                         .map(|(out_pred, _)| {
-                            let ty::PredicateKind::ForAll(binder) = out_pred.kind();
+                            let binder = out_pred.kind();
                             match binder.skip_binder() {
                                 ty::PredicateAtom::RegionOutlives(p) => p.to_string(),
                                 ty::PredicateAtom::TypeOutlives(p) => p.to_string(),
diff --git a/src/tools/clippy/clippy_lints/src/needless_pass_by_value.rs b/src/tools/clippy/clippy_lints/src/needless_pass_by_value.rs
index ad50a6a0405..d2a3bd3921d 100644
--- a/src/tools/clippy/clippy_lints/src/needless_pass_by_value.rs
+++ b/src/tools/clippy/clippy_lints/src/needless_pass_by_value.rs
@@ -115,7 +115,7 @@ impl<'tcx> LateLintPass<'tcx> for NeedlessPassByValue {
             .filter(|p| !p.is_global())
             .filter_map(|obligation| {
                 // Note that we do not want to deal with qualified predicates here.
-                let ty::PredicateKind::ForAll(binder) = obligation.predicate.kind();
+                let binder = obligation.predicate.kind();
                 match binder.skip_binder() {
                     ty::PredicateAtom::Trait(pred, _) if !binder.has_escaping_bound_vars() => {
                         if pred.def_id() == sized_trait {