Remove TyS

6 files changed, 65 insertions, 97 deletions

diff --git a/compiler/rustc_middle/src/arena.rs b/compiler/rustc_middle/src/arena.rs
index 2cbc381a11a..3a0ddae1c63 100644
--- a/compiler/rustc_middle/src/arena.rs
+++ b/compiler/rustc_middle/src/arena.rs
@@ -1,3 +1,5 @@
+#![allow(rustc::usage_of_ty_tykind)]
+
 /// This higher-order macro declares a list of types which can be allocated by `Arena`.
 ///
 /// Specifying the `decode` modifier will add decode impls for `&T` and `&[T]` where `T` is the type
@@ -88,7 +90,7 @@ macro_rules! arena_types {
             [] hir_id_set: rustc_hir::HirIdSet,
 
             // Interned types
-            [] tys: rustc_type_ir::WithCachedTypeInfo<rustc_middle::ty::TyS<'tcx>>,
+            [] tys: rustc_type_ir::WithCachedTypeInfo<rustc_middle::ty::TyKind<'tcx>>,
             [] predicates: rustc_type_ir::WithCachedTypeInfo<rustc_middle::ty::PredicateS<'tcx>>,
             [] consts: rustc_middle::ty::ConstS<'tcx>,
 
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index e1834f1f57a..f798c0a4e22 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -1,5 +1,7 @@
 //! Type context book-keeping.
 
+#![allow(rustc::usage_of_ty_tykind)]
+
 use crate::arena::Arena;
 use crate::dep_graph::{DepGraph, DepKindStruct};
 use crate::hir::place::Place as HirPlace;
@@ -20,7 +22,7 @@ use crate::ty::{
     ClosureSizeProfileData, Const, ConstS, DefIdTree, FloatTy, FloatVar, FloatVid,
     GenericParamDefKind, InferTy, IntTy, IntVar, IntVid, List, ParamConst, ParamTy,
     PolyExistentialPredicate, PolyFnSig, Predicate, PredicateKind, PredicateS, ProjectionTy,
-    Region, RegionKind, ReprOptions, TraitObjectVisitor, Ty, TyKind, TyS, TyVar, TyVid, TypeAndMut,
+    Region, RegionKind, ReprOptions, TraitObjectVisitor, Ty, TyKind, TyVar, TyVid, TypeAndMut,
     UintTy, Visibility,
 };
 use crate::ty::{GenericArg, GenericArgKind, InternalSubsts, SubstsRef, UserSubsts};
@@ -137,7 +139,7 @@ pub struct CtxtInterners<'tcx> {
 
     // Specifically use a speedy hash algorithm for these hash sets, since
     // they're accessed quite often.
-    type_: InternedSet<'tcx, WithCachedTypeInfo<TyS<'tcx>>>,
+    type_: InternedSet<'tcx, WithCachedTypeInfo<TyKind<'tcx>>>,
     const_lists: InternedSet<'tcx, List<ty::Const<'tcx>>>,
     substs: InternedSet<'tcx, InternalSubsts<'tcx>>,
     canonical_var_infos: InternedSet<'tcx, List<CanonicalVarInfo<'tcx>>>,
@@ -194,15 +196,12 @@ impl<'tcx> CtxtInterners<'tcx> {
                     let stable_hash =
                         self.stable_hash(&flags, sess, definitions, cstore, source_span, &kind);
 
-                    let ty_struct = TyS {
-                        kind,
+                    InternedInSet(self.arena.alloc(WithCachedTypeInfo {
+                        internee: kind,
+                        stable_hash,
                         flags: flags.flags,
                         outer_exclusive_binder: flags.outer_exclusive_binder,
-                    };
-
-                    InternedInSet(
-                        self.arena.alloc(WithCachedTypeInfo { internee: ty_struct, stable_hash }),
-                    )
+                    }))
                 })
                 .0,
         ))
@@ -2058,7 +2057,7 @@ macro_rules! sty_debug_print {
                 let shards = tcx.interners.type_.lock_shards();
                 let types = shards.iter().flat_map(|shard| shard.keys());
                 for &InternedInSet(t) in types {
-                    let variant = match t.kind {
+                    let variant = match t.internee {
                         ty::Bool | ty::Char | ty::Int(..) | ty::Uint(..) |
                             ty::Float(..) | ty::Str | ty::Never => continue,
                         ty::Error(_) => /* unimportant */ continue,
@@ -2168,26 +2167,26 @@ impl<'tcx, T: 'tcx + ?Sized> IntoPointer for InternedInSet<'tcx, T> {
 }
 
 #[allow(rustc::usage_of_ty_tykind)]
-impl<'tcx> Borrow<TyKind<'tcx>> for InternedInSet<'tcx, WithCachedTypeInfo<TyS<'tcx>>> {
+impl<'tcx> Borrow<TyKind<'tcx>> for InternedInSet<'tcx, WithCachedTypeInfo<TyKind<'tcx>>> {
     fn borrow<'a>(&'a self) -> &'a TyKind<'tcx> {
-        &self.0.kind
+        &self.0.internee
     }
 }
 
-impl<'tcx> PartialEq for InternedInSet<'tcx, WithCachedTypeInfo<TyS<'tcx>>> {
-    fn eq(&self, other: &InternedInSet<'tcx, WithCachedTypeInfo<TyS<'tcx>>>) -> bool {
+impl<'tcx> PartialEq for InternedInSet<'tcx, WithCachedTypeInfo<TyKind<'tcx>>> {
+    fn eq(&self, other: &InternedInSet<'tcx, WithCachedTypeInfo<TyKind<'tcx>>>) -> bool {
         // The `Borrow` trait requires that `x.borrow() == y.borrow()` equals
         // `x == y`.
-        self.0.kind == other.0.kind
+        self.0.internee == other.0.internee
     }
 }
 
-impl<'tcx> Eq for InternedInSet<'tcx, WithCachedTypeInfo<TyS<'tcx>>> {}
+impl<'tcx> Eq for InternedInSet<'tcx, WithCachedTypeInfo<TyKind<'tcx>>> {}
 
-impl<'tcx> Hash for InternedInSet<'tcx, WithCachedTypeInfo<TyS<'tcx>>> {
+impl<'tcx> Hash for InternedInSet<'tcx, WithCachedTypeInfo<TyKind<'tcx>>> {
     fn hash<H: Hasher>(&self, s: &mut H) {
         // The `Borrow` trait requires that `x.borrow().hash(s) == x.hash(s)`.
-        self.0.kind.hash(s)
+        self.0.internee.hash(s)
     }
 }
 
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index c56e1b6e5a0..667b55088cc 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -9,6 +9,8 @@
 //!
 //! ["The `ty` module: representing types"]: https://rustc-dev-guide.rust-lang.org/ty.html
 
+#![allow(rustc::usage_of_ty_tykind)]
+
 pub use self::fold::{FallibleTypeFolder, TypeFoldable, TypeFolder, TypeSuperFoldable};
 pub use self::visit::{TypeSuperVisitable, TypeVisitable, TypeVisitor};
 pub use self::AssocItemContainer::*;
@@ -446,89 +448,24 @@ pub struct CReaderCacheKey {
     pub pos: usize,
 }
 
-/// Represents a type.
-///
-/// IMPORTANT:
-/// - This is a very "dumb" struct (with no derives and no `impls`).
-/// - Values of this type are always interned and thus unique, and are stored
-///   as an `Interned<TyS>`.
-/// - `Ty` (which contains a reference to a `Interned<TyS>`) or `Interned<TyS>`
-///   should be used everywhere instead of `TyS`. In particular, `Ty` has most
-///   of the relevant methods.
-#[derive(PartialEq, Eq, PartialOrd, Ord)]
-#[allow(rustc::usage_of_ty_tykind)]
-pub(crate) struct TyS<'tcx> {
-    /// This field shouldn't be used directly and may be removed in the future.
-    /// Use `Ty::kind()` instead.
-    kind: TyKind<'tcx>,
-
-    /// This field provides fast access to information that is also contained
-    /// in `kind`.
-    ///
-    /// This field shouldn't be used directly and may be removed in the future.
-    /// Use `Ty::flags()` instead.
-    flags: TypeFlags,
-
-    /// This field provides fast access to information that is also contained
-    /// in `kind`.
-    ///
-    /// This is a kind of confusing thing: it stores the smallest
-    /// binder such that
-    ///
-    /// (a) the binder itself captures nothing but
-    /// (b) all the late-bound things within the type are captured
-    ///     by some sub-binder.
-    ///
-    /// So, for a type without any late-bound things, like `u32`, this
-    /// will be *innermost*, because that is the innermost binder that
-    /// captures nothing. But for a type `&'D u32`, where `'D` is a
-    /// late-bound region with De Bruijn index `D`, this would be `D + 1`
-    /// -- the binder itself does not capture `D`, but `D` is captured
-    /// by an inner binder.
-    ///
-    /// We call this concept an "exclusive" binder `D` because all
-    /// De Bruijn indices within the type are contained within `0..D`
-    /// (exclusive).
-    outer_exclusive_binder: ty::DebruijnIndex,
-}
-
 /// Use this rather than `TyS`, whenever possible.
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable)]
 #[rustc_diagnostic_item = "Ty"]
 #[rustc_pass_by_value]
-pub struct Ty<'tcx>(Interned<'tcx, WithCachedTypeInfo<TyS<'tcx>>>);
+pub struct Ty<'tcx>(Interned<'tcx, WithCachedTypeInfo<TyKind<'tcx>>>);
 
 impl<'tcx> TyCtxt<'tcx> {
     /// A "bool" type used in rustc_mir_transform unit tests when we
     /// have not spun up a TyCtxt.
     pub const BOOL_TY_FOR_UNIT_TESTING: Ty<'tcx> =
         Ty(Interned::new_unchecked(&WithCachedTypeInfo {
-            internee: TyS {
-                kind: ty::Bool,
-                flags: TypeFlags::empty(),
-                outer_exclusive_binder: DebruijnIndex::from_usize(0),
-            },
+            internee: ty::Bool,
             stable_hash: Fingerprint::ZERO,
+            flags: TypeFlags::empty(),
+            outer_exclusive_binder: DebruijnIndex::from_usize(0),
         }));
 }
 
-impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for TyS<'tcx> {
-    #[inline]
-    fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
-        let TyS {
-            kind,
-
-            // The other fields just provide fast access to information that is
-            // also contained in `kind`, so no need to hash them.
-            flags: _,
-
-            outer_exclusive_binder: _,
-        } = self;
-
-        kind.hash_stable(hcx, hasher)
-    }
-}
-
 impl ty::EarlyBoundRegion {
     /// Does this early bound region have a name? Early bound regions normally
     /// always have names except when using anonymous lifetimes (`'_`).
@@ -1030,7 +967,7 @@ impl<'tcx> Term<'tcx> {
         unsafe {
             match ptr & TAG_MASK {
                 TYPE_TAG => TermKind::Ty(Ty(Interned::new_unchecked(
-                    &*((ptr & !TAG_MASK) as *const WithCachedTypeInfo<ty::TyS<'tcx>>),
+                    &*((ptr & !TAG_MASK) as *const WithCachedTypeInfo<ty::TyKind<'tcx>>),
                 ))),
                 CONST_TAG => TermKind::Const(ty::Const(Interned::new_unchecked(
                     &*((ptr & !TAG_MASK) as *const ty::ConstS<'tcx>),
@@ -1074,7 +1011,7 @@ impl<'tcx> TermKind<'tcx> {
             TermKind::Ty(ty) => {
                 // Ensure we can use the tag bits.
                 assert_eq!(mem::align_of_val(&*ty.0.0) & TAG_MASK, 0);
-                (TYPE_TAG, ty.0.0 as *const WithCachedTypeInfo<ty::TyS<'tcx>> as usize)
+                (TYPE_TAG, ty.0.0 as *const WithCachedTypeInfo<ty::TyKind<'tcx>> as usize)
             }
             TermKind::Const(ct) => {
                 // Ensure we can use the tag bits.
@@ -2695,7 +2632,6 @@ mod size_asserts {
     use rustc_data_structures::static_assert_size;
     // tidy-alphabetical-start
     static_assert_size!(PredicateS<'_>, 48);
-    static_assert_size!(TyS<'_>, 40);
-    static_assert_size!(WithCachedTypeInfo<TyS<'_>>, 56);
+    static_assert_size!(WithCachedTypeInfo<TyKind<'_>>, 56);
     // tidy-alphabetical-end
 }
diff --git a/compiler/rustc_middle/src/ty/sty.rs b/compiler/rustc_middle/src/ty/sty.rs
index 5984686044b..a90f4f91377 100644
--- a/compiler/rustc_middle/src/ty/sty.rs
+++ b/compiler/rustc_middle/src/ty/sty.rs
@@ -1602,7 +1602,7 @@ impl<'tcx> Region<'tcx> {
 impl<'tcx> Ty<'tcx> {
     #[inline(always)]
     pub fn kind(self) -> &'tcx TyKind<'tcx> {
-        &self.0.0.kind
+        &self.0.0
     }
 
     #[inline(always)]
diff --git a/compiler/rustc_middle/src/ty/subst.rs b/compiler/rustc_middle/src/ty/subst.rs
index 13fab0068d6..89901d1575a 100644
--- a/compiler/rustc_middle/src/ty/subst.rs
+++ b/compiler/rustc_middle/src/ty/subst.rs
@@ -85,7 +85,7 @@ impl<'tcx> GenericArgKind<'tcx> {
             GenericArgKind::Type(ty) => {
                 // Ensure we can use the tag bits.
                 assert_eq!(mem::align_of_val(&*ty.0.0) & TAG_MASK, 0);
-                (TYPE_TAG, ty.0.0 as *const WithCachedTypeInfo<ty::TyS<'tcx>> as usize)
+                (TYPE_TAG, ty.0.0 as *const WithCachedTypeInfo<ty::TyKind<'tcx>> as usize)
             }
             GenericArgKind::Const(ct) => {
                 // Ensure we can use the tag bits.
@@ -163,7 +163,7 @@ impl<'tcx> GenericArg<'tcx> {
                     &*((ptr & !TAG_MASK) as *const ty::RegionKind<'tcx>),
                 ))),
                 TYPE_TAG => GenericArgKind::Type(Ty(Interned::new_unchecked(
-                    &*((ptr & !TAG_MASK) as *const WithCachedTypeInfo<ty::TyS<'tcx>>),
+                    &*((ptr & !TAG_MASK) as *const WithCachedTypeInfo<ty::TyKind<'tcx>>),
                 ))),
                 CONST_TAG => GenericArgKind::Const(ty::Const(Interned::new_unchecked(
                     &*((ptr & !TAG_MASK) as *const ty::ConstS<'tcx>),
diff --git a/compiler/rustc_type_ir/src/ty_info.rs b/compiler/rustc_type_ir/src/ty_info.rs
index 815237a06c0..4e5d424886a 100644
--- a/compiler/rustc_type_ir/src/ty_info.rs
+++ b/compiler/rustc_type_ir/src/ty_info.rs
@@ -9,9 +9,11 @@ use rustc_data_structures::{
     stable_hasher::{HashStable, StableHasher},
 };
 
+use crate::{DebruijnIndex, TypeFlags};
+
 /// A helper type that you can wrap round your own type in order to automatically
-/// cache the stable hash on creation and not recompute it whenever the stable hash
-/// of the type is computed.
+/// cache the stable hash, type flags and debruijn index on creation and
+/// not recompute it whenever the information is needed.
 /// This is only done in incremental mode. You can also opt out of caching by using
 /// StableHash::ZERO for the hash, in which case the hash gets computed each time.
 /// This is useful if you have values that you intern but never (can?) use for stable
@@ -20,6 +22,35 @@ use rustc_data_structures::{
 pub struct WithCachedTypeInfo<T> {
     pub internee: T,
     pub stable_hash: Fingerprint,
+
+    /// This field provides fast access to information that is also contained
+    /// in `kind`.
+    ///
+    /// This field shouldn't be used directly and may be removed in the future.
+    /// Use `Ty::flags()` instead.
+    pub flags: TypeFlags,
+
+    /// This field provides fast access to information that is also contained
+    /// in `kind`.
+    ///
+    /// This is a kind of confusing thing: it stores the smallest
+    /// binder such that
+    ///
+    /// (a) the binder itself captures nothing but
+    /// (b) all the late-bound things within the type are captured
+    ///     by some sub-binder.
+    ///
+    /// So, for a type without any late-bound things, like `u32`, this
+    /// will be *innermost*, because that is the innermost binder that
+    /// captures nothing. But for a type `&'D u32`, where `'D` is a
+    /// late-bound region with De Bruijn index `D`, this would be `D + 1`
+    /// -- the binder itself does not capture `D`, but `D` is captured
+    /// by an inner binder.
+    ///
+    /// We call this concept an "exclusive" binder `D` because all
+    /// De Bruijn indices within the type are contained within `0..D`
+    /// (exclusive).
+    pub outer_exclusive_binder: DebruijnIndex,
 }
 
 impl<T: PartialEq> PartialEq for WithCachedTypeInfo<T> {