inline `CanonicalTyVarKind`

6 files changed, 58 insertions, 83 deletions

diff --git a/compiler/rustc_infer/src/infer/canonical/canonicalizer.rs b/compiler/rustc_infer/src/infer/canonical/canonicalizer.rs
index 3ad14dc79d5..40d3e8acaa4 100644
--- a/compiler/rustc_infer/src/infer/canonical/canonicalizer.rs
+++ b/compiler/rustc_infer/src/infer/canonical/canonicalizer.rs
@@ -17,7 +17,7 @@ use tracing::debug;
 
 use crate::infer::InferCtxt;
 use crate::infer::canonical::{
-    Canonical, CanonicalQueryInput, CanonicalTyVarKind, CanonicalVarKind, OriginalQueryValues,
+    Canonical, CanonicalQueryInput, CanonicalVarKind, OriginalQueryValues,
 };
 
 impl<'tcx> InferCtxt<'tcx> {
@@ -361,10 +361,7 @@ impl<'cx, 'tcx> TypeFolder<TyCtxt<'tcx>> for Canonicalizer<'cx, 'tcx> {
                             // FIXME: perf problem described in #55921.
                             ui = ty::UniverseIndex::ROOT;
                         }
-                        self.canonicalize_ty_var(
-                            CanonicalVarKind::Ty(CanonicalTyVarKind::General(ui)),
-                            t,
-                        )
+                        self.canonicalize_ty_var(CanonicalVarKind::Ty(ui), t)
                     }
                 }
             }
@@ -374,7 +371,7 @@ impl<'cx, 'tcx> TypeFolder<TyCtxt<'tcx>> for Canonicalizer<'cx, 'tcx> {
                 if nt != t {
                     return self.fold_ty(nt);
                 } else {
-                    self.canonicalize_ty_var(CanonicalVarKind::Ty(CanonicalTyVarKind::Int), t)
+                    self.canonicalize_ty_var(CanonicalVarKind::Int, t)
                 }
             }
             ty::Infer(ty::FloatVar(vid)) => {
@@ -382,7 +379,7 @@ impl<'cx, 'tcx> TypeFolder<TyCtxt<'tcx>> for Canonicalizer<'cx, 'tcx> {
                 if nt != t {
                     return self.fold_ty(nt);
                 } else {
-                    self.canonicalize_ty_var(CanonicalVarKind::Ty(CanonicalTyVarKind::Float), t)
+                    self.canonicalize_ty_var(CanonicalVarKind::Float, t)
                 }
             }
 
@@ -679,12 +676,10 @@ impl<'cx, 'tcx> Canonicalizer<'cx, 'tcx> {
         self.variables
             .iter()
             .map(|&kind| match kind {
-                CanonicalVarKind::Ty(CanonicalTyVarKind::Int | CanonicalTyVarKind::Float) => {
+                CanonicalVarKind::Int | CanonicalVarKind::Float => {
                     return kind;
                 }
-                CanonicalVarKind::Ty(CanonicalTyVarKind::General(u)) => {
-                    CanonicalVarKind::Ty(CanonicalTyVarKind::General(reverse_universe_map[&u]))
-                }
+                CanonicalVarKind::Ty(u) => CanonicalVarKind::Ty(reverse_universe_map[&u]),
                 CanonicalVarKind::Region(u) => CanonicalVarKind::Region(reverse_universe_map[&u]),
                 CanonicalVarKind::Const(u) => CanonicalVarKind::Const(reverse_universe_map[&u]),
                 CanonicalVarKind::PlaceholderTy(placeholder) => {
diff --git a/compiler/rustc_infer/src/infer/canonical/mod.rs b/compiler/rustc_infer/src/infer/canonical/mod.rs
index 79a2aa54ef8..223fb8419ec 100644
--- a/compiler/rustc_infer/src/infer/canonical/mod.rs
+++ b/compiler/rustc_infer/src/infer/canonical/mod.rs
@@ -108,18 +108,11 @@ impl<'tcx> InferCtxt<'tcx> {
         universe_map: impl Fn(ty::UniverseIndex) -> ty::UniverseIndex,
     ) -> GenericArg<'tcx> {
         match kind {
-            CanonicalVarKind::Ty(ty_kind) => {
-                let ty = match ty_kind {
-                    CanonicalTyVarKind::General(ui) => {
-                        self.next_ty_var_in_universe(span, universe_map(ui))
-                    }
+            CanonicalVarKind::Ty(ui) => self.next_ty_var_in_universe(span, universe_map(ui)).into(),
 
-                    CanonicalTyVarKind::Int => self.next_int_var(),
+            CanonicalVarKind::Int => self.next_int_var().into(),
 
-                    CanonicalTyVarKind::Float => self.next_float_var(),
-                };
-                ty.into()
-            }
+            CanonicalVarKind::Float => self.next_float_var().into(),
 
             CanonicalVarKind::PlaceholderTy(ty::PlaceholderType { universe, bound }) => {
                 let universe_mapped = universe_map(universe);
diff --git a/compiler/rustc_middle/src/infer/canonical.rs b/compiler/rustc_middle/src/infer/canonical.rs
index 4fe4c2dadee..153605ee7f8 100644
--- a/compiler/rustc_middle/src/infer/canonical.rs
+++ b/compiler/rustc_middle/src/infer/canonical.rs
@@ -27,7 +27,6 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::Lock;
 use rustc_macros::{HashStable, TypeFoldable, TypeVisitable};
 pub use rustc_type_ir as ir;
-pub use rustc_type_ir::CanonicalTyVarKind;
 use smallvec::SmallVec;
 
 use crate::mir::ConstraintCategory;
diff --git a/compiler/rustc_next_trait_solver/src/canonicalizer.rs b/compiler/rustc_next_trait_solver/src/canonicalizer.rs
index da05c49756f..7a8ee09650e 100644
--- a/compiler/rustc_next_trait_solver/src/canonicalizer.rs
+++ b/compiler/rustc_next_trait_solver/src/canonicalizer.rs
@@ -2,9 +2,8 @@ use rustc_type_ir::data_structures::{HashMap, ensure_sufficient_stack};
 use rustc_type_ir::inherent::*;
 use rustc_type_ir::solve::{Goal, QueryInput};
 use rustc_type_ir::{
-    self as ty, Canonical, CanonicalParamEnvCacheEntry, CanonicalTyVarKind, CanonicalVarKind,
-    Flags, InferCtxtLike, Interner, TypeFlags, TypeFoldable, TypeFolder, TypeSuperFoldable,
-    TypeVisitableExt,
+    self as ty, Canonical, CanonicalParamEnvCacheEntry, CanonicalVarKind, Flags, InferCtxtLike,
+    Interner, TypeFlags, TypeFoldable, TypeFolder, TypeSuperFoldable, TypeVisitableExt,
 };
 
 use crate::delegate::SolverDelegate;
@@ -314,14 +313,12 @@ impl<'a, D: SolverDelegate<Interner = I>, I: Interner> Canonicalizer<'a, D, I> {
                     );
 
                     match self.canonicalize_mode {
-                        CanonicalizeMode::Input { .. } => CanonicalVarKind::Ty(
-                            CanonicalTyVarKind::General(ty::UniverseIndex::ROOT),
-                        ),
+                        CanonicalizeMode::Input { .. } => {
+                            CanonicalVarKind::Ty(ty::UniverseIndex::ROOT)
+                        }
                         CanonicalizeMode::Response { .. } => {
-                            CanonicalVarKind::Ty(CanonicalTyVarKind::General(
-                                self.delegate.universe_of_ty(vid).unwrap_or_else(|| {
-                                    panic!("ty var should have been resolved: {t:?}")
-                                }),
+                            CanonicalVarKind::Ty(self.delegate.universe_of_ty(vid).unwrap_or_else(
+                                || panic!("ty var should have been resolved: {t:?}"),
                             ))
                         }
                     }
@@ -332,7 +329,7 @@ impl<'a, D: SolverDelegate<Interner = I>, I: Interner> Canonicalizer<'a, D, I> {
                         t,
                         "ty vid should have been resolved fully before canonicalization"
                     );
-                    CanonicalVarKind::Ty(CanonicalTyVarKind::Int)
+                    CanonicalVarKind::Int
                 }
                 ty::FloatVar(vid) => {
                     debug_assert_eq!(
@@ -340,7 +337,7 @@ impl<'a, D: SolverDelegate<Interner = I>, I: Interner> Canonicalizer<'a, D, I> {
                         t,
                         "ty vid should have been resolved fully before canonicalization"
                     );
-                    CanonicalVarKind::Ty(CanonicalTyVarKind::Float)
+                    CanonicalVarKind::Float
                 }
                 ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_) => {
                     panic!("fresh vars not expected in canonicalization")
diff --git a/compiler/rustc_type_ir/src/canonical.rs b/compiler/rustc_type_ir/src/canonical.rs
index de2a9186e7c..cd509ed3f72 100644
--- a/compiler/rustc_type_ir/src/canonical.rs
+++ b/compiler/rustc_type_ir/src/canonical.rs
@@ -1,5 +1,4 @@
 use std::fmt;
-use std::hash::Hash;
 use std::ops::Index;
 
 use derive_where::derive_where;
@@ -91,8 +90,14 @@ impl<I: Interner, V: fmt::Display> fmt::Display for Canonical<I, V> {
     derive(Decodable_NoContext, Encodable_NoContext, HashStable_NoContext)
 )]
 pub enum CanonicalVarKind<I: Interner> {
-    /// Some kind of type inference variable.
-    Ty(CanonicalTyVarKind),
+    /// General type variable `?T` that can be unified with arbitrary types.
+    Ty(UniverseIndex),
+
+    /// Integral type variable `?I` (that can only be unified with integral types).
+    Int,
+
+    /// Floating-point type variable `?F` (that can only be unified with float types).
+    Float,
 
     /// A "placeholder" that represents "any type".
     PlaceholderTy(I::PlaceholderTy),
@@ -117,15 +122,13 @@ impl<I: Interner> Eq for CanonicalVarKind<I> {}
 impl<I: Interner> CanonicalVarKind<I> {
     pub fn universe(self) -> UniverseIndex {
         match self {
-            CanonicalVarKind::Ty(CanonicalTyVarKind::General(ui)) => ui,
+            CanonicalVarKind::Ty(ui) => ui,
             CanonicalVarKind::Region(ui) => ui,
             CanonicalVarKind::Const(ui) => ui,
             CanonicalVarKind::PlaceholderTy(placeholder) => placeholder.universe(),
             CanonicalVarKind::PlaceholderRegion(placeholder) => placeholder.universe(),
             CanonicalVarKind::PlaceholderConst(placeholder) => placeholder.universe(),
-            CanonicalVarKind::Ty(CanonicalTyVarKind::Float | CanonicalTyVarKind::Int) => {
-                UniverseIndex::ROOT
-            }
+            CanonicalVarKind::Float | CanonicalVarKind::Int => UniverseIndex::ROOT,
         }
     }
 
@@ -135,9 +138,7 @@ impl<I: Interner> CanonicalVarKind<I> {
     /// the updated universe is not the root.
     pub fn with_updated_universe(self, ui: UniverseIndex) -> CanonicalVarKind<I> {
         match self {
-            CanonicalVarKind::Ty(CanonicalTyVarKind::General(_)) => {
-                CanonicalVarKind::Ty(CanonicalTyVarKind::General(ui))
-            }
+            CanonicalVarKind::Ty(_) => CanonicalVarKind::Ty(ui),
             CanonicalVarKind::Region(_) => CanonicalVarKind::Region(ui),
             CanonicalVarKind::Const(_) => CanonicalVarKind::Const(ui),
 
@@ -150,7 +151,7 @@ impl<I: Interner> CanonicalVarKind<I> {
             CanonicalVarKind::PlaceholderConst(placeholder) => {
                 CanonicalVarKind::PlaceholderConst(placeholder.with_updated_universe(ui))
             }
-            CanonicalVarKind::Ty(CanonicalTyVarKind::Int | CanonicalTyVarKind::Float) => {
+            CanonicalVarKind::Int | CanonicalVarKind::Float => {
                 assert_eq!(ui, UniverseIndex::ROOT);
                 self
             }
@@ -159,12 +160,14 @@ impl<I: Interner> CanonicalVarKind<I> {
 
     pub fn is_existential(self) -> bool {
         match self {
-            CanonicalVarKind::Ty(_) => true,
-            CanonicalVarKind::PlaceholderTy(_) => false,
-            CanonicalVarKind::Region(_) => true,
-            CanonicalVarKind::PlaceholderRegion(..) => false,
-            CanonicalVarKind::Const(_) => true,
-            CanonicalVarKind::PlaceholderConst(_) => false,
+            CanonicalVarKind::Ty(_)
+            | CanonicalVarKind::Int
+            | CanonicalVarKind::Float
+            | CanonicalVarKind::Region(_)
+            | CanonicalVarKind::Const(_) => true,
+            CanonicalVarKind::PlaceholderTy(_)
+            | CanonicalVarKind::PlaceholderRegion(..)
+            | CanonicalVarKind::PlaceholderConst(_) => false,
         }
     }
 
@@ -172,6 +175,8 @@ impl<I: Interner> CanonicalVarKind<I> {
         match self {
             CanonicalVarKind::Region(_) | CanonicalVarKind::PlaceholderRegion(_) => true,
             CanonicalVarKind::Ty(_)
+            | CanonicalVarKind::Int
+            | CanonicalVarKind::Float
             | CanonicalVarKind::PlaceholderTy(_)
             | CanonicalVarKind::Const(_)
             | CanonicalVarKind::PlaceholderConst(_) => false,
@@ -180,7 +185,11 @@ impl<I: Interner> CanonicalVarKind<I> {
 
     pub fn expect_placeholder_index(self) -> usize {
         match self {
-            CanonicalVarKind::Ty(_) | CanonicalVarKind::Region(_) | CanonicalVarKind::Const(_) => {
+            CanonicalVarKind::Ty(_)
+            | CanonicalVarKind::Int
+            | CanonicalVarKind::Float
+            | CanonicalVarKind::Region(_)
+            | CanonicalVarKind::Const(_) => {
                 panic!("expected placeholder: {self:?}")
             }
 
@@ -191,27 +200,6 @@ impl<I: Interner> CanonicalVarKind<I> {
     }
 }
 
-/// Rust actually has more than one category of type variables;
-/// notably, the type variables we create for literals (e.g., 22 or
-/// 22.) can only be instantiated with integral/float types (e.g.,
-/// usize or f32). In order to faithfully reproduce a type, we need to
-/// know what set of types a given type variable can be unified with.
-#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
-#[cfg_attr(
-    feature = "nightly",
-    derive(Decodable_NoContext, Encodable_NoContext, HashStable_NoContext)
-)]
-pub enum CanonicalTyVarKind {
-    /// General type variable `?T` that can be unified with arbitrary types.
-    General(UniverseIndex),
-
-    /// Integral type variable `?I` (that can only be unified with integral types).
-    Int,
-
-    /// Floating-point type variable `?F` (that can only be unified with float types).
-    Float,
-}
-
 /// A set of values corresponding to the canonical variables from some
 /// `Canonical`. You can give these values to
 /// `canonical_value.instantiate` to instantiate them into the canonical
@@ -287,7 +275,10 @@ impl<I: Interner> CanonicalVarValues<I> {
             var_values: cx.mk_args_from_iter(infos.iter().enumerate().map(
                 |(i, kind)| -> I::GenericArg {
                     match kind {
-                        CanonicalVarKind::Ty(_) | CanonicalVarKind::PlaceholderTy(_) => {
+                        CanonicalVarKind::Ty(_)
+                        | CanonicalVarKind::Int
+                        | CanonicalVarKind::Float
+                        | CanonicalVarKind::PlaceholderTy(_) => {
                             Ty::new_anon_bound(cx, ty::INNERMOST, ty::BoundVar::from_usize(i))
                                 .into()
                         }
diff --git a/tests/mir-opt/address_of.address_of_reborrow.SimplifyCfg-initial.after.mir b/tests/mir-opt/address_of.address_of_reborrow.SimplifyCfg-initial.after.mir
index 8afb6ad250e..906e5828aba 100644
--- a/tests/mir-opt/address_of.address_of_reborrow.SimplifyCfg-initial.after.mir
+++ b/tests/mir-opt/address_of.address_of_reborrow.SimplifyCfg-initial.after.mir
@@ -1,30 +1,30 @@
 // MIR for `address_of_reborrow` after SimplifyCfg-initial
 
 | User Type Annotations
-| 0: user_ty: Canonical { value: Ty(*const ^0), max_universe: U0, variables: [Ty(General(U0))] }, span: $DIR/address_of.rs:8:10: 8:18, inferred_ty: *const [i32; 10]
+| 0: user_ty: Canonical { value: Ty(*const ^0), max_universe: U0, variables: [Ty(U0)] }, span: $DIR/address_of.rs:8:10: 8:18, inferred_ty: *const [i32; 10]
 | 1: user_ty: Canonical { value: Ty(*const dyn std::marker::Send), max_universe: U0, variables: [Region(U0)] }, span: $DIR/address_of.rs:10:10: 10:25, inferred_ty: *const dyn std::marker::Send
-| 2: user_ty: Canonical { value: Ty(*const ^0), max_universe: U0, variables: [Ty(General(U0))] }, span: $DIR/address_of.rs:14:12: 14:20, inferred_ty: *const [i32; 10]
-| 3: user_ty: Canonical { value: Ty(*const ^0), max_universe: U0, variables: [Ty(General(U0))] }, span: $DIR/address_of.rs:14:12: 14:20, inferred_ty: *const [i32; 10]
+| 2: user_ty: Canonical { value: Ty(*const ^0), max_universe: U0, variables: [Ty(U0)] }, span: $DIR/address_of.rs:14:12: 14:20, inferred_ty: *const [i32; 10]
+| 3: user_ty: Canonical { value: Ty(*const ^0), max_universe: U0, variables: [Ty(U0)] }, span: $DIR/address_of.rs:14:12: 14:20, inferred_ty: *const [i32; 10]
 | 4: user_ty: Canonical { value: Ty(*const [i32; 10]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:15:12: 15:28, inferred_ty: *const [i32; 10]
 | 5: user_ty: Canonical { value: Ty(*const [i32; 10]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:15:12: 15:28, inferred_ty: *const [i32; 10]
 | 6: user_ty: Canonical { value: Ty(*const dyn std::marker::Send), max_universe: U0, variables: [Region(U0)] }, span: $DIR/address_of.rs:16:12: 16:27, inferred_ty: *const dyn std::marker::Send
 | 7: user_ty: Canonical { value: Ty(*const dyn std::marker::Send), max_universe: U0, variables: [Region(U0)] }, span: $DIR/address_of.rs:16:12: 16:27, inferred_ty: *const dyn std::marker::Send
 | 8: user_ty: Canonical { value: Ty(*const [i32]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:17:12: 17:24, inferred_ty: *const [i32]
 | 9: user_ty: Canonical { value: Ty(*const [i32]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:17:12: 17:24, inferred_ty: *const [i32]
-| 10: user_ty: Canonical { value: Ty(*const ^0), max_universe: U0, variables: [Ty(General(U0))] }, span: $DIR/address_of.rs:19:10: 19:18, inferred_ty: *const [i32; 10]
+| 10: user_ty: Canonical { value: Ty(*const ^0), max_universe: U0, variables: [Ty(U0)] }, span: $DIR/address_of.rs:19:10: 19:18, inferred_ty: *const [i32; 10]
 | 11: user_ty: Canonical { value: Ty(*const dyn std::marker::Send), max_universe: U0, variables: [Region(U0)] }, span: $DIR/address_of.rs:21:10: 21:25, inferred_ty: *const dyn std::marker::Send
-| 12: user_ty: Canonical { value: Ty(*const ^0), max_universe: U0, variables: [Ty(General(U0))] }, span: $DIR/address_of.rs:24:12: 24:20, inferred_ty: *const [i32; 10]
-| 13: user_ty: Canonical { value: Ty(*const ^0), max_universe: U0, variables: [Ty(General(U0))] }, span: $DIR/address_of.rs:24:12: 24:20, inferred_ty: *const [i32; 10]
+| 12: user_ty: Canonical { value: Ty(*const ^0), max_universe: U0, variables: [Ty(U0)] }, span: $DIR/address_of.rs:24:12: 24:20, inferred_ty: *const [i32; 10]
+| 13: user_ty: Canonical { value: Ty(*const ^0), max_universe: U0, variables: [Ty(U0)] }, span: $DIR/address_of.rs:24:12: 24:20, inferred_ty: *const [i32; 10]
 | 14: user_ty: Canonical { value: Ty(*const [i32; 10]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:25:12: 25:28, inferred_ty: *const [i32; 10]
 | 15: user_ty: Canonical { value: Ty(*const [i32; 10]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:25:12: 25:28, inferred_ty: *const [i32; 10]
 | 16: user_ty: Canonical { value: Ty(*const dyn std::marker::Send), max_universe: U0, variables: [Region(U0)] }, span: $DIR/address_of.rs:26:12: 26:27, inferred_ty: *const dyn std::marker::Send
 | 17: user_ty: Canonical { value: Ty(*const dyn std::marker::Send), max_universe: U0, variables: [Region(U0)] }, span: $DIR/address_of.rs:26:12: 26:27, inferred_ty: *const dyn std::marker::Send
 | 18: user_ty: Canonical { value: Ty(*const [i32]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:27:12: 27:24, inferred_ty: *const [i32]
 | 19: user_ty: Canonical { value: Ty(*const [i32]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:27:12: 27:24, inferred_ty: *const [i32]
-| 20: user_ty: Canonical { value: Ty(*mut ^0), max_universe: U0, variables: [Ty(General(U0))] }, span: $DIR/address_of.rs:29:10: 29:16, inferred_ty: *mut [i32; 10]
+| 20: user_ty: Canonical { value: Ty(*mut ^0), max_universe: U0, variables: [Ty(U0)] }, span: $DIR/address_of.rs:29:10: 29:16, inferred_ty: *mut [i32; 10]
 | 21: user_ty: Canonical { value: Ty(*mut dyn std::marker::Send), max_universe: U0, variables: [Region(U0)] }, span: $DIR/address_of.rs:31:10: 31:23, inferred_ty: *mut dyn std::marker::Send
-| 22: user_ty: Canonical { value: Ty(*mut ^0), max_universe: U0, variables: [Ty(General(U0))] }, span: $DIR/address_of.rs:34:12: 34:18, inferred_ty: *mut [i32; 10]
-| 23: user_ty: Canonical { value: Ty(*mut ^0), max_universe: U0, variables: [Ty(General(U0))] }, span: $DIR/address_of.rs:34:12: 34:18, inferred_ty: *mut [i32; 10]
+| 22: user_ty: Canonical { value: Ty(*mut ^0), max_universe: U0, variables: [Ty(U0)] }, span: $DIR/address_of.rs:34:12: 34:18, inferred_ty: *mut [i32; 10]
+| 23: user_ty: Canonical { value: Ty(*mut ^0), max_universe: U0, variables: [Ty(U0)] }, span: $DIR/address_of.rs:34:12: 34:18, inferred_ty: *mut [i32; 10]
 | 24: user_ty: Canonical { value: Ty(*mut [i32; 10]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:35:12: 35:26, inferred_ty: *mut [i32; 10]
 | 25: user_ty: Canonical { value: Ty(*mut [i32; 10]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:35:12: 35:26, inferred_ty: *mut [i32; 10]
 | 26: user_ty: Canonical { value: Ty(*mut dyn std::marker::Send), max_universe: U0, variables: [Region(U0)] }, span: $DIR/address_of.rs:36:12: 36:25, inferred_ty: *mut dyn std::marker::Send