From a932990ed48018d60cdbf3d66dfe5eb146866002 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Thu, 7 Sep 2023 17:31:35 +1000
Subject: [PATCH] Use `newtype_index` for `IntVid` and `FloatVid`.

`TyVid` already uses `newtype_index`.
---
 compiler/rustc_infer/src/infer/mod.rs |  4 +--
 compiler/rustc_type_ir/src/lib.rs     | 36 +++++++++------------------
 2 files changed, 14 insertions(+), 26 deletions(-)

diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs
index aaabf1482e2..dabebe0adc0 100644
--- a/compiler/rustc_infer/src/infer/mod.rs
+++ b/compiler/rustc_infer/src/infer/mod.rs
@@ -764,13 +764,13 @@ pub fn unsolved_variables(&self) -> Vec<Ty<'tcx>> {
             .collect();
         vars.extend(
             (0..inner.int_unification_table().len())
-                .map(|i| ty::IntVid { index: i as u32 })
+                .map(|i| ty::IntVid::from_u32(i as u32))
                 .filter(|&vid| inner.int_unification_table().probe_value(vid).is_none())
                 .map(|v| Ty::new_int_var(self.tcx, v)),
         );
         vars.extend(
             (0..inner.float_unification_table().len())
-                .map(|i| ty::FloatVid { index: i as u32 })
+                .map(|i| ty::FloatVid::from_u32(i as u32))
                 .filter(|&vid| inner.float_unification_table().probe_value(vid).is_none())
                 .map(|v| Ty::new_float_var(self.tcx, v)),
         );
diff --git a/compiler/rustc_type_ir/src/lib.rs b/compiler/rustc_type_ir/src/lib.rs
index e0abc7f04f5..e348591ebba 100644
--- a/compiler/rustc_type_ir/src/lib.rs
+++ b/compiler/rustc_type_ir/src/lib.rs
@@ -574,16 +574,16 @@ pub enum IntVarValue {
     pub struct TyVid {}
 }
 
-/// An **int**egral (`u32`, `i32`, `usize`, etc.) type **v**ariable **ID**.
-#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Encodable, Decodable)]
-pub struct IntVid {
-    pub index: u32,
+rustc_index::newtype_index! {
+    /// An **int**egral (`u32`, `i32`, `usize`, etc.) type **v**ariable **ID**.
+    #[debug_format = "?{}i"]
+    pub struct IntVid {}
 }
 
-/// An **float**ing-point (`f32` or `f64`) type **v**ariable **ID**.
-#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Encodable, Decodable)]
-pub struct FloatVid {
-    pub index: u32,
+rustc_index::newtype_index! {
+    /// A **float**ing-point (`f32` or `f64`) type **v**ariable **ID**.
+    #[debug_format = "?{}f"]
+    pub struct FloatVid {}
 }
 
 /// A placeholder for a type that hasn't been inferred yet.
@@ -645,11 +645,11 @@ impl UnifyKey for IntVid {
     type Value = Option<IntVarValue>;
     #[inline] // make this function eligible for inlining - it is quite hot.
     fn index(&self) -> u32 {
-        self.index
+        self.as_u32()
     }
     #[inline]
     fn from_index(i: u32) -> IntVid {
-        IntVid { index: i }
+        IntVid::from_u32(i)
     }
     fn tag() -> &'static str {
         "IntVid"
@@ -662,11 +662,11 @@ impl UnifyKey for FloatVid {
     type Value = Option<FloatVarValue>;
     #[inline]
     fn index(&self) -> u32 {
-        self.index
+        self.as_u32()
     }
     #[inline]
     fn from_index(i: u32) -> FloatVid {
-        FloatVid { index: i }
+        FloatVid::from_u32(i)
     }
     fn tag() -> &'static str {
         "FloatVid"
@@ -770,18 +770,6 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     }
 }
 
-impl fmt::Debug for IntVid {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "?{}i", self.index)
-    }
-}
-
-impl fmt::Debug for FloatVid {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "?{}f", self.index)
-    }
-}
-
 impl fmt::Debug for Variance {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str(match *self {