From 239f8dc7cb9aa4e59b31ee21c04087965eb644e6 Mon Sep 17 00:00:00 2001
From: JoJoJet <joe102000@gmail.com>
Date: Mon, 8 Aug 2022 23:49:29 -0400
Subject: [PATCH] =?UTF-8?q?undo=20an=20optimization=20=F0=9F=98=AD?=
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MIRI is buggy so we can't use fn pointers for comparisons
---
 crates/bevy_utils/src/label.rs | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/crates/bevy_utils/src/label.rs b/crates/bevy_utils/src/label.rs
index 596731bf55478..48a7bd16834a0 100644
--- a/crates/bevy_utils/src/label.rs
+++ b/crates/bevy_utils/src/label.rs
@@ -81,6 +81,7 @@ macro_rules! define_label {
         $(#[$id_attr])*
         #[derive(Clone, Copy)]
         pub struct $id_name {
+            ty: ::std::any::TypeId,
             data: u64,
             f: fn(u64, &mut ::std::fmt::Formatter) -> ::std::fmt::Result,
         }
@@ -98,7 +99,7 @@ macro_rules! define_label {
             #[inline]
             fn as_label(&self) -> $id_name {
                 let data = self.data();
-                $id_name { data, f: Self::fmt }
+                $id_name { data, ty: ::std::any::TypeId::of::<Self>(), f: Self::fmt }
             }
             /// Returns a number used to distinguish different labels of the same type.
             fn data(&self) -> u64;
@@ -128,7 +129,7 @@ macro_rules! define_label {
         impl PartialEq for $id_name {
             #[inline]
             fn eq(&self, rhs: &Self) -> bool {
-                (self.f as usize) == (rhs.f as usize) && self.data() == rhs.data()
+                self.ty == rhs.ty && self.data() == rhs.data()
             }
         }
         impl Eq for $id_name {}
@@ -136,7 +137,7 @@ macro_rules! define_label {
 
         impl std::hash::Hash for $id_name {
             fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
-                (self.f as usize).hash(state);
+                self.ty.hash(state);
                 self.data().hash(state);
             }
         }
@@ -144,10 +145,7 @@ macro_rules! define_label {
         impl $id_name {
             /// Returns true if this label was constructed from an instance of type `L`.
             pub fn is<L: $label_name>(self) -> bool {
-                // FIXME: This is potentially incorrect, due to the
-                // compiler unifying identical functions. We'll likely
-                // have to store some kind of hash of the TypeId.
-                (self.f as usize) == (<L as $label_name>::fmt as usize)
+                self.ty == ::std::any::TypeId::of::<L>()
             }
             /// Attempts to downcast this label to type `L`.
             ///