From b9e6bd7fe254d43a8804c8bf33db2f2d0845f894 Mon Sep 17 00:00:00 2001
From: AlexanderPortland <alexanderportland1@gmail.com>
Date: Thu, 7 Aug 2025 09:13:02 -0700
Subject: [PATCH] derive hash for placeholder automatically

---
 compiler/rustc_public/src/ty.rs | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/compiler/rustc_public/src/ty.rs b/compiler/rustc_public/src/ty.rs
index 957940ef22f6..1b5f0ed14299 100644
--- a/compiler/rustc_public/src/ty.rs
+++ b/compiler/rustc_public/src/ty.rs
@@ -249,22 +249,12 @@ pub struct BoundRegion {
 
 pub(crate) type UniverseIndex = u32;
 
-#[derive(Clone, Debug, Eq, PartialEq, Serialize)]
+#[derive(Clone, Debug, Eq, PartialEq, Hash, Serialize)]
 pub struct Placeholder<T> {
     pub universe: UniverseIndex,
     pub bound: T,
 }
 
-impl<T: std::hash::Hash> std::hash::Hash for Placeholder<T> {
-    fn hash<H>(&self, state: &mut H)
-    where
-        H: std::hash::Hasher,
-    {
-        self.universe.hash(state);
-        self.bound.hash(state);
-    }
-}
-
 #[derive(Clone, Copy, PartialEq, Eq, Hash, Serialize)]
 pub struct Span(usize);