From 481b282e8a123364631c0c1a702ae609c878a9a3 Mon Sep 17 00:00:00 2001
From: ibraheemdev <ibrah1440@gmail.com>
Date: Sat, 14 Aug 2021 00:02:02 -0400
Subject: [PATCH 1/2] make `BuildHasher` object safe

---
 library/core/src/hash/mod.rs            |  5 ++++-
 src/test/ui/build-hasher-object-safe.rs | 10 ++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)
 create mode 100644 src/test/ui/build-hasher-object-safe.rs

diff --git a/library/core/src/hash/mod.rs b/library/core/src/hash/mod.rs
index 9dbefe0822e36..8dec643255f64 100644
--- a/library/core/src/hash/mod.rs
+++ b/library/core/src/hash/mod.rs
@@ -520,7 +520,10 @@ pub trait BuildHasher {
     /// );
     /// ```
     #[unstable(feature = "build_hasher_simple_hash_one", issue = "86161")]
-    fn hash_one<T: Hash>(&self, x: T) -> u64 {
+    fn hash_one<T: Hash>(&self, x: T) -> u64
+    where
+        Self: Sized,
+    {
         let mut hasher = self.build_hasher();
         x.hash(&mut hasher);
         hasher.finish()
diff --git a/src/test/ui/build-hasher-object-safe.rs b/src/test/ui/build-hasher-object-safe.rs
new file mode 100644
index 0000000000000..50ec8e5e8d96e
--- /dev/null
+++ b/src/test/ui/build-hasher-object-safe.rs
@@ -0,0 +1,10 @@
+// run-pass
+
+use std::hash::BuildHasher;
+use std::collections::hash_map::{DefaultHasher, RandomState};
+
+fn ensure_object_safe(_: &dyn BuildHasher<Hasher = DefaultHasher>) {}
+
+fn main() {
+    ensure_object_safe(&RandomState::new());
+}

From 58f988fa408fb58266c1fbbc62fa29c4473d5e10 Mon Sep 17 00:00:00 2001
From: ibraheemdev <ibrah1440@gmail.com>
Date: Sun, 15 Aug 2021 13:00:25 -0400
Subject: [PATCH 2/2] move object safety test to library/core

---
 library/core/tests/hash/mod.rs          |  9 ++++++++-
 src/test/ui/build-hasher-object-safe.rs | 10 ----------
 2 files changed, 8 insertions(+), 11 deletions(-)
 delete mode 100644 src/test/ui/build-hasher-object-safe.rs

diff --git a/library/core/tests/hash/mod.rs b/library/core/tests/hash/mod.rs
index 1566d35749017..72ccdd4848a47 100644
--- a/library/core/tests/hash/mod.rs
+++ b/library/core/tests/hash/mod.rs
@@ -1,7 +1,7 @@
 mod sip;
 
 use std::default::Default;
-use std::hash::{Hash, Hasher};
+use std::hash::{BuildHasher, Hash, Hasher};
 use std::rc::Rc;
 
 struct MyHasher {
@@ -139,3 +139,10 @@ fn test_indirect_hasher() {
     }
     assert_eq!(hasher.hash, 5);
 }
+
+#[test]
+fn test_build_hasher_object_safe() {
+    use std::collections::hash_map::{DefaultHasher, RandomState};
+
+    let _: &dyn BuildHasher<Hasher = DefaultHasher> = &RandomState::new();
+}
diff --git a/src/test/ui/build-hasher-object-safe.rs b/src/test/ui/build-hasher-object-safe.rs
deleted file mode 100644
index 50ec8e5e8d96e..0000000000000
--- a/src/test/ui/build-hasher-object-safe.rs
+++ /dev/null
@@ -1,10 +0,0 @@
-// run-pass
-
-use std::hash::BuildHasher;
-use std::collections::hash_map::{DefaultHasher, RandomState};
-
-fn ensure_object_safe(_: &dyn BuildHasher<Hasher = DefaultHasher>) {}
-
-fn main() {
-    ensure_object_safe(&RandomState::new());
-}