3 files changed, 78 insertions, 24 deletions
diff --git a/src/test/ui/deriving/deriving-all-codegen.stdout b/src/test/ui/deriving/deriving-all-codegen.stdout
index 56efc2a59..92fce6888 100644
--- a/src/test/ui/deriving/deriving-all-codegen.stdout
+++ b/src/test/ui/deriving/deriving-all-codegen.stdout
@@ -46,13 +46,15 @@ impl ::core::default::Default for Empty {
 impl ::core::hash::Hash for Empty {
     fn hash<__H: ::core::hash::Hasher>(&self, state: &mut __H) -> () {}
 }
-impl ::core::marker::StructuralPartialEq for Empty {}
+#[automatically_derived]
+impl ::core::marker::StructuralPartialEq for Empty { }
 #[automatically_derived]
 impl ::core::cmp::PartialEq for Empty {
     #[inline]
     fn eq(&self, other: &Empty) -> bool { true }
 }
-impl ::core::marker::StructuralEq for Empty {}
+#[automatically_derived]
+impl ::core::marker::StructuralEq for Empty { }
 #[automatically_derived]
 impl ::core::cmp::Eq for Empty {
     #[inline]
@@ -115,7 +117,8 @@ impl ::core::hash::Hash for Point {
         ::core::hash::Hash::hash(&self.y, state)
     }
 }
-impl ::core::marker::StructuralPartialEq for Point {}
+#[automatically_derived]
+impl ::core::marker::StructuralPartialEq for Point { }
 #[automatically_derived]
 impl ::core::cmp::PartialEq for Point {
     #[inline]
@@ -123,7 +126,8 @@ impl ::core::cmp::PartialEq for Point {
         self.x == other.x && self.y == other.y
     }
 }
-impl ::core::marker::StructuralEq for Point {}
+#[automatically_derived]
+impl ::core::marker::StructuralEq for Point { }
 #[automatically_derived]
 impl ::core::cmp::Eq for Point {
     #[inline]
@@ -225,7 +229,8 @@ impl ::core::hash::Hash for Big {
         ::core::hash::Hash::hash(&self.b8, state)
     }
 }
-impl ::core::marker::StructuralPartialEq for Big {}
+#[automatically_derived]
+impl ::core::marker::StructuralPartialEq for Big { }
 #[automatically_derived]
 impl ::core::cmp::PartialEq for Big {
     #[inline]
@@ -236,7 +241,8 @@ impl ::core::cmp::PartialEq for Big {
             self.b8 == other.b8
     }
 }
-impl ::core::marker::StructuralEq for Big {}
+#[automatically_derived]
+impl ::core::marker::StructuralEq for Big { }
 #[automatically_derived]
 impl ::core::cmp::Eq for Big {
     #[inline]
@@ -345,13 +351,15 @@ impl ::core::hash::Hash for Unsized {
         ::core::hash::Hash::hash(&self.0, state)
     }
 }
-impl ::core::marker::StructuralPartialEq for Unsized {}
+#[automatically_derived]
+impl ::core::marker::StructuralPartialEq for Unsized { }
 #[automatically_derived]
 impl ::core::cmp::PartialEq for Unsized {
     #[inline]
     fn eq(&self, other: &Unsized) -> bool { self.0 == other.0 }
 }
-impl ::core::marker::StructuralEq for Unsized {}
+#[automatically_derived]
+impl ::core::marker::StructuralEq for Unsized { }
 #[automatically_derived]
 impl ::core::cmp::Eq for Unsized {
     #[inline]
@@ -410,13 +418,15 @@ impl ::core::hash::Hash for PackedCopy {
         ::core::hash::Hash::hash(&{ self.0 }, state)
     }
 }
-impl ::core::marker::StructuralPartialEq for PackedCopy {}
+#[automatically_derived]
+impl ::core::marker::StructuralPartialEq for PackedCopy { }
 #[automatically_derived]
 impl ::core::cmp::PartialEq for PackedCopy {
     #[inline]
     fn eq(&self, other: &PackedCopy) -> bool { { self.0 } == { other.0 } }
 }
-impl ::core::marker::StructuralEq for PackedCopy {}
+#[automatically_derived]
+impl ::core::marker::StructuralEq for PackedCopy { }
 #[automatically_derived]
 impl ::core::cmp::Eq for PackedCopy {
     #[inline]
@@ -479,7 +489,8 @@ impl ::core::hash::Hash for PackedNonCopy {
         ::core::hash::Hash::hash(__self_0_0, state)
     }
 }
-impl ::core::marker::StructuralPartialEq for PackedNonCopy {}
+#[automatically_derived]
+impl ::core::marker::StructuralPartialEq for PackedNonCopy { }
 #[automatically_derived]
 impl ::core::cmp::PartialEq for PackedNonCopy {
     #[inline]
@@ -489,7 +500,8 @@ impl ::core::cmp::PartialEq for PackedNonCopy {
         *__self_0_0 == *__self_1_0
     }
 }
-impl ::core::marker::StructuralEq for PackedNonCopy {}
+#[automatically_derived]
+impl ::core::marker::StructuralEq for PackedNonCopy { }
 #[automatically_derived]
 impl ::core::cmp::Eq for PackedNonCopy {
     #[inline]
@@ -540,7 +552,8 @@ impl ::core::hash::Hash for Enum0 {
         unsafe { ::core::intrinsics::unreachable() }
     }
 }
-impl ::core::marker::StructuralPartialEq for Enum0 {}
+#[automatically_derived]
+impl ::core::marker::StructuralPartialEq for Enum0 { }
 #[automatically_derived]
 impl ::core::cmp::PartialEq for Enum0 {
     #[inline]
@@ -548,7 +561,8 @@ impl ::core::cmp::PartialEq for Enum0 {
         unsafe { ::core::intrinsics::unreachable() }
     }
 }
-impl ::core::marker::StructuralEq for Enum0 {}
+#[automatically_derived]
+impl ::core::marker::StructuralEq for Enum0 { }
 #[automatically_derived]
 impl ::core::cmp::Eq for Enum0 {
     #[inline]
@@ -607,7 +621,8 @@ impl ::core::hash::Hash for Enum1 {
         }
     }
 }
-impl ::core::marker::StructuralPartialEq for Enum1 {}
+#[automatically_derived]
+impl ::core::marker::StructuralPartialEq for Enum1 { }
 #[automatically_derived]
 impl ::core::cmp::PartialEq for Enum1 {
     #[inline]
@@ -618,7 +633,8 @@ impl ::core::cmp::PartialEq for Enum1 {
         }
     }
 }
-impl ::core::marker::StructuralEq for Enum1 {}
+#[automatically_derived]
+impl ::core::marker::StructuralEq for Enum1 { }
 #[automatically_derived]
 impl ::core::cmp::Eq for Enum1 {
     #[inline]
@@ -676,13 +692,15 @@ impl ::core::default::Default for Fieldless1 {
 impl ::core::hash::Hash for Fieldless1 {
     fn hash<__H: ::core::hash::Hasher>(&self, state: &mut __H) -> () {}
 }
-impl ::core::marker::StructuralPartialEq for Fieldless1 {}
+#[automatically_derived]
+impl ::core::marker::StructuralPartialEq for Fieldless1 { }
 #[automatically_derived]
 impl ::core::cmp::PartialEq for Fieldless1 {
     #[inline]
     fn eq(&self, other: &Fieldless1) -> bool { true }
 }
-impl ::core::marker::StructuralEq for Fieldless1 {}
+#[automatically_derived]
+impl ::core::marker::StructuralEq for Fieldless1 { }
 #[automatically_derived]
 impl ::core::cmp::Eq for Fieldless1 {
     #[inline]
@@ -743,7 +761,8 @@ impl ::core::hash::Hash for Fieldless {
         ::core::hash::Hash::hash(&__self_tag, state)
     }
 }
-impl ::core::marker::StructuralPartialEq for Fieldless {}
+#[automatically_derived]
+impl ::core::marker::StructuralPartialEq for Fieldless { }
 #[automatically_derived]
 impl ::core::cmp::PartialEq for Fieldless {
     #[inline]
@@ -753,7 +772,8 @@ impl ::core::cmp::PartialEq for Fieldless {
         __self_tag == __arg1_tag
     }
 }
-impl ::core::marker::StructuralEq for Fieldless {}
+#[automatically_derived]
+impl ::core::marker::StructuralEq for Fieldless { }
 #[automatically_derived]
 impl ::core::cmp::Eq for Fieldless {
     #[inline]
@@ -840,7 +860,8 @@ impl ::core::hash::Hash for Mixed {
         }
     }
 }
-impl ::core::marker::StructuralPartialEq for Mixed {}
+#[automatically_derived]
+impl ::core::marker::StructuralPartialEq for Mixed { }
 #[automatically_derived]
 impl ::core::cmp::PartialEq for Mixed {
     #[inline]
@@ -858,7 +879,8 @@ impl ::core::cmp::PartialEq for Mixed {
             }
     }
 }
-impl ::core::marker::StructuralEq for Mixed {}
+#[automatically_derived]
+impl ::core::marker::StructuralEq for Mixed { }
 #[automatically_derived]
 impl ::core::cmp::Eq for Mixed {
     #[inline]
@@ -967,7 +989,8 @@ impl ::core::hash::Hash for Fielded {
         }
     }
 }
-impl ::core::marker::StructuralPartialEq for Fielded {}
+#[automatically_derived]
+impl ::core::marker::StructuralPartialEq for Fielded { }
 #[automatically_derived]
 impl ::core::cmp::PartialEq for Fielded {
     #[inline]
@@ -986,7 +1009,8 @@ impl ::core::cmp::PartialEq for Fielded {
             }
     }
 }
-impl ::core::marker::StructuralEq for Fielded {}
+#[automatically_derived]
+impl ::core::marker::StructuralEq for Fielded { }
 #[automatically_derived]
 impl ::core::cmp::Eq for Fielded {
     #[inline]
diff --git a/src/test/ui/deriving/deriving-default-enum.rs b/src/test/ui/deriving/deriving-default-enum.rs
index d1a81c72c..1c7a501ed 100644
--- a/src/test/ui/deriving/deriving-default-enum.rs
+++ b/src/test/ui/deriving/deriving-default-enum.rs
@@ -12,6 +12,16 @@ enum Foo {
     Beta(NotDefault),
 }
 
+// #[default] on a generic enum does not add `Default` bounds to the type params.
+#[derive(Default)]
+enum MyOption<T> {
+    #[default]
+    None,
+    #[allow(dead_code)]
+    Some(T),
+}
+
 fn main() {
     assert_eq!(Foo::default(), Foo::Alpha);
+    assert!(matches!(MyOption::<NotDefault>::default(), MyOption::None));
 }
diff --git a/src/test/ui/deriving/deriving-hash.rs b/src/test/ui/deriving/deriving-hash.rs
index 8b51370bc..16738ec4a 100644
--- a/src/test/ui/deriving/deriving-hash.rs
+++ b/src/test/ui/deriving/deriving-hash.rs
@@ -44,6 +44,17 @@ fn fake_hash<A: Hash>(v: &mut Vec<u8>, a: A) {
     a.hash(&mut FakeHasher(v));
 }
 
+struct OnlyOneByteHasher;
+impl Hasher for OnlyOneByteHasher {
+    fn finish(&self) -> u64 {
+        unreachable!()
+    }
+
+    fn write(&mut self, bytes: &[u8]) {
+        assert_eq!(bytes.len(), 1);
+    }
+}
+
 fn main() {
     let person1 = Person {
         id: 5,
@@ -73,4 +84,13 @@ fn main() {
     let mut v = vec![];
     fake_hash(&mut v, SingleVariantEnum::A(17));
     assert_eq!(vec![17], v);
+
+    // issue #39137
+    #[repr(u8)]
+    #[derive(Hash)]
+    enum E {
+        A,
+        B,
+    }
+    E::A.hash(&mut OnlyOneByteHasher);
 }