From fc60282daea83a5deff651e6c5a93dbad4437be7 Mon Sep 17 00:00:00 2001
From: Solomon Ucko <solly.ucko@gmail.com>
Date: Tue, 28 Apr 2020 22:40:18 -0400
Subject: [PATCH 1/2] impl PartialEq<Vec<B>> for &[A], &mut [A]

---
 src/liballoc/tests/vec.rs | 54 +++++++++++++++++++++++++++++++++++++++
 src/liballoc/vec.rs       |  5 ++++
 2 files changed, 59 insertions(+)

diff --git a/src/liballoc/tests/vec.rs b/src/liballoc/tests/vec.rs
index a9813a8704f30..62a252c8be2e0 100644
--- a/src/liballoc/tests/vec.rs
+++ b/src/liballoc/tests/vec.rs
@@ -1,5 +1,6 @@
 use std::borrow::Cow;
 use std::collections::TryReserveError::*;
+use std::fmt::Debug;
 use std::mem::size_of;
 use std::panic::{catch_unwind, AssertUnwindSafe};
 use std::vec::{Drain, IntoIter};
@@ -1588,3 +1589,56 @@ fn test_push_growth_strategy() {
         }
     }
 }
+
+macro_rules! generate_assert_eq_vec_and_prim {
+    ($name:ident<$B:ident>($type:ty)) => {
+        fn $name<A: PartialEq<$B> + Debug, $B: Debug>(a: Vec<A>, b: $type) {
+            assert!(a == b);
+            assert_eq!(a, b);
+        }
+    };
+}
+
+generate_assert_eq_vec_and_prim! { assert_eq_vec_and_slice  <B>(&[B])   }
+generate_assert_eq_vec_and_prim! { assert_eq_vec_and_array_3<B>([B; 3]) }
+
+#[test]
+fn partialeq_vec_and_prim() {
+    assert_eq_vec_and_slice(vec![1, 2, 3], &[1, 2, 3]);
+    assert_eq_vec_and_array_3(vec![1, 2, 3], [1, 2, 3]);
+}
+
+macro_rules! assert_partial_eq_valid {
+    ($a2:ident, $a3:ident; $b2:ident, $b3: ident) => {
+        assert!($a2 == $b2);
+        assert!($a2 != $b3);
+        assert!($a3 != $b2);
+        assert!($a3 == $b3);
+        assert_eq!($a2, $b2);
+        assert_ne!($a2, $b3);
+        assert_ne!($a3, $b2);
+        assert_eq!($a3, $b3);
+    };
+}
+
+#[test]
+fn partialeq_vec_full() {
+    let vec2: Vec<_> = vec![1, 2];
+    let vec3: Vec<_> = vec![1, 2, 3];
+    let slice2: &[_] = &[1, 2];
+    let slice3: &[_] = &[1, 2, 3];
+    let slicemut2: &[_] = &mut [1, 2];
+    let slicemut3: &[_] = &mut [1, 2, 3];
+    let array2: [_; 2] = [1, 2];
+    let array3: [_; 3] = [1, 2, 3];
+    let arrayref2: &[_; 2] = &[1, 2];
+    let arrayref3: &[_; 3] = &[1, 2, 3];
+
+    assert_partial_eq_valid!(vec2,vec3; vec2,vec3);
+    assert_partial_eq_valid!(vec2,vec3; slice2,slice3);
+    assert_partial_eq_valid!(vec2,vec3; slicemut2,slicemut3);
+    assert_partial_eq_valid!(slice2,slice3; vec2,vec3);
+    assert_partial_eq_valid!(slicemut2,slicemut3; vec2,vec3);
+    assert_partial_eq_valid!(vec2,vec3; array2,array3);
+    assert_partial_eq_valid!(vec2,vec3; arrayref2,arrayref3);
+}
diff --git a/src/liballoc/vec.rs b/src/liballoc/vec.rs
index f16cac05ea039..c886fa4092752 100644
--- a/src/liballoc/vec.rs
+++ b/src/liballoc/vec.rs
@@ -2362,6 +2362,8 @@ macro_rules! __impl_slice_eq1 {
 __impl_slice_eq1! { [] Vec<A>, Vec<B>, }
 __impl_slice_eq1! { [] Vec<A>, &[B], }
 __impl_slice_eq1! { [] Vec<A>, &mut [B], }
+__impl_slice_eq1! { [] &[A], Vec<B>, }
+__impl_slice_eq1! { [] &mut [A], Vec<B>, }
 __impl_slice_eq1! { [] Cow<'_, [A]>, Vec<B>, A: Clone }
 __impl_slice_eq1! { [] Cow<'_, [A]>, &[B], A: Clone }
 __impl_slice_eq1! { [] Cow<'_, [A]>, &mut [B], A: Clone }
@@ -2371,6 +2373,9 @@ __impl_slice_eq1! { [const N: usize] Vec<A>, &[B; N], [B; N]: LengthAtMost32 }
 // NOTE: some less important impls are omitted to reduce code bloat
 // FIXME(Centril): Reconsider this?
 //__impl_slice_eq1! { [const N: usize] Vec<A>, &mut [B; N], [B; N]: LengthAtMost32 }
+//__impl_slice_eq1! { [const N: usize] [A; N], Vec<B>, [A; N]: LengthAtMost32 }
+//__impl_slice_eq1! { [const N: usize] &[A; N], Vec<B>, [A; N]: LengthAtMost32 }
+//__impl_slice_eq1! { [const N: usize] &mut [A; N], Vec<B>, [A; N]: LengthAtMost32 }
 //__impl_slice_eq1! { [const N: usize] Cow<'a, [A]>, [B; N], [B; N]: LengthAtMost32 }
 //__impl_slice_eq1! { [const N: usize] Cow<'a, [A]>, &[B; N], [B; N]: LengthAtMost32 }
 //__impl_slice_eq1! { [const N: usize] Cow<'a, [A]>, &mut [B; N], [B; N]: LengthAtMost32 }

From 4896a06667ae8d2df4b55822f98c90e6a6965fbc Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Sat, 20 Jun 2020 16:02:21 -0700
Subject: [PATCH 2/2] Update stability attribute of new Vec PartialEq impls

---
 src/liballoc/vec.rs | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/src/liballoc/vec.rs b/src/liballoc/vec.rs
index c886fa4092752..e245204751f0b 100644
--- a/src/liballoc/vec.rs
+++ b/src/liballoc/vec.rs
@@ -2344,12 +2344,12 @@ impl<'a, T: 'a + Copy> Extend<&'a T> for Vec<T> {
 }
 
 macro_rules! __impl_slice_eq1 {
-    ([$($vars:tt)*] $lhs:ty, $rhs:ty, $($constraints:tt)*) => {
-        #[stable(feature = "rust1", since = "1.0.0")]
+    ([$($vars:tt)*] $lhs:ty, $rhs:ty $(where $ty:ty: $bound:ident)?, #[$stability:meta]) => {
+        #[$stability]
         impl<A, B, $($vars)*> PartialEq<$rhs> for $lhs
         where
             A: PartialEq<B>,
-            $($constraints)*
+            $($ty: $bound)?
         {
             #[inline]
             fn eq(&self, other: &$rhs) -> bool { self[..] == other[..] }
@@ -2359,16 +2359,16 @@ macro_rules! __impl_slice_eq1 {
     }
 }
 
-__impl_slice_eq1! { [] Vec<A>, Vec<B>, }
-__impl_slice_eq1! { [] Vec<A>, &[B], }
-__impl_slice_eq1! { [] Vec<A>, &mut [B], }
-__impl_slice_eq1! { [] &[A], Vec<B>, }
-__impl_slice_eq1! { [] &mut [A], Vec<B>, }
-__impl_slice_eq1! { [] Cow<'_, [A]>, Vec<B>, A: Clone }
-__impl_slice_eq1! { [] Cow<'_, [A]>, &[B], A: Clone }
-__impl_slice_eq1! { [] Cow<'_, [A]>, &mut [B], A: Clone }
-__impl_slice_eq1! { [const N: usize] Vec<A>, [B; N], [B; N]: LengthAtMost32 }
-__impl_slice_eq1! { [const N: usize] Vec<A>, &[B; N], [B; N]: LengthAtMost32 }
+__impl_slice_eq1! { [] Vec<A>, Vec<B>, #[stable(feature = "rust1", since = "1.0.0")] }
+__impl_slice_eq1! { [] Vec<A>, &[B], #[stable(feature = "rust1", since = "1.0.0")] }
+__impl_slice_eq1! { [] Vec<A>, &mut [B], #[stable(feature = "rust1", since = "1.0.0")] }
+__impl_slice_eq1! { [] &[A], Vec<B>, #[stable(feature = "partialeq_vec_for_ref_slice", since = "1.46.0")] }
+__impl_slice_eq1! { [] &mut [A], Vec<B>, #[stable(feature = "partialeq_vec_for_ref_slice", since = "1.46.0")] }
+__impl_slice_eq1! { [] Cow<'_, [A]>, Vec<B> where A: Clone, #[stable(feature = "rust1", since = "1.0.0")] }
+__impl_slice_eq1! { [] Cow<'_, [A]>, &[B] where A: Clone, #[stable(feature = "rust1", since = "1.0.0")] }
+__impl_slice_eq1! { [] Cow<'_, [A]>, &mut [B] where A: Clone, #[stable(feature = "rust1", since = "1.0.0")] }
+__impl_slice_eq1! { [const N: usize] Vec<A>, [B; N] where [B; N]: LengthAtMost32, #[stable(feature = "rust1", since = "1.0.0")] }
+__impl_slice_eq1! { [const N: usize] Vec<A>, &[B; N] where [B; N]: LengthAtMost32, #[stable(feature = "rust1", since = "1.0.0")] }
 
 // NOTE: some less important impls are omitted to reduce code bloat
 // FIXME(Centril): Reconsider this?