Restore const PartialEq

Author: fee1-dead

core/src/cmp.rs

@@ -224,6 +224,7 @@ use self::Ordering::*;
     append_const_msg
 )]
 #[rustc_diagnostic_item = "PartialEq"]
+#[cfg_attr(not(bootstrap), const_trait)]
 pub trait PartialEq<Rhs: ?Sized = Self> {
     /// This method tests for `self` and `other` values to be equal, and is used
     /// by `==`.
@@ -1414,12 +1415,23 @@ mod impls {
     macro_rules! partial_eq_impl {
         ($($t:ty)*) => ($(
             #[stable(feature = "rust1", since = "1.0.0")]
+            #[cfg(bootstrap)]
             impl PartialEq for $t {
                 #[inline]
                 fn eq(&self, other: &$t) -> bool { (*self) == (*other) }
                 #[inline]
                 fn ne(&self, other: &$t) -> bool { (*self) != (*other) }
             }
+
+            #[stable(feature = "rust1", since = "1.0.0")]
+            #[rustc_const_unstable(feature = "const_cmp", issue = "92391")]
+            #[cfg(not(bootstrap))]
+            impl const PartialEq for $t {
+                #[inline]
+                fn eq(&self, other: &$t) -> bool { (*self) == (*other) }
+                #[inline]
+                fn ne(&self, other: &$t) -> bool { (*self) != (*other) }
+            }
         )*)
     }