Restore const PartialEq

Author: fee1-dead

library/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) }
+            }
         )*)
     }
 

tests/ui/rfcs/rfc-2632-const-trait-impl/call-generic-in-impl.rs

@@ -1,4 +1,4 @@
-// known-bug: #110395
+// check-pass
 #![feature(const_trait_impl)]
 
 #[const_trait]

tests/ui/rfcs/rfc-2632-const-trait-impl/call-generic-in-impl.stderr

@@ -1,8 +1,8 @@
 //! Basic test for calling methods on generic type parameters in `const fn`.
 
-// known-bug: #110395
+// check-pass
 
-#![feature(const_trait_impl)]
+#![feature(const_trait_impl, effects)]
 
 struct S;
 

tests/ui/rfcs/rfc-2632-const-trait-impl/call-generic-method-chain.rs

@@ -1,6 +1,6 @@
-// known-bug: #110395
+// check-pass
 
-#![feature(const_trait_impl)]
+#![feature(const_trait_impl, effects)]
 
 struct S;
 

tests/ui/rfcs/rfc-2632-const-trait-impl/call-generic-method-chain.stderr

@@ -1,10 +1,9 @@
-// FIXME(effects)
-// check-pass
 #![feature(const_trait_impl, effects)]
 
 pub const fn equals_self<T: PartialEq>(t: &T) -> bool {
     *t == *t
-    // (remove this) ~^ ERROR can't compare
+    //~^ ERROR mismatched types
+    // FIXME(effects): diagnostic
 }
 
 fn main() {}

tests/ui/rfcs/rfc-2632-const-trait-impl/call-generic-method-dup-bound.rs

@@ -0,0 +1,12 @@
+error[E0308]: mismatched types
+  --> $DIR/call-generic-method-fail.rs:4:5
+   |
+LL |     *t == *t
+   |     ^^^^^^^^ expected `host`, found `true`
+   |
+   = note: expected constant `host`
+              found constant `true`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0308`.

tests/ui/rfcs/rfc-2632-const-trait-impl/call-generic-method-dup-bound.stderr

@@ -1,8 +1,8 @@
 //! Basic test for calling methods on generic type parameters in `const fn`.
 
-// known-bug: #110395
+// check-pass
 
-#![feature(const_trait_impl)]
+#![feature(const_trait_impl, effects)]
 
 struct S;
 

tests/ui/rfcs/rfc-2632-const-trait-impl/call-generic-method-fail.rs

@@ -3,6 +3,7 @@
 #![feature(
     associated_type_bounds,
     const_trait_impl,
+    effects,
     const_cmp,
 )]
 

tests/ui/rfcs/rfc-2632-const-trait-impl/call-generic-method-fail.stderr

@@ -1,39 +1,16 @@
-error[E0635]: unknown feature `const_cmp`
-  --> $DIR/const-impl-trait.rs:6:5
+error[E0277]: can't compare `impl PartialEq + Destruct + Copy` with `impl PartialEq + Destruct + Copy`
+  --> $DIR/const-impl-trait.rs:28:17
    |
-LL |     const_cmp,
-   |     ^^^^^^^^^
-
-error: ~const can only be applied to `#[const_trait]` traits
-  --> $DIR/const-impl-trait.rs:11:30
-   |
-LL | const fn cmp(a: &impl ~const PartialEq) -> bool {
-   |                              ^^^^^^^^^
-
-error: ~const can only be applied to `#[const_trait]` traits
-  --> $DIR/const-impl-trait.rs:15:30
-   |
-LL | const fn wrap(x: impl ~const PartialEq + ~const Destruct)
-   |                              ^^^^^^^^^
-
-error: ~const can only be applied to `#[const_trait]` traits
-  --> $DIR/const-impl-trait.rs:16:20
+LL |     fn huh() -> impl ~const PartialEq + ~const Destruct + Copy {
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ no implementation for `impl PartialEq + Destruct + Copy == impl PartialEq + Destruct + Copy`
    |
-LL |     -> impl ~const PartialEq + ~const Destruct
-   |                    ^^^^^^^^^
-
-error: ~const can only be applied to `#[const_trait]` traits
-  --> $DIR/const-impl-trait.rs:23:29
+   = help: the trait `PartialEq<impl PartialEq + Destruct + Copy>` is not implemented for `impl PartialEq + Destruct + Copy`
+note: required by a bound in `Foo::{opaque#0}`
+  --> $DIR/const-impl-trait.rs:24:22
    |
 LL |     fn huh() -> impl ~const PartialEq + ~const Destruct + Copy;
-   |                             ^^^^^^^^^
-
-error: ~const can only be applied to `#[const_trait]` traits
-  --> $DIR/const-impl-trait.rs:27:29
-   |
-LL |     fn huh() -> impl ~const PartialEq + ~const Destruct + Copy {
-   |                             ^^^^^^^^^
+   |                      ^^^^^^^^^^^^^^^^ required by this bound in `Foo::{opaque#0}`
 
-error: aborting due to 6 previous errors
+error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0635`.
+For more information about this error, try `rustc --explain E0277`.

tests/ui/rfcs/rfc-2632-const-trait-impl/call-generic-method-pass.rs

@@ -1,5 +1,5 @@
-// known-bug: #110395
-#![feature(const_trait_impl, const_cmp, const_default_impls, derive_const)]
+// check-pass
+#![feature(const_trait_impl, const_cmp, const_default_impls, derive_const, effects)]
 
 pub struct A;
 

tests/ui/rfcs/rfc-2632-const-trait-impl/call-generic-method-pass.stderr

@@ -1,15 +1,9 @@
-error[E0635]: unknown feature `const_cmp`
-  --> $DIR/derive-const-use.rs:2:30
-   |
-LL | #![feature(const_trait_impl, const_cmp, const_default_impls, derive_const)]
-   |                              ^^^^^^^^^
-
 error[E0635]: unknown feature `const_default_impls`
-  --> $DIR/derive-const-use.rs:2:41
+  --> $DIR/derive-const-use.rs:3:5
    |
-LL | #![feature(const_trait_impl, const_cmp, const_default_impls, derive_const)]
-   |                                         ^^^^^^^^^^^^^^^^^^^
+LL |     const_default_impls, derive_const)]
+   |     ^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 2 previous errors
+error: aborting due to 1 previous error
 
 For more information about this error, try `rustc --explain E0635`.

tests/ui/rfcs/rfc-2632-const-trait-impl/const-impl-trait.rs

@@ -1,7 +1,7 @@
-// known-bug: #110395
+// check-pass
 
 #![feature(derive_const)]
-#![feature(const_trait_impl)]
+#![feature(const_trait_impl, effects)]
 
 #[derive_const(PartialEq)]
 pub struct Reverse<T>(T);