Fix type inference failures in PartialOrd/Ord impls

Author: sfackler

src/trait_handlers/ord/ord_enum.rs

@@ -210,7 +210,7 @@ impl TraitHandler for OrdEnumHandler {
         } else {
             let discriminant_cmp = quote! {
                 unsafe {
-                    ::core::cmp::Ord::cmp(&*<*const _>::from(self).cast::<#discriminant_type>(), &*<*const _>::from(other).cast::<#discriminant_type>())
+                    ::core::cmp::Ord::cmp(&*<*const Self>::from(self).cast::<#discriminant_type>(), &*<*const Self>::from(other).cast::<#discriminant_type>())
                 }
             };
 

src/trait_handlers/partial_ord/partial_ord_enum.rs

@@ -215,7 +215,7 @@ impl TraitHandler for PartialOrdEnumHandler {
         } else {
             let discriminant_cmp = quote! {
                 unsafe {
-                    ::core::cmp::Ord::cmp(&*<*const _>::from(self).cast::<#discriminant_type>(), &*<*const _>::from(other).cast::<#discriminant_type>())
+                    ::core::cmp::Ord::cmp(&*<*const Self>::from(self).cast::<#discriminant_type>(), &*<*const Self>::from(other).cast::<#discriminant_type>())
                 }
             };
 

tests/ord_enum.rs

@@ -630,3 +630,11 @@ fn use_partial_ord_attr_ignore() {
     assert_eq!(Ordering::Less, Enum::Tuple(1, 2).cmp(&Enum::Tuple(1, 3)));
     assert_eq!(Ordering::Equal, Enum::Tuple(2, 2).cmp(&Enum::Tuple(1, 2)));
 }
+
+struct PoisonTypeInference;
+
+impl From<&PoisonTypeInference> for *const () {
+    fn from(value: &PoisonTypeInference) -> Self {
+        value as *const PoisonTypeInference as *const ()
+    }
+}