Rollup merge of rust-lang#92256 - fee1-dead:improve-selection-err, r=oli-obk

Improve selection errors for `~const` trait bounds

Author: matthiaskrgr

core/src/cmp.rs

@@ -199,9 +199,20 @@ use self::Ordering::*;
 #[stable(feature = "rust1", since = "1.0.0")]
 #[doc(alias = "==")]
 #[doc(alias = "!=")]
-#[rustc_on_unimplemented(
-    message = "can't compare `{Self}` with `{Rhs}`",
-    label = "no implementation for `{Self} == {Rhs}`"
+#[cfg_attr(
+    bootstrap,
+    rustc_on_unimplemented(
+        message = "can't compare `{Self}` with `{Rhs}`",
+        label = "no implementation for `{Self} == {Rhs}`"
+    )
+)]
+#[cfg_attr(
+    not(bootstrap),
+    rustc_on_unimplemented(
+        message = "can't compare `{Self}` with `{Rhs}`",
+        label = "no implementation for `{Self} == {Rhs}`",
+        append_const_msg,
+    )
 )]
 #[rustc_diagnostic_item = "PartialEq"]
 pub trait PartialEq<Rhs: ?Sized = Self> {
@@ -1031,9 +1042,20 @@ impl PartialOrd for Ordering {
 #[doc(alias = "<")]
 #[doc(alias = "<=")]
 #[doc(alias = ">=")]
-#[rustc_on_unimplemented(
-    message = "can't compare `{Self}` with `{Rhs}`",
-    label = "no implementation for `{Self} < {Rhs}` and `{Self} > {Rhs}`"
+#[cfg_attr(
+    bootstrap,
+    rustc_on_unimplemented(
+        message = "can't compare `{Self}` with `{Rhs}`",
+        label = "no implementation for `{Self} < {Rhs}` and `{Self} > {Rhs}`",
+    )
+)]
+#[cfg_attr(
+    not(bootstrap),
+    rustc_on_unimplemented(
+        message = "can't compare `{Self}` with `{Rhs}`",
+        label = "no implementation for `{Self} < {Rhs}` and `{Self} > {Rhs}`",
+        append_const_msg,
+    )
 )]
 #[rustc_diagnostic_item = "PartialOrd"]
 pub trait PartialOrd<Rhs: ?Sized = Self>: PartialEq<Rhs> {

core/src/ops/arith.rs

@@ -65,11 +65,36 @@
 /// ```
 #[lang = "add"]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_on_unimplemented(
-    on(all(_Self = "{integer}", Rhs = "{float}"), message = "cannot add a float to an integer",),
-    on(all(_Self = "{float}", Rhs = "{integer}"), message = "cannot add an integer to a float",),
-    message = "cannot add `{Rhs}` to `{Self}`",
-    label = "no implementation for `{Self} + {Rhs}`"
+#[cfg_attr(
+    bootstrap,
+    rustc_on_unimplemented(
+        on(
+            all(_Self = "{integer}", Rhs = "{float}"),
+            message = "cannot add a float to an integer",
+        ),
+        on(
+            all(_Self = "{float}", Rhs = "{integer}"),
+            message = "cannot add an integer to a float",
+        ),
+        message = "cannot add `{Rhs}` to `{Self}`",
+        label = "no implementation for `{Self} + {Rhs}`"
+    )
+)]
+#[cfg_attr(
+    not(bootstrap),
+    rustc_on_unimplemented(
+        on(
+            all(_Self = "{integer}", Rhs = "{float}"),
+            message = "cannot add a float to an integer",
+        ),
+        on(
+            all(_Self = "{float}", Rhs = "{integer}"),
+            message = "cannot add an integer to a float",
+        ),
+        message = "cannot add `{Rhs}` to `{Self}`",
+        label = "no implementation for `{Self} + {Rhs}`",
+        append_const_msg,
+    )
 )]
 #[doc(alias = "+")]
 pub trait Add<Rhs = Self> {