use diagnostic::on_unimplemented instead

Author: mejrs

library/core/src/iter/traits/accum.rs

@@ -10,7 +10,7 @@ use crate::num::Wrapping;
 /// [`sum()`]: Iterator::sum
 /// [`FromIterator`]: iter::FromIterator
 #[stable(feature = "iter_arith_traits", since = "1.12.0")]
-#[rustc_on_unimplemented(
+#[diagnostic::on_unimplemented(
     message = "a value of type `{Self}` cannot be made by summing an iterator over elements of type `{A}`",
     label = "value of type `{Self}` cannot be made by summing a `std::iter::Iterator<Item={A}>`"
 )]
@@ -31,7 +31,7 @@ pub trait Sum<A = Self>: Sized {
 /// [`product()`]: Iterator::product
 /// [`FromIterator`]: iter::FromIterator
 #[stable(feature = "iter_arith_traits", since = "1.12.0")]
-#[rustc_on_unimplemented(
+#[diagnostic::on_unimplemented(
     message = "a value of type `{Self}` cannot be made by multiplying all elements of type `{A}` from an iterator",
     label = "value of type `{Self}` cannot be made by multiplying all elements from a `std::iter::Iterator<Item={A}>`"
 )]