Implement BOXED_SLICE_INTO_ITER

Author: compiler-errors

Diff for: core/src/array/iter.rs

@@ -38,7 +38,7 @@ pub struct IntoIter<T, const N: usize> {
     alive: IndexRange,
 }
 
-// Note: the `#[rustc_skip_array_during_method_dispatch]` on `trait IntoIterator`
+// Note: the `#[rustc_skip_during_method_dispatch(array)]` on `trait IntoIterator`
 // hides this implementation from explicit `.into_iter()` calls on editions < 2021,
 // so those calls will still resolve to the slice implementation, by reference.
 #[stable(feature = "array_into_iter_impl", since = "1.53.0")]

Diff for: core/src/iter/traits/collect.rs

@@ -268,7 +268,6 @@ where
 /// }
 /// ```
 #[rustc_diagnostic_item = "IntoIterator"]
-#[rustc_skip_array_during_method_dispatch]
 #[rustc_on_unimplemented(
     on(
         _Self = "core::ops::range::RangeTo<Idx>",
@@ -312,6 +311,8 @@ where
     label = "`{Self}` is not an iterator",
     message = "`{Self}` is not an iterator"
 )]
+#[cfg_attr(bootstrap, rustc_skip_array_during_method_dispatch)]
+#[cfg_attr(not(bootstrap), rustc_skip_during_method_dispatch(array, boxed_slice))]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait IntoIterator {
     /// The type of the elements being iterated over.