Rollup merge of rust-lang#67101 - rust-lang:ostrich, r=Mark-Simulacrum

use `#[allow(unused_attributes)]` to paper over incr.comp problem

Paper over the problem in rust-lang#58633.

r? @Mark-Simulacrum

src/libcore/convert/mod.rs

@@ -567,6 +567,7 @@ impl<T> From<T> for T {
 ///
 /// [#64715]: https://github.com/rust-lang/rust/issues/64715
 #[stable(feature = "convert_infallible", since = "1.34.0")]
+#[allow(unused_attributes)] // FIXME(#58633): do a principled fix instead.
 #[rustc_reservation_impl = "permitting this impl would forbid us from adding \
                             `impl<T> From<!> for T` later; see rust-lang/rust#64715 for details"]
 impl<T> From<!> for T {