abi_stable::sabi_trait triggering repr_transparent_external_private_fields warning with latest nightly rustc

[zirconium-n]

After upgrading my rustc to rustc 1.65.0-nightly (2befdefdd 2022-08-06), following warning appeared and I think it should be fixed.

   |
60 | #[abi_stable::sabi_trait]
   | ^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: `#[warn(repr_transparent_external_private_fields)]` on by default
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #78586 <https://github.com/rust-lang/rust/issues/78586>
   = note: this struct contains `UnsafeIgnoredType<SyncSend>`, which contains private fields, and makes it not a breaking change to become non-zero-sized in the future.
   = note: this warning originates in the attribute macro `abi_stable::sabi_trait` (in Nightly builds, run with -Z macro-backtrace for more info)

[zirconium-n]

rust-lang/rust#78586

[afranchuk]

Note this is now also present in 1.64.0 (stable).

[jcrevier]

@rodrimati1992 To what degree does abi_stable depend on this behavior? Can this warning be fixed in a non-breaking change to stable_abi?