error[E0277]: the trait bound `Foo: FfiConverterArc<UniFfiTag>` is not satisfied
  --> tests/ui/proc_macro_arc.rs:10:1
   |
10 | #[uniffi::export]
   | ^^^^^^^^^^^^^^^^^ the trait `FfiConverterArc<UniFfiTag>` is not implemented for `Foo`
   |
   = help: the trait `LowerReturn<UT>` is implemented for `Arc<T>`
   = note: required for `Arc<Foo>` to implement `FfiConverter<UniFfiTag>`
   = note: required for `Arc<Foo>` to implement `Lower<UniFfiTag>`
   = note: required for `Arc<Foo>` to implement `LowerReturn<UniFfiTag>`
   = note: this error originates in the attribute macro `uniffi::export` (in Nightly builds, run with -Z macro-backtrace for more info)

error[E0277]: the trait bound `child::Foo: FfiConverterArc<UniFfiTag>` is not satisfied
  --> tests/ui/proc_macro_arc.rs:20:5
   |
20 |     #[uniffi::export]
   |     ^^^^^^^^^^^^^^^^^ the trait `FfiConverterArc<UniFfiTag>` is not implemented for `child::Foo`
   |
   = help: the trait `Lift<UT>` is implemented for `Arc<T>`
   = note: required for `Arc<child::Foo>` to implement `FfiConverter<UniFfiTag>`
   = note: required for `Arc<child::Foo>` to implement `Lift<UniFfiTag>`
   = note: this error originates in the attribute macro `uniffi::export` (in Nightly builds, run with -Z macro-backtrace for more info)