custom_type!() for remote types in latest version?

[chris13524]

We upgraded to the latest commit ref (c7c4809ed0e6bb9195b58855cc7cb211eac13290) (previously e796e00ad150f8b14b61a859a2e8c6497b35074e) and it seems that custom_type!() stopped working for us:

error[E0210]: type parameter `UT` must be used as the type parameter for some local type (e.g., `MyStruct<UT>`)
  --> crates/yttrium/src/uniffi_compat.rs:25:1
   |
25 | / uniffi::custom_type!(Address, String, {
26 | |     try_lift: |val| Ok(val.parse()?),
27 | |     lower: |obj| obj.to_string(),
28 | | });
   | |__^ type parameter `UT` must be used as the type parameter for some local type
   |
   = note: implementing a foreign trait is only possible if at least one of the types for which it is implemented is local
   = note: only traits defined in the current crate can be implemented for a type parameter
   = note: this error originates in the macro `uniffi::custom_type` (in Nightly builds, run with -Z macro-backtrace for more info)

We are using the external crate's alloy::primitives::Address here, and lowering it to a string so it can be used on the Kotlin side easily as a string.

Do custom types no longer work in the latest version for remote types? Or is there possibly another reason for this error?

In our case, it would be convenient to continue lowering this to a string vs exposing a full Address type Kotlin-side requiring refactors.

[mhammond]

Is this just a "remote custom type"?