List(Interface) is unsupported

When compiling this schema:

@0xffffffffffffffff;

interface Crop {
  harvest @0 () -> (food: Food);
}

struct Food {
  yumminess @0: UInt8;
}

struct Field {
  crops @0: List(Crop);
}

with the command capnp compile -orust schema.capnp, I get the output:

thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Error { kind: Failed, description: "List(Interface) is unsupported" }', /checkout/src/libcore/result.rs:916:4
note: Run with `RUST_BACKTRACE=1` for a backtrace.
rust: plugin failed: exit code 101

I expect it to compile successfully. capnp compile -oc++ schema.capnp does compile successfully.

capnproto / capnpc-rust

List(Interface) is unsupported #42