rust-protobuf-build does not recursively import?

[beamspease]

I upgraded the rust-protobuf version used by rust-protobuf-build because cargo was getting stuck in a loop:
https://github.com/beamspease/rust-protobuf-build

However, I keep getting "enum not found by name" and similar messages for things which are imported, as if it isn't correctly recursively importing those files. I'm not sure if it's an issue with rust-protobuf (the panic is happening in codegen::gen) or rust-protobuf-build.