This wit:

interface red {
  use self.green.{thing}

  foo: func() -> thing
}

interface green {
  type thing = s32
}

default world neptune {
  import blue: self.red
  import orange: self.green
}

with this Rust:

wasmtime::component::bindgen!({
   path: "test.wit",
});

fn main() {}

gets this error:

error[E0433]: failed to resolve: could not find `green` in the crate root
 --> src/main.rs:1:1
  |
1 | / wasmtime::component::bindgen!({
2 | |    path: "a.wit",
3 | | });
  | |__^ could not find `green` in the crate root
  |

It appears the bindgen-generated bindings for the neptune world use the original name of the interface green rather than the world's name orange.

For comparison, the wit-bindgen guest bindings do appear to use the orange name.