The main package contains no worlds

[asteurer]

I'm encountering behavior that I don't understand in the latest version of wit-bindgen-go.

I've created a detailed reproduction and summary here

Here's a brief summary:

When I run go tool wit-bindgen-go generate --out internal ./wit I get the following output:

Generated WIT for custom section:
package wasi:clocks@0.2.0;

interface wall-clock {
        /// A time and date in seconds plus nanoseconds.
        record datetime {
                seconds: u64,
                nanoseconds: u32,
        }

        now: func() -> datetime;

        resolution: func() -> datetime;
}

package wasi:filesystem@0.2.0 {
...
}

package wasi:io@0.2.0 {
...
}

error: wasm-tools: error: The main package `wasi:clocks@0.2.0` contains no worlds

Something I noticed in the output: Both the filesystem package and the io package enclose their interfaces with brackets, while the clocks package ends with a semicolon and its corresponding interface is placed below it:

package wasi:clocks@0.2.0;
<INTERFACES>

package wasi:filesystem@0.2.0 {
    <INTERFACES>
}

package wasi:io@0.2.0 {
    <INTERFACES>
}

I tried manually creating the wasi:clocks package in a WIT file and tried inserting the file data in place of the witText variable here; however, it then complains about not having a package header:

error: wasm-tools: error: no `package` header was found in any WIT file for this package

If I try to add a generic package header, we get another "package contains no worlds" error:

error: wasm-tools: error: The main package `foo:bar@0.0.0` contains no worlds