tree 732ee96d075fbd057e60757674ac8041a5fd30de
parent 543af7425320a88fdef4f5462022e2013f921aaf
author Rosica Dejanovska <rosica@google.com> 1654092331 -0700
committer Copybara-Service <copybara-worker@google.com> 1654092361 -0700

Implement reopened namespaces

For a series of 3 reopened namespaces under the name of outer and inner we generate the following code:

```
pub mod outer_0 {
    pub mod inner_0 {}
}

pub mod outer_1 {
    pub use super::outer_0::*;
    pub mod inner_1 {
        pub use super::inner_0::*;
    }
}

pub mod outer {
    pub use super::outer_1::*;
    pub mod inner {
        pub use super::inner_1::*;
    }
}
```

For this we add two helper maps into our ir:

map <ItemId, usize> => canonical namespace id to number of reopened namespaces

map <ItemId, usize> => reopened namespace id to its ordinal number

PiperOrigin-RevId: 452288159