Rustdoc `--passes strip-priv` is broken

[scialex]

According to rustdoc's help text and man page an invocation such as

rustdoc --no-defaults --passes unindent-comments --passes collapse-docs --passes strip-hidden lib.rs

should produce a doc webpage with all modules and functions being documented (except those explicitly marked doc(hidden)).

It does not do this. Instead only the contents of public modules are displayed.

For example the rust code below:

pub use aaa::exp;

/// The abc mod
pub mod abc {
    /// This is public
    pub fn def() {}

    /// This is not
    fn hij() {}
}

/// This should be seen with --no-defaults
mod aaa {
    /// So should this
    fn kkk() {}
    /// And this
    pub fn lll() {}

    /// This is exported
    pub fn exp() {}
}

With the default rustdoc arguments (rustdoc lib.rs) we get this page. We would expect that running the command rustdoc --no-defaults --passes unindent-comments --passes collapse-docs --passes strip-hidden lib.rs would produce a webpage where all items are shown, instead it produces this page. Note the absence of an aaa module in the page. Also note that abc::hij is shown. Finally note that although abc::hij is (correctly) included in the index nothing within the aaa module is.

(Links may take a little bit to start working, they are github pages)

This seems to be because the html renderer is the one that is actually culling private modules from the page.

This is likely related to #19106

[scialex]

Just a note. I tried to fix this before posting this issue, my (not working) CL is at #18822. After spending the better part of a week on it (and making a working fix that was rejected for being hacky) and getting almost nowhere, I do not really have much of an idea of what to do (and also not the time to do it).

[scialex]

Sort of fixed by #18822

Still a huge hack though.