rust/src/librustc_error_codes/error_codes/E0364.md

Private items cannot be publicly re-exported. This error indicates that you attempted to pub use a type or value that was not itself public.

Erroneous code example:

mod foo {
    const X: u32 = 1;
}

pub use foo::X;

fn main() {}

The solution to this problem is to ensure that the items that you are re-exporting are themselves marked with pub:

mod foo {
    pub const X: u32 = 1;
}

pub use foo::X;

fn main() {}

See the 'Use Declarations' section of the reference for more information on this topic:

https://doc.rust-lang.org/reference.html#use-declarations