mod_visibility.rs

mod a {
    pub const _A1: i32 = 1;
    const _A2: i32 = 1;

    mod aa {
        pub const _A3: i32 = 1;
        pub const _A4: i32 = 1;
    }

    /// :mod:`aa` is accessible in :mod:`a`
    const _: i32 = aa::_A3;

    /// export `_A4` from :mod:`aa`
    pub use aa::_A4;
}

/// :mod:`a` is accessible
/// even though, member has to be public
fn _a() {
    let _ = a::_A1;
    //let _ = a::_A2; // constant `A2` is private
    //let _ = a::aa::_A3;  // module `aa` is private
    //let _ = a::aa::_A4;  // module `aa` is private
    //let _ = a::_A3;  // constant import `A3` is private

    // exported even :mod:`let _ = aa` is not public
    let _ = a::_A4;
}

mod b {
    pub mod bb {
        pub const _B1: i32 = 1;
        const _B2: i32 = 1;
    }
}

/// nested public module
fn _b() {
    let _ = b::bb::_B1;
    //let _ = b::bb::_B2;  // constant `B2` is private
}

mod c {
    const _C1: i32 = 1;
    pub(self) const _C2: i32 = 1;
}

/// pub(self) == private
fn _c() {
    //let _ = c::_C1;  // constant `C1` is private  private constant
    //let _ = c::_C2;  // constant `C2` is private  private constant
}

/// pub(crate) ~= pub
/// note that external can access pub, but not pub(crate)
mod d {
    mod dd {
        pub const _D1: i32 = 1;
        pub(crate) const _D2: i32 = 1;
        pub(in crate) const _D3: i32 = 1;
    }
    pub mod dp {
        pub const _D4: i32 = 1;
        pub(crate) const _D5: i32 = 1;
        pub(in crate) const _D6: i32 = 1;
    }
    pub mod dn {
        pub mod n {
            pub const _D7: i32 = 1;
            pub(crate) const _D8: i32 = 1;
            pub(in crate) const _D9: i32 = 1;
        }
    }
    /// accessible as well, even if not at the top of crate
    const _: i32 = dn::n::_D7;
    const _: i32 = dn::n::_D8;
    const _: i32 = dn::n::_D9;
}

fn _d() {
    //let _ = d::dd::_D1;  // module `dd` is private 
    //let _ = d::dd::_D2;  // module `dd` is private 
    //let _ = d::dd::_D3;  // module `dd` is private 
    let _ = d::dp::_D4;
    let _ = d::dp::_D5;
    let _ = d::dp::_D6;
}

/// unable to re-export members
/// except for macro
mod e {
    const _E1: i32 = 1;
    //pub use _E1;  // `_E1` is private, and cannot be re-exported
    //pub(crate) use _E1;
    //pub(in crate) use _E1;
    //pub(in super) use _E1;

    macro_rules! e2 { () => {}; }
    //pub use _e2;  //unresolved import `_e2`
    pub(crate) use e2;

    #[macro_export]
    macro_rules! e3 { () => {}; }

    mod e4 {}
    //pub use e4;  // `e4` is private, and cannot be re-exported
    //pub(crate) use e4;
}

fn _e() {
    //e2!();  // cannot find macro `e2` in this scope
    e::e2!();
    e3!();
    //e::e3!();  // failed to resolve: could not find `e3` in `e`
}

/// pub(super) is private for outer scope
/// and able to export
mod f {
    mod n {
        mod nn {
            pub(self) const _F1: i32 = 1;
            pub(super) const _F2: i32 = 1;
            pub(crate) const _F3: i32 = 1;
        }
        //const _: i32 = nn::_F1;  //constant `_F1` is private
        const _: i32 = nn::_F2;
        const _: i32 = nn::_F3;

        pub mod np {
            pub(self) const _F4: i32 = 1;
            pub(super) const _F5: i32 = 1;
            pub(crate) const _F6: i32 = 1;
        }

        /// export `_A5` from :mod:`np`
        pub const _F7: i32 = np::_F5;
    }
    //const _: i32 = n::nn::_F1;  //module `nn` is private
    //const _: i32 = n::nn::_F2;  //module `nn` is private
    //const _: i32 = n::nn::_F3;  //module `nn` is private
    //const _: i32 = n::np::_F4;  //constant `_F4` is private
    //const _: i32 = n::np::_F5;  //constant `_F5` is private
    const _: i32 = n::np::_F6;
    const _: i32 = n::_F7;
}

/// pub(in path)
mod g {
    pub mod h {
        pub mod i {
            /// also:
            /// ```
            /// const _G1: i32 = 1;
            /// pub(self) const _G1: i32 = 1;
            /// pub(in self) const _G1: i32 = 1;
            /// pub(in super::i) const _G1: i32 = 1;
            pub(in crate::g::h::i) const _G1: i32 = 1;

            /// also:
            /// ```
            /// pub(in super) const _G2: i32 = 1;
            pub(in crate::g::h) const _G2: i32 = 1;

            pub(in crate::g) const _G3: i32 = 1;

            /// also:
            /// ```
            /// pub const _G4: i32 = 1;
            /// pub(crate) const _G4: i32 = 1;
            pub(in crate) const _G4: i32 = 1;

            mod j {
                const _: i32 = crate::g::h::i::_G1;
                const _: i32 = super::_G2;
                //const _: i32 = _G3;  //cannot find value `_G3` in this scope
            }
        }
        //const _: i32 = i::_G1;  //constant `_G1` is private
        const _: i32 = i::_G2;

        mod k {
            //const _: i32 = super::i::_G1;  //constant `_G1` is private
            const _: i32 = super::i::_G2;
        }
    }
    //const _: i32 = h::i::_G2;  //constant `_G2` is private
    const _: i32 = h::i::_G3;
}

fn _g() {
    //let _ = g::h::i::_G3;  //constant `_G3` is private
    let _ = g::h::i::_G4;
}

fn main() {}