Associated functions on extern types not found across crates

[SimonSapin]

Crate a:

#![feature(extern_types)]

extern {
    pub type Void;
}

impl Void {
    /// Similar to `std::ptr::null_mut`, which requires `T: Sized`.
    pub fn null_mut() -> *mut Self {
        0 as _
    }
}

pub fn foo() {
    let _ = Void::null_mut();  // This is fine
}

Crate b:

extern crate a;

fn main() {
    let _ = a::Void::null_mut();
}

error[E0599]: no function or associated item named `null_mut` found for type `a::Void` in the current scope
 --> src/main.rs:4:13
  |
4 |     let _ = a::Void::null_mut();
  |             ^^^^^^^^^^^^^^^^^ function or associated item not found in `a::Void`

[crumblingstatue]

Probably the same issue as #46665

[SimonSapin]

Yes it is, thanks.