The compiler proposes to import non-existing trait

[iamnotacake]

I am using rustc 1.15.1 (021bd294c 2017-02-08), installed with rustup on Arch Linux

Here is code:

// use std::os::ext::fs::MetadataExt;

fn main() {
    let file = std::fs::File::open("/dev/null").unwrap();
    let metadata = file.metadata().unwrap();

    println!("{:?}", metadata.mode());
}

When I try to compile this, I get

error: no method named `mode` found for type `std::fs::Metadata` in the current scope
 --> src/main.rs:9:31
  |
9 |     println!("{:?}", metadata.mode());
  |                               ^^^^
  |
  = help: items from traits can only be used if the trait is in scope; the following trait is implemented but not in scope, perhaps add a `use` for it:
  = help: candidate #1: `use std::os::ext::fs::MetadataExt;`

but when I uncomment first line, I get

error[E0432]: unresolved import `std::os::ext::fs::MetadataExt`
 --> src/main.rs:3:5
  |
3 | use std::os::ext::fs::MetadataExt;
  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Could not find `ext` in `os`

The solution is to use std::os::linux::fs::MetadataExt; and then use st_mode() instead of mode() but that's not good. Compiler must not give me bad advices.

[aidanhs]

This looks the same as #26454

[Aatch]

Duplicate of #26454