Incorrect dead-code-warning on enum when using Self

[jfrimmel]

The following code produces an incorrect dead code warning ("warning: variant is never constructed: Variant"), when using the Self keyword. When using the enumeration name (E), there is no warning.

// rustc --edition 2018 --crate-type rlib warning.rs
enum E {
    Variant { _unused: () }
}
impl E {
    fn new() -> Self {
        Self::Variant { _unused: () }
        // E::Variant { _unused: () } // <-- warning vanishes
    }
}
 
pub struct S(E);
impl S {
    pub fn new() -> Self {
        Self(E::new())
    }
}

Tested versions:

rustc 1.41.0 (5e1a79984 2020-01-27)
rustc 1.42.0-nightly (212b2c7da 2020-01-30)
rustc 1.43.0-nightly (58b834344 2020-02-05)

This issue has been assigned to @matprec via this comment.

[matprec]

@rustbot claim

[Lonami]

Possible duplicate of #64362.

[davidvartan]

Seeing this as well (warning occurs with Self::, does not occur when name of enum is used.)

[Lonami]

Looks like #71026 fixed it, I can't reproduce the issue in the current Nightly or even Beta 1.44.