Autoimport doesn't account for overloaded symbols

Example:

mod foo {
    pub mod bar {
        pub fn baz() {}
    }
    pub fn bar() {}
}

use crate::foo::bar;

fn main() {
    bar();
    //         v
    foo::bar::baz();
}

If we put the cursor on baz right under v in the comment and invoke Replace qualified path with use assist.

The following changes will be made:

mod foo {
    pub mod bar {
        pub fn baz() {}
    }
    pub fn bar() {}
}

- use crate::foo::bar;
+ use crate::foo::bar::{self, baz};

fn main() {
    bar();
    foo::bar::baz();
}

which results in invalid code because bar symbol is now imported via self which is only available for module namespace, so bar() call is broken.

Also, when running that assist only the use statement is updated, foo::bar::baz isn't reduced to just baz(), but that looks like an unrelated problem?

Start at the implementation of the “Replace qualified path with use” assist and its existing tests; reproduce the provided overloaded module/function example. Ensure the assist preserves the valid bar() call while importing baz, then add a regression test and separately verify whether path shortening is covered.