Lint for `use ident;`

[jhpratt]

Any statement of the form use ident; is inherently useless, as it brings nothing new into scope. It can safely be removed in all situations (unless there's an edge case I'm not aware of?).

[flip1995]

This is useful to only import crate scopes:

//! lib.rs of crate1
fn foo() {}

//! lib.rs of crate2 
fn foo() {}

So crate1 and crate2 have 2 functions with the same name. Now it is impossible to import both foo functions at the same time directly:

use crate1::foo;
use crate2::foo;

fn main() {
    foo(); // which `foo` is used here?
}

So what you want to do in this situation is

use crate1;
use crate2;

fn main() {
    crate1::foo();
    crate2::foo();
}

---

Something similar is done in clippy, when both hir::Expr and ast::Expr is required in a module.

[jhpratt]

@flip1995 That would only be the case in Rust 2015, correct?

[flip1995]

No this is also the case in rust 2018, like in my example above, which is only valid in the 2018 edition.

[jhpratt]

I think you might not understand exactly what I'm saying. Importing paths is, of course, extremely useful. I agree it's not always feasible to do so. However, in Rust 2018 at least, you could eliminate the use statements from the latter snippet with zero offect whatsoever. This has nothing at all to do with naming conflicts.

[flip1995]

you could eliminate the use statements from the latter snippet with zero offect whatsoever.

Ahhh, now it makes sense. Thanks for clarifying!