"Replace qualified path with use" should replace all paths in the module

[jonas-schievink]

When running assists like "Implement missing members" or "Fill match arms", rust-analyzer will qualify all paths in the inserted code as necessary for them to resolve correctly. However, this can create rather long paths, which require many uses of the "Replace qualified path with use" assist to make the code more readable.

This could be fixed by having the "Replace qualified path with use" assist not just replace the path it is invoked on, but all paths in the module that refer to the imported item.

For example:

fn f(e: m::n::Enum) {
    match e {
        m::n::E<|>num::A => {}
        m::n::Enum::B => {}
        m::n::Enum::C => {}
        m::n::Enum::D => {}
    }
}

Invoking "Replace qualified path with use" once at this point should result in the code below:

fn f(e: Enum) {
    match e {
        Enum::A => {}
        Enum::B => {}
        Enum::C => {}
        Enum::D => {}
    }
}

[SuperFluffy]

Commenting here because it seems relevant (should I open a new issue?).

replace_qualified_path_with_use does not work for paths to the same type constructor but with different type parameter. In the example below std::pin::Pin<T> only gets replaced for those instances where T is the same. However, for U != T nothing changes.

Before running replace_qualified_path_with_use:

use futures::FutureExt;
use std::{
    future::Future,
    task::{
        Context,
        Poll,
    },
    time::Duration,
};
use tokio::time::Sleep;

struct MyFuture {
    sleep: std::pin::Pin<Box<Sleep>>,
}

impl Future for MyFuture {
    type Output = ();

    fn poll(mut self: std::pin::Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
        println!("MyFuture::poll()");
        self.sleep.poll_unpin(cx)
    }
}

After having run replace_qualified_path_with_use on either occurence of Pin (second one for demonstration purposes; similar result for the first one):

use futures::FutureExt;
use std::{future::Future, pin::Pin, task::{
        Context,
        Poll,
    }, time::Duration};
use tokio::time::Sleep;

struct MyFuture {
    sleep: std::pin::Pin<Box<Sleep>>,
}

impl Future for MyFuture {
    type Output = ();

    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
        println!("MyFuture::poll()");
        self.sleep.poll_unpin(cx)
    }
}

You can see that std::pin::Pin<Box<Sleep>> was not changed. Not shown here: a second instance of std::pin::Pin<&mut Self> would have been correctly truncated to Pin<&mut Self>.

[flodiebold]

@SuperFluffy since this is closed, I think it'd be better to open a new issue 🙂