Missing a single bracket in an import statement can cause tens of cascading errors.

[Frederik-Baetens]

Missing a single bracket, can lead to 8 errors in this case, and 16 in the actual project this sample code comes from.

Example mistake:

use serde::{Deserialize, Serialize//};

Given the following code: https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=015ef4d8827e4c3915e385428acf29fb

use serde::{Deserialize, Serialize//};
use std::net::SocketAddr;

fn main() {
    let addr = "0.0.0.0:8000".parse().unwrap();
    let noderef = NodeRef::new(addr);
    noderef.get("hi");
    noderef.upsert("hi".to_owned(), "hey".to_owned());
    noderef.upsert_prefix_ref("hi", addr);
}

#[derive(Serialize, Deserialize, Copy, Clone, Debug)]
pub struct NodeRef {
    pub address: SocketAddr,
}

impl NodeRef {
    pub fn new(address: SocketAddr) -> NodeRef {
        NodeRef { address }
    }

    pub  fn get(&self, key: &str) -> Option<String> {
        dbg!(key);
        None
    }

    pub  fn upsert(&self, key: String, value: String) {
        dbg!(key, value);
    }

    pub  fn upsert_prefix_ref(&self, prefix: &str, addr: SocketAddr) {
        dbg!(prefix, addr);
    }
}

The current output is:

    Checking errortest v0.1.0 (/home/frederik/Programmeren/rust/errortest)
error: this file contains an unclosed delimiter
  --> src/main.rs:35:2
   |
1  | use serde::{Deserialize, Serialize//};
   |            - unclosed delimiter
...
35 | 
   |  ^

error: expected identifier, found keyword `use`
 --> src/main.rs:2:1
  |
2 | use std::net::SocketAddr;
  | ^^^ expected identifier, found keyword

error: expected one of `,`, `::`, `as`, or `}`, found keyword `use`
 --> src/main.rs:2:1
  |
1 | use serde::{Deserialize, Serialize//};
  |            - unclosed delimiter   - expected one of `,`, `::`, `as`, or `}`
2 | use std::net::SocketAddr;
  | ^^^ unexpected token
  |
help: `}` may belong here
  |
1 | use serde::{Deserialize, Serialize}//};
  |                                   ^
help: missing `,`
  |
1 | use serde::{Deserialize, Serialize,//};
  |                                   ^

error: expected one of `,`, `::`, `as`, or `}`, found `std`
 --> src/main.rs:2:5
  |
2 | use std::net::SocketAddr;
  |    -^^^ expected one of `,`, `::`, `as`, or `}`
  |    |
  |    help: missing `,`

error: expected identifier, found keyword `fn`
 --> src/main.rs:4:1
  |
4 | fn main() {
  | ^^ expected identifier, found keyword

error: expected one of `,`, `::`, `as`, or `}`, found `;`
 --> src/main.rs:2:25
  |
2 | use std::net::SocketAddr;
  |                         ^
  |                         |
  |                         expected one of `,`, `::`, `as`, or `}`
  |                         help: missing `,`

error: expected one of `,`, `::`, `as`, or `}`, found `main`
 --> src/main.rs:4:4
  |
4 | fn main() {
  |   -^^^^ expected one of `,`, `::`, `as`, or `}`
  |   |
  |   help: missing `,`

error: expected one of `,`, `::`, `as`, or `}`, found `(`
 --> src/main.rs:4:8
  |
4 | fn main() {
  |        ^ expected one of `,`, `::`, `as`, or `}`

error: aborting due to 8 previous errors

error: could not compile `errortest`

To learn more, run the command again with --verbose.

Ideally the output should look like:

    Checking errortest v0.1.0 (/home/frederik/Programmeren/rust/errortest)
error: this file contains an unclosed delimiter
  --> src/main.rs:35:2
   |
1  | use serde::{Deserialize, Serialize//};
   |            - unclosed delimiter
...
35 | 
   |  ^

error: aborting due to 1 previous error

error: could not compile `errortest`

To learn more, run the command again with --verbose.

Also the placing of the unclosed delimiter warning arrow seems weird? I think it should point to where I put the // ? Usually rustc error output is pretty good at pointing to where I actually need to make a change.