VS code doesn't give the type for the 'count' variable

[jrmuizel]

In the following code RLS can't seem to figure out the type of 'count'. It figures out line just fine.

use std::fs::File;
use std::io::BufReader;
use std::io::BufRead;

use std::collections::BTreeMap;
use std::collections::btree_map::Entry::*;
use std::env;

fn main() {
    let arg = env::args().nth(1).unwrap();
    let f = File::open(arg).unwrap();
    let mut uniq = BTreeMap::new();
    for l in BufReader::new(&f).lines() {
        let l = l.unwrap();
        match uniq.entry(l) {
            Vacant(v) => { v.insert(1); }
            Occupied(mut o) => { let r = o.get_mut(); *r = *r + 1; }
        }
    }

    for (line, count) in uniq.iter() {
        println!("{} {}", line, count);
    }

}

[sophiajt]

If you hover count in the body, it does work, but not in the destructure.

Also noticed that .lines() doesn't get a hover.

[jrmuizel]

It gives me a type of 'fn () -> ()' for count in the body which is wrong. It should be &i32.

[sophiajt]

Playing with this example, it seems that count is missing or wrong, but if you comment out any of the lines before it, the type is correctly guessed:

use std::fs::File;
use std::io::BufReader;
use std::io::BufRead;

use std::collections::BTreeMap;
use std::collections::btree_map::Entry::*;
use std::env;

fn main() {
    let arg = env::args().nth(1).unwrap();
    let f = File::open(arg).unwrap();
    let mut uniq: BTreeMap<String, u32> = BTreeMap::new();
    for l in BufReader::new(&f).lines() {
        let l = l.unwrap();
        match uniq.entry(l) {
            Vacant(v) => { /*v.insert(1);*/ }
            Occupied(mut o) => { let r = o.get_mut(); *r = *r + 1; }
        }
    }

    let (line, count) = uniq.iter().next().unwrap();
}

If you change Vacant(v) to Vacant(_) it seems to correctly guess the type.

[nrc]

cc rust-dev-tools/rls-analysis#78