Type inference regression on beta using `as _`

[bstrie]

Spotted by @gankro :

fn main() {
    let mut x: u64 = 0;
    let y: u32 = 0;
    x += y as _;   // Compiles on stable, fails on beta/nightly
}

[ollie27]

I believe this is expected breakage from #44287.

[jrmuizel]

It would be valuable to have a list breaking changes that's updated whenever something breaking lands.

[emilyalbini]

This also happens when using methods like parse:

fn main() {
    let mut var = 0;
    let other = "10".parse().unwrap();  // Fails on beta/nightly
    var += other;
}

Edit: and also this, which is a bit annoying:

fn main() {
    let mut result = 0;
    result += "10".parse().unwrap();  // Fails on beta/nightly
    println!("{}", result);
}

[Mark-Simulacrum]

Also occurs in average-0.6.2 cc @vks

[Mark-Simulacrum]

As well as:
minions-0.2.8 log cc @dbeck
netlink-rs-0.0.3 cc @crhino
odds-0.2.25 cc @bluss
pbr-demo log cc @samsartor

[Mark-Simulacrum]

And also whiteread-0.4.3 cc @krdln