Common errors

Most mistakes are compile errors. Each has a code; the message points at the line and often suggests the fix. A runtime failure is a panic: thread 'main' panicked at main.rs:7:21: followed by the reason, and the program exits with status 101.

• error[E0382]: borrow of moved value — the value was moved to another variable or function. Borrow with & instead, or .clone() it.
• error[E0502]: cannot borrow 'v' as mutable because it is also borrowed as immutable — finish using the & borrow before changing the value (e.g. do not push while looping over &v).
• error[E0384]: cannot assign twice to immutable variable — declare it with let mut.
• error[E0308]: mismatched types — convert with as, .to_string(), parse(); or remove a ; after the value a function should return.
• error[E0425]: cannot find value 'x' in this scope — a typo, or the variable belongs to another block.
• index out of bounds: the len is 3 but the index is 5 — use v.get(i) when the index may be too large.
• called Option::unwrap() on a None value / called Result::unwrap() on an Err value — handle the missing or failed case with match, if let or unwrap_or.

fn main() {
    let mut total = 0;
    for v in ["10", "x", "7"] {
        match v.parse::<i32>() {
            Ok(n) => total += n,
            Err(_) => println!("skipped {v:?}"),
        }
    }
    println!("total: {total}");
}

skipped "x"
total: 17