LYR-SEM0202

an assignment written as a condition

warning · spec 08-expressions · lint assignment-in-condition, group correctness, warn unless said

The condition of an if, a while or a do … while is an assignment, where a comparison with == is usually meant.

Explanation

An assignment is an expression whose value is the new value of its target, so if (ready = true) compiles — and is true every time. It is almost always == mistyped.

Write == to compare. To assign on purpose and test the value, write the condition in a second pair of parentheses: if ((ready = next())).

Wrong

fn main(): void {
    var ready = false;
    if (ready = true) {
        ready = false;
    }
    let _ = ready;
}

Right

fn main(): void {
    var ready = false;
    if (ready == true) {
        ready = false;
    }
    let _ = ready;
}