E0021: Field Access on Non-Struct

You tried to access a field on a value that isn't a struct.

Example

fn main() {
    let x = 42;
    let y = x.value;  // Error: cannot access fields on value of type `i64`
}

How to fix

Only access fields on struct values:

struct Point {
    x: i64,
    y: i64,
}

fn main() {
    let p = Point { x: 1, y: 2 };
    let y = p.y;  // OK
}