Discriminated Unions In Switch Statements Don't Respect Destructuring

[axxag]

TypeScript Version: 2.3.2

Code

interface Square {
    kind: "square";
    size: number;
}
interface Circle {
    kind: "circle";
    radius: number;
}

type Shape = Square | Circle

const area = (s: Shape) => { //Works
    switch (s.kind) {
        case "square": return s.size * s.size;
        case "circle": return Math.PI * s.radius ** 2;
    }
}

const area = (s: Shape) => {
    const {kind} = s
    switch (kind) {
        case "square": return s.size * s.size; // size doesn't exist on Circle
        case "circle": return Math.PI * s.radius ** 2;  // radius doesn't exist on Square
    }
}

[mhegazy]

Duplicate of #10976

[mhegazy]

Automatically closing this issue for housekeeping purposes. The issue labels indicate that it is unactionable at the moment or has already been addressed.