Generic Type Bug in TypeScript

generic-type-bug.ts

interface Shape {
    name: string;
}

interface Square extends Shape {
    length: number;
}

interface Circle extends Shape {
    radius: number;
}

function test() {
    const circles: Circle[] = [];
    const shapes: Shape[] = circles; // ISSUE: should be syntax error: Type 'Circle[]' is not assignable to type 'Shape[]'
    const square: Square = { name: 'square of length 10', length: 10 };
    const shape: Shape = square;

    shapes.push(shape); // allowed because shapes is a Shape[] in compile time
    shapes.push(square); // same

    const firstCircle: Circle = circles[0]; // this is not a Circle!

    return firstCircle;
}