This disables reporting of excess property errors, such as the one shown in the following example:

// @errors: 2322
type Point = { x: number; y: number };
const p: Point = { x: 1, y: 3, m: 10 };

// @errors: 2322
type Point = { x: number; y: number };
const p: Point = { x: 1, y: 3, m: 10 };

This flag was added to help people migrate to the stricter checking of new object literals in TypeScript 1.6.

We don't recommend using this flag in a modern codebase, you can suppress one-off cases where you need it using // @ts-ignore.