Looks like this was fixed it in TS and now no longer errors. So this lesson probably can be omitted: https://github.com/total-typescript/pro-essentials-workshop/blob/main/src/028-mutability/105-includes-on-readonly-arrays.explainer.ts [TSPlayground proof](https://www.typescriptlang.org/play/?ts=3.9.7#code/C4TwDgpgBASg5gIwMIHsA2KBOUC8VMQCGAJigHZohQDaZArgLYISYA0U9TL7nzmAugG4AUAGNyAZ2BRxGTAC5YiVHNw0ATAFZN7AAx6hw4QHpjUAKKZMWCWPRZqu-mt2Copi1ayKAkmWIQAB5QEgCWcGSEwHQEUKFkUKCQUADkBCTklDS83ByMfDz5LPwpUJlUkJgMocAS+ETE8XAAdEZoENI5mBKKMA3lAIJWhCAAPF0AfGrUAIzs6uwAzIZdEs1gdBIAFgAUACwAlG4eltYKUAAK1pWgqRvbpaQQdWQo0kGhUmUJSdBp-RQqF1qCVWiYzAARADy5gAygA5FIAFQsMBgUJgUEIdRQADMoEjwBBYaJMKEwNJFs0AJzNADsdjkzXiAUCUNxOy0mgOjKwzLIojQdACEk52h5QA)
Looks like this was fixed it in TS and now no longer errors.
So this lesson probably can be omitted:
https://github.com/total-typescript/pro-essentials-workshop/blob/main/src/028-mutability/105-includes-on-readonly-arrays.explainer.ts
TSPlayground proof