# Breaking changes in v18

Adds `@typescript-eslint/consistent-type-assertions` configuration, which will raise errors in consumer repos. We have multiple years of relying on `as` casting as a TypeScript work-around (which is dangerous, compared to type-narrowing in runtime code) in our code, so this specific rule change will require a large amount of effort for compliance--even if adding `// eslint-disable` to all existing instances, or adding [eslint-seatbelt](https://www.notion.com/blog/how-we-evolved-our-code-notions-ratcheting-system-using-custom-eslint-rules)--and so we are marking it as a new major version.