**TypeScript Version:** 2.2.0 **Code** ```ts class Foo { bar: "boop"; } class Buzz extends Foo { bar = 'boop' } ``` [Playground Link](https://www.typescriptlang.org/play/index.html#src=class%20Foo%20%7B%0D%0A%20%20%20%20bar%3A%20%22boop%22%3B%0D%0A%7D%0D%0A%0D%0Aclass%20Buzz%20extends%20Foo%20%7B%0D%0A%20%20%20%20bar%20%3D%20'boop'%0D%0A%7D%0D%0A) **Expected behavior:** Compiles without error. **Actual behavior:** ``` Class 'Buzz' incorrectly extends base class 'Foo'. Types of property 'bar' are incompatible. Type 'string' is not assignable to type '"boop"'. ``` ---- Apologies if I'm missing something obvious, this is by design, or there are existing issues for this. I searched and didn't find anything like it.