[Tistron]

What do you mean with "does not refractor"?

Do you mean it doesn't compile, because it doesn't. You need to write either

    const testVal: MyEnum = "a"

or

    const testVal = "a" as MyEnum

The latter passes typechecking with invalid values, both change automatically for me if I refractor the symbol values in VS Code.

[zdragnar]

It checks fine for me.

    const testVal = "a"

Here, TypeScript infers that it is of type "string", and knows the value, so it is perfectly happy accepting it to ALSO be of type MyEnum. This is the problem- refactoring MyEnum means that testVal is not automatically updated, because the type is really "string" that just-so-happened to duck-type into MyEnum at the function call site.

On the other hand, if MyEnum were actually an enum rather than a union of strings, this problem wouldn't have happened.