E4129

Found cycle in type alias.

错误示例

typealias A = B // Found cycle A -> B -> A in type alias.
typealias B = A

建议

You can break cycle using new type:

type A B
typealias B = A

However, this is equivalent to writing

type A A

And this might not be want to want to do. Therefore, we recommend using newtypes instead of typealiases in most of times:

type A B
type B A