Exception in thread "main" java.lang.Error: Unresolved compilation problem: The method upcast(Unsound.Constrain<U,B>, B) in the I get compilation why trying this in eclipse on Java 8 but strange when I compile it outside of it, it goes through.

type Unsound.Bind<U> is not applicable for the arguments (Unsound.Constrain<U,capture#1-of ? super T>, T)

at Unsound.coerce(Unsound.java:13) at Unsound.main(Unsound.java:17)