@value interface Type1 {}

@value interface Type2 {
  refines Type1
}

@value interface Type3 {
  refines Type2
}

@value interface Interface1<|#x> {
  something (Type2) -> (Type1)
}

@value interface Interface2 {
  something (Type3) -> (Type2)
}

@value interface Test1 {
  refines Interface1<Type2>
  refines Interface2

  something (Type2) -> (Type2)
}

@value interface Test2 {
  refines Interface1<Type3>
  refines Test1

  // something must be merged again, since Interface1 is inherited again.
}