@value interface Type1<#x|> {}

@value interface Type2<#x|> {
  // arg:    contravariant * contravariant * contravariant = contravariant
  // return: contravariant * contravariant = covariant
  something (Type1<Type1<#x>>) -> (Type1<#x>)
}

@type interface Type3<#x|> {
  // arg:    contravariant * contravariant * contravariant = contravariant
  // return: contravariant * contravariant = covariant
  something (Type1<Type1<#x>>) -> (Type1<#x>)
}