Welcome to Scala 2.12.0 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_102).
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scala> trait InvariantContainer[Value0] {
     |   type Value = Value0
     | }
defined trait InvariantContainer

scala> type ValueOf[Container <: InvariantContainer[_]] = container.Value forSome { val container: Container }
warning: there was one feature warning; for details, enable `:setting -feature' or `:replay -feature'
defined type alias ValueOf

scala> def intIsValueOfIntContainer(x: Int): ValueOf[InvariantContainer[Int]] = x
intIsValueOfIntContainer: (x: Int)ValueOf[InvariantContainer[Int]]

scala> type OptionValueOf[Container <: InvariantContainer[_]] = Option[ValueOf[Container]]
defined type alias OptionValueOf

scala> def optionIntIsOptionValueOfIntContainer(x: Option[Int]): OptionValueOf[InvariantContainer[Int]] = x
optionIntIsOptionValueOfIntContainer: (x: Option[Int])OptionValueOf[InvariantContainer[Int]]

scala> type InlineOptionValueOf[Container <: InvariantContainer[_]] = Option[container.Value forSome { val container: Container }]
warning: there was one feature warning; for details, enable `:setting -feature' or `:replay -feature'
defined type alias InlineOptionValueOf

scala> def optionIntIsInlineOptionValueOfIntContainer(x: Option[Int]): InlineOptionValueOf[InvariantContainer[Int]] = x
<console>:13: error: type mismatch;
 found   : Option[Int]
 required: InlineOptionValueOf[InvariantContainer[Int]]
    (which expands to)  Option[Int[]]
       def optionIntIsInlineOptionValueOfIntContainer(x: Option[Int]): InlineOptionValueOf[InvariantContainer[Int]] = x
                                                                                                                      ^