scala - Is it possible to "mix in: additional type constraints -


i'd add constraints type field in trait additional traits mixed in can't seem find way express it. appreciated:

trait events { def be() = println("b") } trait create { self : events => def create() = println("c") } trait update { self : events => def update() = println("u") } trait delete { self : events => def delete() = println("d") }  trait eventhandler {   type myevents <: events   val myevents : myevents }  trait creation {   self: eventhandler =>   override type myevents <: create }  def h(events: eventhandler creation) : unit = {   events.myevents.be()  // <== wont' compile   events.myevents.create() }

compiler says:

<console>:12: error: value not member of events.myevents

ok of previous comments in error, didn't realize self typing hides interface you're working , not same "extends". here's link explains better:

http://www.andrewrollins.com/2014/08/07/scala-cake-pattern-self-type-annotations-vs-inheritance/

there's many logical conflicts creates in code, , won't attempt rework here. conflicts in code come down - of logic opening trait api, , of self-types hiding them. here's example helped me understand why 

trait {    def x:int  }   trait b { self:a =>    }    def workwithb(b:b): unit ={     b.x  //wont' compile, forced hidden.   }

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