scala - Type aliasing type constraints in generics -

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i have situation want use bounded generic type constraint on class can produced. problem need 

abstract class someabstractclass  trait foo[a <: someabstractclass]  trait bar[a] extends foo[a]     //  fails error: type arguments [a] not conform trait foo's type parameter bounds [a <: someabstractclass]  // need write this, every single subclass of foo trait bar[a <: someabstractclass] extends foo[a]

is there easier way promote through system without having retype bounds every time?

constraints on type parameters constraints. don't propagate transitively via inheritance them to.


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