Request: traits isImplemented

[JS]

I have a request to add to __traits to check if a method/property 
of a class/struct is actually implemented or not.

interface A { void myfunc(); }

class B : A { } // myfunc not implemented
class C : A { void myfunc() { ... } // myfunc implemented

This may seem odd but I need it for conditional mixin compilation 
to add in the methods when they are not implemented. A sort of 
default proxy, wrapper, or composite pattern implementer. It 
reduces boilerplate code significantly.

Unfortunately allMembers returns methods that are not actually 
implemented or part of the class.

Something like allImmediateMembers would be useful where it only 
returns the actually explicit members of the immediate 
class/struct that it is used on and accomplish the same task.