Knowing the receiver is necessary if you want to differentiate between a NSME on an object that you're invoking a method on and an uncaught NSME originating from somewhere further down in the call stack. Polymer and Angular bindings would like to make such a distinction.

cc @kasperl.

I'd prefer not to try to use the 'receiver' for figuring out where a NSME originates from. It's not a good model for it as it easily breaks down.

I've been toying with the notion of not having noSuchMethod actually do the throwing, but instead have a method on the invocation to do that for us.

   class Object {
     noSuchMethod(invocation) => invocation.notifyAbsent();
   }

   class MyClass {
     noSuchMethod(invocation) {
       if (invocation.memberName....) ...
       return super.noSuchMethod(invocation);
     }
   }

That allows us to pass in an invocation that doesn't throw in case of an absent property (something not handled by the noSuchMethod implementation), which is useful for implementing the reflective "ifAbsent" handling correctly:

   reflect(obj).getField(#foo, ifAbsent: () => 42 + 87)

Small correction. The Invocation.notifyAbsent method should probably take the receiver as an argument like this:

   class Object {
     noSuchMethod(invocation) => invocation.notifyAbsent(this);
   }

Issue #15169 has been merged into this issue.