return ~unused~ from closures passed to GeneratorStart

Author: michaelficarra

spec.html

@@ -46709,10 +46709,10 @@ <h1>Iterator.prototype.drop ( _limit_ )</h1>
               1. If _remaining_ ≠ +∞, then
                 1. Set _remaining_ to _remaining_ - 1.
               1. Let _next_ be ? IteratorStep(_iterated_).
-              1. If _next_ is ~done~, return *undefined*.
+              1. If _next_ is ~done~, return ~unused~.
             1. Repeat,
               1. Let _value_ be ? IteratorStepValue(_iterated_).
-              1. If _value_ is ~done~, return *undefined*.
+              1. If _value_ is ~done~, return ~unused~.
               1. Let _completion_ be Completion(Yield(_value_)).
               1. IfAbruptCloseIterator(_completion_, _iterated_).
           1. Let _result_ be CreateIteratorFromClosure(_closure_, *"Iterator Helper"*, %IteratorHelperPrototype%, « [[UnderlyingIterator]] »).
@@ -46752,7 +46752,7 @@ <h1>Iterator.prototype.filter ( _predicate_ )</h1>
             1. Let _counter_ be 0.
             1. Repeat,
               1. Let _value_ be ? IteratorStepValue(_iterated_).
-              1. If _value_ is ~done~, return *undefined*.
+              1. If _value_ is ~done~, return ~unused~.
               1. Let _selected_ be Completion(Call(_predicate_, *undefined*, « _value_, 𝔽(_counter_) »)).
               1. IfAbruptCloseIterator(_selected_, _iterated_).
               1. If ToBoolean(_selected_) is *true*, then
@@ -46796,7 +46796,7 @@ <h1>Iterator.prototype.flatMap ( _mapper_ )</h1>
             1. Let _counter_ be 0.
             1. Repeat,
               1. Let _value_ be ? IteratorStepValue(_iterated_).
-              1. If _value_ is ~done~, return *undefined*.
+              1. If _value_ is ~done~, return ~unused~.
               1. Let _mapped_ be Completion(Call(_mapper_, *undefined*, « _value_, 𝔽(_counter_) »)).
               1. IfAbruptCloseIterator(_mapped_, _iterated_).
               1. Let _innerIterator_ be Completion(GetIteratorFlattenable(_mapped_, ~reject-primitives~)).
@@ -46850,7 +46850,7 @@ <h1>Iterator.prototype.map ( _mapper_ )</h1>
             1. Let _counter_ be 0.
             1. Repeat,
               1. Let _value_ be ? IteratorStepValue(_iterated_).
-              1. If _value_ is ~done~, return *undefined*.
+              1. If _value_ is ~done~, return ~unused~.
               1. Let _mapped_ be Completion(Call(_mapper_, *undefined*, « _value_, 𝔽(_counter_) »)).
               1. IfAbruptCloseIterator(_mapped_, _iterated_).
               1. Let _completion_ be Completion(Yield(_mapped_)).
@@ -46925,7 +46925,7 @@ <h1>Iterator.prototype.take ( _limit_ )</h1>
               1. If _remaining_ ≠ +∞, then
                 1. Set _remaining_ to _remaining_ - 1.
               1. Let _value_ be ? IteratorStepValue(_iterated_).
-              1. If _value_ is ~done~, return *undefined*.
+              1. If _value_ is ~done~, return ~unused~.
               1. Let _completion_ be Completion(Yield(_value_)).
               1. IfAbruptCloseIterator(_completion_, _iterated_).
           1. Let _result_ be CreateIteratorFromClosure(_closure_, *"Iterator Helper"*, %IteratorHelperPrototype%, « [[UnderlyingIterator]] »).