diff --git a/jedi/evaluate/compiled/fake/builtins.pym b/jedi/evaluate/compiled/fake/builtins.pym
index e0046d9c..1283de00 100644
--- a/jedi/evaluate/compiled/fake/builtins.pym
+++ b/jedi/evaluate/compiled/fake/builtins.pym
@@ -156,7 +156,7 @@ class set():
             yield i
 
     def pop(self):
-        return self.__iterable.pop()
+        return list(self.__iterable)[-1]
 
     def copy(self):
         return self
diff --git a/jedi/evaluate/iterable.py b/jedi/evaluate/iterable.py
index 92d24bb4..21cc8e7e 100644
--- a/jedi/evaluate/iterable.py
+++ b/jedi/evaluate/iterable.py
@@ -550,6 +550,11 @@ class ArrayInstance(IterableWrapper):
     Used for the usage of set() and list().
     This is definitely a hack, but a good one :-)
     It makes it possible to use set/list conversions.
+
+    In contrast to Array, ListComprehension and all other iterable types, this
+    is something that is only used inside `evaluate/compiled/fake/builtins.py`
+    and therefore doesn't need `names_dicts`, `py__bool__` and so on, because
+    we don't use these operations in `builtins.py`.
     """
     def __init__(self, evaluator, instance):
         self._evaluator = evaluator