diff --git a/jedi/evaluate/finder.py b/jedi/evaluate/finder.py
index bd63bae3..30c1b470 100644
--- a/jedi/evaluate/finder.py
+++ b/jedi/evaluate/finder.py
@@ -301,7 +301,7 @@ def _name_to_types(evaluator, name, scope):
     typ = name.get_definition()
     if typ.isinstance(tree.ForStmt, tree.CompFor):
         container_types = evaluator.eval_element(typ.children[3])
-        for_types = common.unite(iterable.py__iter__(evaluator, container_types))
+        for_types = iterable.py__iter__types(evaluator, container_types)
         types = check_tuple_assignments(for_types, name)
     elif isinstance(typ, tree.Param):
         types = _eval_param(evaluator, typ, scope)
diff --git a/jedi/evaluate/iterable.py b/jedi/evaluate/iterable.py
index d8831bc5..965e1b6c 100644
--- a/jedi/evaluate/iterable.py
+++ b/jedi/evaluate/iterable.py
@@ -500,6 +500,14 @@ def py__iter__(evaluator, types):
                 yield result
 
 
+def py__iter__types(evaluator, types):
+    """
+    Calls `py__iter__`, but ignores the ordering in the end and just returns
+    all types that it contains.
+    """
+    return unite(py__iter__(evaluator, types))
+
+
 def get_iterator_types(evaluator, element):
     """Returns the types of any iterator (arrays, yields, __iter__, etc)."""
     iterators = []
@@ -580,7 +588,8 @@ def _check_array_additions(evaluator, compare_array, module, is_list):
                 result |= unite(evaluator.eval_element(node) for node in nodes)
         elif add_name in ['extend', 'update']:
             for key, nodes in params:
-                result |= unite(get_iterator_types(evaluator, node) for node in nodes)
+                types = unite(evaluator.eval_element(n) for n in nodes)
+                result |= py__iter__types(evaluator, types)
         return result
 
     from jedi.evaluate import representation as er, param
@@ -691,8 +700,8 @@ class _ArrayInstance(IterableWrapper):
         """
         items = set()
         for key, nodes in self.var_args.unpack():
-            for node in nodes:
-                items |= get_iterator_types(self._evaluator, node)
+            types = unite(self._evaluator.eval_element(n) for n in nodes)
+            items |= py__iter__types(self._evaluator, types)
 
         module = self.var_args.get_parent_until()
         is_list = str(self.instance.name) == 'list'
diff --git a/jedi/evaluate/stdlib.py b/jedi/evaluate/stdlib.py
index c5de9ea7..68b42053 100644
--- a/jedi/evaluate/stdlib.py
+++ b/jedi/evaluate/stdlib.py
@@ -153,7 +153,8 @@ def builtins_super(evaluator, types, objects, scope):
 
 def get_iterable_content(evaluator, arguments, argument_index):
     nodes = list(arguments.unpack())[argument_index][1]
-    return unite(iterable.get_iterator_types(evaluator, node) for node in nodes)
+    types = unite(evaluator.eval_element(n) for n in nodes)
+    return iterable.py__iter__types(evaluator, types)
 
 
 @argument_clinic('sequence, /', want_obj=True, want_arguments=True)
diff --git a/jedi/evaluate/sys_path.py b/jedi/evaluate/sys_path.py
index a104bce6..6d177504 100644
--- a/jedi/evaluate/sys_path.py
+++ b/jedi/evaluate/sys_path.py
@@ -118,11 +118,13 @@ def _paths_from_assignment(evaluator, expr_stmt):
         except AssertionError:
             continue
 
-        from jedi.evaluate.iterable import get_iterator_types
+        from jedi.evaluate.iterable import py__iter__
         from jedi.evaluate.precedence import is_string
-        for val in get_iterator_types(evaluator, expr_stmt):
-            if is_string(val):
-                yield val.obj
+        types = evaluator.eval_element(expr_stmt)
+        for types in py__iter__(evaluator, types):
+            for typ in types:
+                if is_string(typ):
+                    yield typ.obj
 
 
 def _paths_from_list_modifications(module_path, trailer1, trailer2):