diff --git a/jedi/evaluate/helpers.py b/jedi/evaluate/helpers.py
index b80f42d0..a013ab5c 100644
--- a/jedi/evaluate/helpers.py
+++ b/jedi/evaluate/helpers.py
@@ -5,7 +5,7 @@ from jedi.parser import representation as pr
 from jedi import debug
 
 
-def fast_parent_copy(obj, new_elements_default=None):
+def deep_ast_copy(obj, new_elements_default=None):
     """
     Much, much faster than copy.deepcopy, but just for Parser elements (Doesn't
     copy parents).
@@ -132,7 +132,7 @@ def search_call_signatures(user_stmt, position):
     call, arr, index = None, None, 0
     if user_stmt is not None and isinstance(user_stmt, pr.Statement):
         # some parts will of the statement will be removed
-        user_stmt = fast_parent_copy(user_stmt)
+        user_stmt = deep_ast_copy(user_stmt)
         arr, index, call = call_signature_array_for_pos(user_stmt, position)
 
         # Now remove the part after the call. Including the array from the
diff --git a/jedi/evaluate/representation.py b/jedi/evaluate/representation.py
index 02cd0e91..5b128788 100644
--- a/jedi/evaluate/representation.py
+++ b/jedi/evaluate/representation.py
@@ -509,7 +509,7 @@ class FunctionExecution(Executed):
     """
     def __init__(self, evaluator, base, *args, **kwargs):
         super(FunctionExecution, self).__init__(evaluator, base, *args, **kwargs)
-        # for fast_parent_copy
+        # for deep_ast_copy
         self._copy_dict = {base.base_func: self}
 
     @memoize_default(default=())
@@ -579,7 +579,7 @@ class FunctionExecution(Executed):
         objects = []
         for element in lst:
             self._scope_copy(element.parent)
-            copied = helpers.fast_parent_copy(element, self._copy_dict)
+            copied = helpers.deep_ast_copy(element, self._copy_dict)
             objects.append(copied)
         return objects
 
@@ -593,7 +593,7 @@ class FunctionExecution(Executed):
         if scope != self.base.base_func:
             # Just make sure the parents been copied.
             self._scope_copy(scope.parent)
-            helpers.fast_parent_copy(scope, self._copy_dict)
+            helpers.deep_ast_copy(scope, self._copy_dict)
 
     @common.safe_property
     @memoize_default([])
diff --git a/test/test_evaluate/test_helpers.py b/test/test_evaluate/test_helpers.py
index 763a89b4..38c91267 100644
--- a/test/test_evaluate/test_helpers.py
+++ b/test/test_evaluate/test_helpers.py
@@ -1,10 +1,10 @@
-from jedi.evaluate.helpers import fast_parent_copy
+from jedi.evaluate.helpers import deep_ast_copy
 from jedi.parser import representation as pr
 
 
-def test_fast_parent_copy():
+def test_deep_ast_copy():
     name = pr.Name(object, [('hallo', (0, 0))], (0, 0), (0, 0))
 
     # fast parent copy should switch parent
-    new_name = fast_parent_copy(name)
+    new_name = deep_ast_copy(name)
     assert new_name.names[0].parent == new_name