diff --git a/jedi/api/__init__.py b/jedi/api/__init__.py
index 1c9f3074..42b1a43d 100644
--- a/jedi/api/__init__.py
+++ b/jedi/api/__init__.py
@@ -509,8 +509,8 @@ class Script(object):
             return []
 
         with common.scale_speed_settings(settings.scale_call_signatures):
-            origins = cache.cache_call_signatures(self._evaluator, stmt, self.source,
-                                                  self._pos, stmt)
+            origins = cache.cache_call_signatures(self._evaluator, stmt,
+                                                  self.source, self._pos)
         debug.speed('func_call followed')
 
         return [classes.CallSignature(self._evaluator, o.name, stmt, call_index, key_name)
diff --git a/jedi/cache.py b/jedi/cache.py
index 023f31e0..68a3cc24 100644
--- a/jedi/cache.py
+++ b/jedi/cache.py
@@ -100,18 +100,18 @@ def time_cache(time_add_setting):
 
 
 @time_cache("call_signatures_validity")
-def cache_call_signatures(evaluator, call, source, user_pos, stmt):
+def cache_call_signatures(evaluator, call, source, user_pos):
     """This function calculates the cache key."""
     index = user_pos[0] - 1
     lines = common.splitlines(source)
 
     before_cursor = lines[index][:user_pos[1]]
-    other_lines = lines[stmt.start_pos[0]:index]
+    other_lines = lines[call.start_pos[0]:index]
     whole = '\n'.join(other_lines + [before_cursor])
     before_bracket = re.match(r'.*\(', whole, re.DOTALL)
 
-    module_path = stmt.get_parent_until().path
-    yield None if module_path is None else (module_path, before_bracket, stmt.start_pos)
+    module_path = call.get_parent_until().path
+    yield None if module_path is None else (module_path, before_bracket, call.start_pos)
     yield evaluator.eval_element(call)