Dynamically created trailers need a parent, otherwise it can lead to crashes.

jedi/evaluate/dynamic.py

@@ -53,9 +53,9 @@ def search_params(evaluator, param):
     """
     if not settings.dynamic_params:
         return []
-    debug.dbg('Dynamic param search for %s', param)
 
     func = param.get_parent_until(tree.Function)
+    debug.dbg('Dynamic param search for %s in %s.', param, str(func.name))
     # Compare the param names.
     names = [n for n in search_function_call(evaluator, func)
              if n.value == param.name.value]

jedi/evaluate/representation.py

@@ -506,6 +506,7 @@ class Function(use_metaclass(CachedMetaClass, Wrapper)):
                 if trailer:
                     # Create a trailer and evaluate it.
                     trailer = tree.Node('trailer', trailer)
+                    trailer.parent = dec
                     dec_results = self._evaluator.eval_trailer(dec_results, trailer)
 
                 if not len(dec_results):