diff --git a/jedi/evaluate/syntax_tree.py b/jedi/evaluate/syntax_tree.py
index 984434fc..aa0a225c 100644
--- a/jedi/evaluate/syntax_tree.py
+++ b/jedi/evaluate/syntax_tree.py
@@ -100,7 +100,7 @@ def eval_node(context, element):
         # Must be an ellipsis, other operators are not evaluated.
         # In Python 2 ellipsis is coded as three single dot tokens, not
         # as one token 3 dot token.
-        assert element.value in ('.', '...')
+        assert element.value in ('.', '...'), 'value is actually ' + element.value
         return ContextSet(compiled.create(evaluator, Ellipsis))
     elif typ == 'dotted_name':
         context_set = eval_atom(context, element.children[0])
@@ -148,7 +148,7 @@ def eval_trailer(context, base_contexts, trailer):
                 name_or_str=node
             )
         else:
-            assert trailer_op == '('
+            assert trailer_op == '(', 'trailer_op is actually %s' % trailer_op
             args = arguments.TreeArguments(context.evaluator, context, node, trailer)
             return base_contexts.execute(args)