diff --git a/spacy/pipeline/transition_parser.pyx b/spacy/pipeline/transition_parser.pyx
index 1a9314eba..15cfc6074 100644
--- a/spacy/pipeline/transition_parser.pyx
+++ b/spacy/pipeline/transition_parser.pyx
@@ -795,8 +795,7 @@ def _states_diff_to_actions(
         c_state_before = before_state.c
         c_state_after = after_state.c
 
-        assert equal(c_state_after.history.begin(),
-            c_state_after.history.begin() + c_state_before.history.size(),
+        assert equal(c_state_before.history.begin(), c_state_before.history.begin(),
             c_state_after.history.begin())
 
     actions = []