diff --git a/spacy/syntax/_beam_utils.pxd b/spacy/syntax/_beam_utils.pxd
index 7bae17558..36b0c05da 100644
--- a/spacy/syntax/_beam_utils.pxd
+++ b/spacy/syntax/_beam_utils.pxd
@@ -1,6 +1,9 @@
-from thinc.typedefs cimport class_t
+from thinc.typedefs cimport class_t, hash_t
 
 # These are passed as callbacks to thinc.search.Beam
 cdef int transition_state(void* _dest, void* _src, class_t clas, void* _moves) except -1
 
 cdef int check_final_state(void* _state, void* extra_args) except -1
+
+
+cdef hash_t hash_state(void* _state, void* _) except 0