diff --git a/src/glue.c b/src/glue.c
index 7f9c6fa4b1f2cd0f9ecc28bdfa591aa9bec5914c..2735e4830383d646e5151f94bc36971a4656ad6d 100644
--- a/src/glue.c
+++ b/src/glue.c
@@ -142,7 +142,7 @@ void h_seq_append(HParsedToken *xs, const HParsedToken *ys)
   assert(ys != NULL);
   assert(ys->token_type == TT_SEQUENCE);
 
-  for(size_t i; i<ys->seq->used; i++)
+  for(size_t i=0; i<ys->seq->used; i++)
     h_carray_append(xs->seq, ys->seq->elements[i]);
 }