diff --git a/src/hb-set-private.hh b/src/hb-set-private.hh
index be0a90d7f..689766c13 100644
--- a/src/hb-set-private.hh
+++ b/src/hb-set-private.hh
@@ -148,7 +148,7 @@ struct hb_set_t
 
     static const unsigned int ELT_BITS = sizeof (elt_t) * 8;
     static const unsigned int ELT_MASK = ELT_BITS - 1;
-    static const unsigned int BITS = sizeof (v) * 8;
+    static const unsigned int BITS = sizeof (vector_t) * 8;
     static const unsigned int MASK = BITS - 1;
     static_assert (PAGE_BITS == BITS, "");