diff --git a/src/hb-ot-layout-gsubgpos-private.hh b/src/hb-ot-layout-gsubgpos-private.hh
index 8be431277..2d07a6f2a 100644
--- a/src/hb-ot-layout-gsubgpos-private.hh
+++ b/src/hb-ot-layout-gsubgpos-private.hh
@@ -36,11 +36,11 @@ HB_BEGIN_DECLS
 
 
 /* buffer var allocations */
-#define lig_id() var2.u16[0] /* unique ligature id */
-#define lig_comp() var2.u16[1] /* component number in the ligature (0 = base) */
+#define lig_id() var2.u8[2] /* unique ligature id */
+#define lig_comp() var2.u8[3] /* component number in the ligature (0 = base) */
 
-static inline uint16_t allocate_lig_id (hb_buffer_t *buffer) {
-  uint16_t lig_id = buffer->next_serial ();
+static inline uint8_t allocate_lig_id (hb_buffer_t *buffer) {
+  uint8_t lig_id = buffer->next_serial ();
   if (unlikely (!lig_id)) lig_id = buffer->next_serial (); /* in case of overflow */
   return lig_id;
 }