diff --git a/src/include/postgres.h b/src/include/postgres.h
index cb9d196..4bf98cf 100644
--- a/src/include/postgres.h
+++ b/src/include/postgres.h
@@ -98,8 +98,8 @@ typedef enum vartag_external
 } vartag_external;
 
 #define VARTAG_SIZE(tag) \
-	((tag) == VARTAG_INDIRECT ? sizeof(varatt_indirect) :		\
-	 (tag) == VARTAG_ONDISK ? sizeof(varatt_external) : \
+	((tag) == VARTAG_INDIRECT ? sizeof(struct varatt_indirect) :		\
+	 (tag) == VARTAG_ONDISK ? sizeof(struct varatt_external) : \
 	 TrapMacro(true, "unknown vartag"))
 
 /*