diff --git a/generator/GObject.ml b/generator/GObject.ml
index 2c85864f3..0ae283d45 100644
--- a/generator/GObject.ml
+++ b/generator/GObject.ml
@@ -1226,8 +1226,8 @@ guestfs_session_close (GuestfsSession *session, GError **err)
           | n, (FChar|FUInt32|FInt32|FUInt64|FBytes|FInt64|FOptPercent) ->
             pr "%s%s%s = %s%s;\n" indent dst n src n
           | n, FUUID ->
-            pr "%sif (%s%s) memcpy (%s%s, %s%s, sizeof (%s%s));\n"
-              indent src n dst n src n dst n
+            pr "%smemcpy (%s%s, %s%s, sizeof (%s%s));\n"
+              indent dst n src n dst n
           | n, FString ->
             pr "%sif (%s%s) %s%s = g_strdup (%s%s);\n"
               indent src n dst n src n