diff -up libsoup-2.62.2/libsoup/soup-socket.c.coverity-scan-issues libsoup-2.62.2/libsoup/soup-socket.c
--- libsoup-2.62.2/libsoup/soup-socket.c.coverity-scan-issues	2018-05-07 14:02:30.000000000 +0200
+++ libsoup-2.62.2/libsoup/soup-socket.c	2018-06-22 11:25:33.386294057 +0200
@@ -1314,8 +1314,8 @@ soup_socket_listen_full (SoupSocket *soc
 
 		fd = g_socket_get_fd (priv->gsock);
 		v6_only = TRUE;
-		setsockopt (fd, IPPROTO_IPV6, IPV6_V6ONLY,
-			    &v6_only, sizeof (v6_only));
+		g_warn_if_fail (setsockopt (fd, IPPROTO_IPV6, IPV6_V6ONLY,
+			    &v6_only, sizeof (v6_only)) == 0);
 	}
 #endif
 
