diff --git a/vlib/v/pref/pref.v b/vlib/v/pref/pref.v
index 1eaf836647..db90b6a6c9 100644
--- a/vlib/v/pref/pref.v
+++ b/vlib/v/pref/pref.v
@@ -338,6 +338,7 @@ pub fn parse_args(known_external_commands []string, args []string) (&Preferences
 			'-g' {
 				res.is_debug = true
 				res.is_vlines = true
+				res.no_parallel = true // TODO: fix `-g` with the parallel backend (line numbers are wrong)
 				res.build_options << arg
 			}
 			'-cg' {