diff --git a/vlib/compiler/parser.v b/vlib/compiler/parser.v
index 07ae9a83cb..0ff8619181 100644
--- a/vlib/compiler/parser.v
+++ b/vlib/compiler/parser.v
@@ -2623,6 +2623,7 @@ fn (p mut Parser) assoc() string {
 		p.error('unknown variable `$name`')
 		exit(1)
 	}
+	p.mark_var_used(var)
 	p.check(.pipe)
 	p.gen('($var.typ){')
 	mut fields := []string// track the fields user is setting, the rest will be copied from the old object