diff --git a/parser/parser_test.go b/parser/parser_test.go
index 547ebbd6..f9218b75 100644
--- a/parser/parser_test.go
+++ b/parser/parser_test.go
@@ -971,6 +971,14 @@ func TestSyntaxError(t *testing.T) {
 		source string
 		expect string
 	}{
+		{
+			`v: !!int64 2`,
+			`
+[1:4] unknown secondary tag name "!!int64" specified
+>  1 | v: !!int64 2
+          ^
+`,
+		},
 		{
 			`
 a: