diff --git a/vlib/builtin/array_test.v b/vlib/builtin/array_test.v
index 11104cbbaa..9863f5cef0 100644
--- a/vlib/builtin/array_test.v
+++ b/vlib/builtin/array_test.v
@@ -117,8 +117,11 @@ fn test_repeat() {
 fn test_right() {
 	a := [1, 2, 3, 4]
 	b := a.right(1)
+	c := a[1..a.len]
 	assert b[0] == 2
 	assert b[1] == 3
+	assert c[0] == 2
+	assert c[1] == 3
 }
 
 fn test_right_with_n_bigger_than_array_size() {
@@ -138,8 +141,11 @@ fn test_right_with_n_bigger_than_array_size() {
 fn test_left() {
 	a := [1, 2, 3]
 	b := a.left(2)
+	c := a[0..2]
 	assert b[0] == 1
 	assert b[1] == 2
+	assert c[0] == 1
+	assert c[1] == 2
 }
 
 fn test_slice() {
diff --git a/vlib/builtin/string_test.v b/vlib/builtin/string_test.v
index 7619027940..e4c9b362d2 100644
--- a/vlib/builtin/string_test.v
+++ b/vlib/builtin/string_test.v
@@ -208,6 +208,8 @@ fn test_runes() {
 	assert u.len == 6
 	assert s2.substr(1, 4).len == 3
 	assert s2.substr(1, 4) == 'riv'
+	assert s2[1..4].len == 3
+	assert s2[1..4] == 'riv'
 	assert u.substr(1, 4).len == 6
 	assert u.substr(1, 4) == 'рив'
 	assert s2.substr(1, 2) == 'r'