Fix Array.Less slice out of bounds (#362)

Author: marcelocantos

rel/value_set_array.go

@@ -212,7 +212,7 @@ func (a Array) Less(v Value) bool {
 		return a.offset < b.offset
 	}
 	n := len(a.values)
-	if n < len(b.values) {
+	if n > len(b.values) {
 		n = len(b.values)
 	}
 	for i, av := range a.values[:n] {

syntax/expr_set_array_test.go

@@ -42,3 +42,8 @@ func TestArrayWithHoles(t *testing.T) {
 	AssertCodesEvalToSameValue(t, `[10, 11, 12]`, `[10, , 12] with (@: 1, @item: 11)`)
 	AssertCodesEvalToSameValue(t, `[10, 11, 12]`, `[10, , 12, , , ] with (@: 1, @item: 11)`)
 }
+
+func TestSetOfArrays(t *testing.T) {
+	// This tests an error when stringifying sets of arrays.
+	AssertCodesEvalToSameValue(t, `'{[1], [1, 1]}'`, `$'${{[1, 1], [1]}}'`)
+}