Fix double dot range for invalid input

expr_test.go

@@ -812,6 +812,14 @@ func TestExpr(t *testing.T) {
 			`1 + 2 + Three`,
 			6,
 		},
+		{
+			`4 in 5..1`,
+			false,
+		},
+		{
+			`4..0`,
+			[]int{},
+		},
 		{
 			`MapArg({foo: "bar"})`,
 			"bar",

optimizer/const_range.go

@@ -14,6 +14,14 @@ func (*constRange) Exit(node *Node) {
 			if min, ok := n.Left.(*IntegerNode); ok {
 				if max, ok := n.Right.(*IntegerNode); ok {
 					size := max.Value - min.Value + 1
+					// In case the max < min, patch empty slice
+					// as max must be greater than equal to min.
+					if size < 1 {
+						Patch(node, &ConstantNode{
+							Value: make([]int, 0),
+						})
+						return
+					}
 					// In this case array is too big. Skip generation,
 					// and wait for memory budget detection on runtime.
 					if size > 1e6 {

vm/runtime.go

@@ -220,6 +220,9 @@ func exponent(a, b interface{}) float64 {
 
 func makeRange(min, max int) []int {
 	size := max - min + 1
+	if size <= 0 {
+		return []int{}
+	}
 	rng := make([]int, size)
 	for i := range rng {
 		rng[i] = min + i