prevent unhashable panic

src/built-ins.go

@@ -42,6 +42,10 @@ func init() {
 				switch y := v.(type) {
 				case ArArray:
 					if len(y) == 2 {
+						keytype := typeof(y[0])
+						if keytype == "array" || keytype == "map" {
+							return nil, ArErr{TYPE: "TypeError", message: "Cannot use unhashable value as key: " + keytype, EXISTS: true}
+						}
 						newmap[y[0]] = y[1]
 						continue
 					}