cast.hpp helper

I was tired of manually bounds-checking my integer casts.

src/helpers/cast.cpp

@@ -0,0 +1,14 @@
+#include "helpers/cast.hpp"
+#include "global.h"
+
+namespace dusk::helpers::cast::_impl {
+
+void overrun_high() {
+    CRASH("bounded cast overran!");
+}
+
+void overrun_low() {
+    CRASH("bounded cast overran!");
+}
+
+}  // namespace dusk::helpers::cast::_impl