>>1 shadowing

shad.b:12: warning: redeclaration of local n, previously declared as a local on line shad.b:10

request warnings and you'll get them (-w option to limbo)

>>2 no bounds check in JIT

there's a plan to make them available in JIT mode as well.
(at least optionally: there are some things that can be proved
correct and don't need them but could use the speed.)