Kind of. SBCL will flag type errors at compile time if it can find them, but there isn't any practical way (that I'm aware of) to force it to accept only code t

Kind of. SBCL will flag type errors at compile time if it can find them, but there isn't any practical way (that I'm aware of) to force it to accept only code that has sufficient type annotations that it can be shown to be type correct at compile time. Racket has typed racket, but then you are getting into pretty obscure territory. You might be able to have strict standards for your own code, but you'll still be plugging in to a dynamically typed ecosystem.