Sure, that's the case in SBCL - the type inference engine in it is rather advanced; with type declarations here and there (which are capable of turning Common L

Sure, that's the case in SBCL - the type inference engine in it is rather advanced; with type declarations here and there (which are capable of turning Common Lisp into a weakly statically typed language), they are capable of type-optimizing a lot of code. It also generates warnings in case type mismatches are detected at compile-time.