In both languages, the use of a variable is almost always preceded by a binding of that variable to a symbol or var using the "let" form. This accounts for most

In both languages, the use of a variable is almost always preceded by a binding of that variable to a symbol or var using the "let" form. This accounts for most uses of variables, and attempting to access a misspelled variable will flag an error at compile-time. With regard to destructive assignment, most Common Lisp compilers warn on setf calls when executed against unbound symbols. Clojure doesn't have even have assignment in the sense discussed here (refs are bound before use, and the compiler enforces this).