We don't want (fboundp '(lambda ...)) to be true, or (symbol-function '(lambda ...)) to yield a function. This also fixes funny print formatting of lambda expressions. * eval.c (lookup_fun): Do not recognize lambda expressions. Also, return nil for unknown syntax; don't bother looking it up in the hashes. (do_eval): We now have to check for a lambda expression in the car position to evaluate it; lookup_fun will no longer do that. (op_fun): The interpreted fun oprator must also check for lambda itself. (do_expand): A small code change is required here to avoid spuriously warning about a lambda in the car position.