* eval.c (func_get_name): when func_get_name has a nil function argument and nil env, it falls back on method_name, which naively searches its space and finds some static slots with a nil value which is then returned as a method name. Let's put in a type check that the argument must be a function. Also, let's drop the recursion in the nested environment search and switch to iteration, so we don't do these wasteful sanity checks on multiple re-entries of the function.