(subrp 'car) => nil
(subrp #'car) => nil
(subrp '+) => nil

(subrp (symbol-function 'car)) => t

According to the doc, subrp should tell me if "OBJECT" is a built-in
function or not. I would expect "car" to be that, since car is implemented
in the C source (in data.c).

I also get the same behavior for compiled-function-p.

Is it not valid to pass a symbol and function objects to those two functions? Can we
 in that case clarify in the doc string expected value(s) for OBJECT?