Why doesn't try catch work on a variable that is executed as a function?

Question

PHP

There is a block of code:
There is a function in $process that is not available (I mean it should not be called)
I'm trying to catch this function, but I don't understand why I can't catch it. The exception still crashes and the ketch does not work.

foreach ($element['#process'] as $process) {
        try 
        {
                $element = $process($element, $form_state, $form_state['complete form']);
        }
        catch(Exception $e)
       {
            xdebug_var_dump($element);
       }

EDIT:
Error message:

Error: Call to undefined function bootstrap_form_process() in form_builder() (line 1873 of /usr/share/nginx/html/

Answer 1

What's the error?
If syntactic, then it will continue to fall, it falls at the start, and not during execution.