Description:
------------
Currently Closures can not be obtained from trace and thus it is very hard to debug which closure was used/called.

This is a feature request to store the Closures in backtrace instead of strings, or for BC, provide a way how to obtain them from any trace with Closures.

Test script:
---------------
<?php

function dump_closure_details(callable $fx) {
    $r = new \ReflectionFunction($fx);
    var_dump($r->getFileName() . ':' . $r->getStartLine());
}

class Test {
    public function ex() {
        $fx = function() {
            return new \Exception();
        };
        dump_closure_details($fx);
        return $fx();
    }
    
    public function trace() {
        $fx = function() {
            return debug_backtrace();
        };
        dump_closure_details($fx);
        return $fx();
    }
}

$ex = (new Test())->ex();
var_dump($ex->getTrace()[0]['function']); // res['function'] is string...
// dump_closure_details($ex->getTrace()[0]['function']);


$trace = (new Test())->trace();
var_dump($trace[0]['function']); // res['function'] is string...
// dump_closure_details($trace[0]['function']);

// how to get the original closure from the exception trace or backtrace?

Expected result:
----------------
Closure can be obtained from trace and can be called or passed to ReflectionFunction.

Actual result:
--------------
Closure is not presented in trace and there is only "{Closure}" string.