Deceiving PHP Exception Trace

phpDeceivingExceptionPossiblyBug.php

<?php

function traceTest(SplFixedArray $arr, string $str, int $num)
{
	print '----- Before variables changed -----' . PHP_EOL;
	$e = new RuntimeException();
	print $e->getTraceAsString() . PHP_EOL;
	debug_print_backtrace();
	print PHP_EOL;

	// Update variables
	$arr = null;
	$str = 'new';
	$num = 2;

	print '----- After variables changed -----' . PHP_EOL;
	$e = new RuntimeException();
	print $e->getTraceAsString() . PHP_EOL;
	debug_print_backtrace();
}
traceTest(new SplFixedArray(1), 'original', 1);

// Output
/*
----- Before variables changed -----
#0 /path/to/file.php(43): traceTest(Object(SplFixedArray), 'original', 1)
#1 {main}
#0  traceTest(SplFixedArray Object ([0] => ), original, 1) called at [/path/to/file.php:43]

----- After variables changed -----
#0 /path/to/file.php(43): traceTest(NULL, 'new', 2)
#1 {main}
#0  traceTest(, new, 2) called at [/path/to/file.php:43]
*/