1--TEST--
2Print backtrace in fiber
3--FILE--
4<?php
5
6function inner_function(): void
7{
8    debug_print_backtrace();
9}
10
11$fiber = new Fiber(function (): void {
12    inner_function();
13});
14
15$fiber->start();
16
17?>
18--EXPECTF--
19#0 %sdebug-backtrace.php(9): inner_function()
20#1 [internal function]: {closure}()
21#2 %sdebug-backtrace.php(12): Fiber->start()
22