Incorrect result in substr

[YuanchengJiang]

Description

The following code:

<?php
namespace foo;
const foo = 1;
const foo = 2;
interface MyInterface {
    const TEST_CONSTANT = true;
}
class ParentClass implements MyInterface { }
class ChildClass extends ParentClass { }
echo (is_subclass_of('ChildClass', 'MyInterface') ? 'true' : 'false') . "\n";
echo (defined('ChildClass::TEST_CONSTANT') ? 'true' : 'false') . "\n";
echo (is_subclass_of('ParentClass', 'MyInterface') ? 'true' : 'false') . "\n";
echo (defined('ParentClass::TEST_CONSTANT') ? 'true' : 'false') . "\n";
$x1=1;
$x2=1;
var_dump('substr');
$callret=substr($x1,$x2,$x1);
print_r($callret);
var_export($callret);
debug_zval_dump($callret);
?>

Resulted in this output (non-JIT):

false
false
false
false
string(6) "substr"
''string(0) "" interned

and (JIT 1211):

false
false
false
false
string(6) "substr"

Fatal error: Uncaught TypeError: substr(): Argument #2 ($offset) must be of type int, string given in /tmp/test.php:17

PHP Version

nightly

Operating System

ubuntu 22.04

[devnexen]

Not sure how much this is an actual bug, cc @iluuu1994

[nielsdos]

This is another duplicate of #15981