PHP Fatal error: Class Foo cannot implement previously implemented interface Stringable in Unknown on line 0

[clearair]

Hi
I encountered an issue with the __toString method

rust 1.80
ext-php-rs 0.12.0
php 8.3

rust code

use ext_php_rs::{info_table_end, info_table_row, info_table_start, prelude::*};
use ext_php_rs::{exception::PhpResult, types::Zval, zend::ce};
use ext_php_rs::zend::ModuleEntry;

#[php_class(name = "Foo")]
#[implements(ce::stringable())]
#[implements(ce::countable())]
#[derive(Default)]
pub struct Foo {
}

#[php_impl]
impl Foo {
    #[constructor]
    pub fn __construct() -> Self {
        Foo {
           
        }
    }

    pub fn __to_string(&self) -> String {
        format!("string")
    }

    pub fn count(&self) -> i32 {
       1
    }
}

/// Used by the `phpinfo()` function and when you run `php -i`.
pub extern "C" fn php_module_info(_module: *mut ModuleEntry) {
    info_table_start!();
    info_table_row!("Foo", "enabled");
    info_table_end!();
}

#[php_module]
pub fn module(module: ModuleBuilder) -> ModuleBuilder {
    module
}

php code

<?php

$foo = new Foo();

echo $foo;

php -d extension=./target/debug/libphp_foo.so test.php
PHP Fatal error: Class Foo cannot implement previously implemented interface Stringable in Unknown on line 0
[1] 266183 IOT instruction php -d extension=./target/debug/libphp_foo.so test.php