> I got really few information on this crash:

Indeed, too few information.  A backtrace[1] could be helpful, an
SSCCE[2] would likely be even more helpful.

[1] <http://bugs.php.net/bugs-generating-backtrace.php>
[2] <http://sscce.org/>

For the backtrace : 

#0  guess_zval_convert (ret=0x7fffffff98d0, type=0x55555636b8e0 <defaultEncoding>, data=0x555556569f50)
    at /home/clement/Downloads/testphp/php-7.3.7/ext/soap/php_encoding.c:2851
#1  0x0000555555889b10 in master_to_zval_int (ret=ret@entry=0x7fffffff98d0, 
    encode=0x55555636b8e0 <defaultEncoding>, data=0x555556569f50)
    at /home/clement/Downloads/testphp/php-7.3.7/ext/soap/php_encoding.c:560
#2  0x0000555555892371 in master_to_zval (ret=ret@entry=0x7fffffff98d0, encode=<optimized out>, 
    data=<optimized out>, data@entry=0x555556569f50)
    at /home/clement/Downloads/testphp/php-7.3.7/ext/soap/php_encoding.c:596
#3  0x00005555558932f8 in model_to_zval_object (ret=ret@entry=0x7fffffff9c70, model=0x7ffff36c9cd8, 
    data=data@entry=0x555556628a10, sdl=sdl@entry=0x7ffff3673100)
    at /home/clement/Downloads/testphp/php-7.3.7/ext/soap/php_encoding.c:1335
#4  0x0000555555893516 in model_to_zval_object (ret=ret@entry=0x7fffffff9c70, model=<optimized out>, 
    data=data@entry=0x555556628a10, sdl=sdl@entry=0x7ffff3673100)
    at /home/clement/Downloads/testphp/php-7.3.7/ext/soap/php_encoding.c:1388
#5  0x0000555555893516 in model_to_zval_object (ret=0x7fffffff9c70, model=<optimized out>, 
    data=0x555556628a10, sdl=0x7ffff3673100)
    at /home/clement/Downloads/testphp/php-7.3.7/ext/soap/php_encoding.c:1388
#6  0x00005555558934aa in model_to_zval_object (ret=ret@entry=0x7fffffff9c70, model=0x7ffff36eb168, 
    data=data@entry=0x555556628a10, sdl=sdl@entry=0x7ffff3673100)
    at /home/clement/Downloads/testphp/php-7.3.7/ext/soap/php_encoding.c:1397
#7  0x0000555555893516 in model_to_zval_object (ret=ret@entry=0x7fffffff9c70, model=<optimized out>, 
    data=data@entry=0x555556628a10, sdl=sdl@entry=0x7ffff3673100)
    at /home/clement/Downloads/testphp/php-7.3.7/ext/soap/php_encoding.c:1388
#8  0x00005555558937f7 in to_zval_object_ex (ret=0x7fffffff9c70, type=<optimized out>, 
    data=0x555556628a10, pce=<optimized out>)
    at /home/clement/Downloads/testphp/php-7.3.7/ext/soap/php_encoding.c:1515
#9  0x0000555555889b10 in master_to_zval_int (ret=ret@entry=0x7fffffff9c70, encode=0x7ffff36e1620, 
    data=0x555556628a10) at /home/clement/Downloads/testphp/php-7.3.7/ext/soap/php_encoding.c:560
#10 0x0000555555892371 in master_to_zval (ret=ret@entry=0x7fffffff9c70, encode=<optimized out>, 
    data=<optimized out>, data@entry=0x555556628a10)
    at /home/clement/Downloads/testphp/php-7.3.7/ext/soap/php_encoding.c:596
#11 0x00005555558932f8 in model_to_zval_object (ret=ret@entry=0x7fffffff9ef0, model=0x7ffff36fc648, 
    data=data@entry=0x5555565691b0, sdl=sdl@entry=0x7ffff3673100)
    at /home/clement/Downloads/testphp/php-7.3.7/ext/soap/php_encoding.c:1335
#12 0x0000555555893516 in model_to_zval_object (ret=ret@entry=0x7fffffff9ef0, model=<optimized out>, 
    data=data@entry=0x5555565691b0, sdl=sdl@entry=0x7ffff3673100)
    at /home/clement/Downloads/testphp/php-7.3.7/ext/soap/php_encoding.c:1388
#13 0x00005555558937f7 in to_zval_object_ex (ret=0x7fffffff9ef0, type=<optimized out>, 
    data=0x5555565691b0, pce=<optimized out>)
    at /home/clement/Downloads/testphp/php-7.3.7/ext/soap/php_encoding.c:1515
#14 0x0000555555889b10 in master_to_zval_int (ret=ret@entry=0x7fffffff9ef0, encode=0x7ffff36f49d8, 
    data=0x5555565691b0) at /home/clement/Downloads/testphp/php-7.3.7/ext/soap/php_encoding.c:560
#15 0x0000555555892371 in master_to_zval (ret=ret@entry=0x7fffffff9ef0, encode=<optimized out>, 
    data=<optimized out>, data@entry=0x5555565691b0)
    at /home/clement/Downloads/testphp/php-7.3.7/ext/soap/php_encoding.c:596
#16 0x000055555589be7e in parse_packet_soap (this_ptr=this_ptr@entry=0x7ffff361d200, 
    buffer=<optimized out>, buffer_size=<optimized out>, fn=0x7ffff366b380, fn_name=<optimized out>, 
    return_value=<optimized out>, soap_headers=0x0)
    at /home/clement/Downloads/testphp/php-7.3.7/ext/soap/php_packet_soap.c:326
#17 0x0000555555888ffd in do_soap_call (this_ptr=this_ptr@entry=0x7ffff361d200, 
    function=0x7ffff366b298 "recupGestionControleTechVehicule", arg_count=1, real_args=0x7ffff36f62f0, 
    return_value=0x7ffff361d180, 
    location=0x7ffff368b088 "https://test-partenaire.utac-otc.com/siv/services/SivOtcServicePort?wsdl", soap_action=0x0, call_uri=0x0, soap_headers=0x0, output_headers=0x0, function_len=<optimized out>, 



And for the sample code, I can share you the php code if you want, but not the wsdl and xsd (private file from our partner who don't want to share them publicly)

Thanks for the backtrace!  Not sure if the code without WSL would
be helpful.

I've pushed a possible fix in https://github.com/php/php-src/commit/a7de2af46ccff1207a7008602b079b92de57a9fe, but as I don't have a way to repro I can't verify that this really fixes your problem, so I'm leaving this issue open for now.

YES IT'S WORKING !!! :) 

Thanks a lot to both of you for this PR and for your time !

Thanks for the quick confirmation!