3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php var_dump(substr((string)null, 0, 4));
based on 2EIQC
Finding entry points
Branch analysis from position: 0
Jump found. Position 1 = -2
filename:       /in/O3nY3
function name:  (null)
number of ops:  10
compiled vars:  none
line     #* E I O op                           fetch          ext  return  operands
-------------------------------------------------------------------------------------
   2     0  E >   INIT_FCALL                                               'var_dump'
         1        INIT_FCALL                                               'substr'
         2        CAST                                          6  ~0      null
         3        SEND_VAL                                                 ~0
         4        SEND_VAL                                                 0
         5        SEND_VAL                                                 4
         6        DO_ICALL                                         $1      
         7        SEND_VAR                                                 $1
         8        DO_ICALL                                                 
         9      > RETURN                                                   1

Generated using Vulcan Logic Dumper, using php 7.3.0