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<?php $a = array(1=>1, "2"=>"2", 3=>"3", "4"=>4); echo json_encode($a,JSON_NUMERIC_CHECK); echo json_encode($a);
Finding entry points
Branch analysis from position: 0
Jump found. Position 1 = -2
filename:       /in/k01cT
function name:  (null)
number of ops:  11
compiled vars:  !0 = $a
line     #* E I O op                           fetch          ext  return  operands
-------------------------------------------------------------------------------------
   2     0  E >   ASSIGN                                                   !0, <array>
   3     1        INIT_FCALL                                               'json_encode'
         2        SEND_VAR                                                 !0
         3        SEND_VAL                                                 32
         4        DO_ICALL                                         $2      
         5        ECHO                                                     $2
   4     6        INIT_FCALL                                               'json_encode'
         7        SEND_VAR                                                 !0
         8        DO_ICALL                                         $3      
         9        ECHO                                                     $3
        10      > RETURN                                                   1

Generated using Vulcan Logic Dumper, using php 7.3.0