Description:
------------
Module: readline
Function: readline_completion_function
Version: PHP 7.0.0 (cli) (built: Dec  9 2015 16:07:56) ( NTS )

In PHP7 a static array containing possible matches for the readline completion that is returned gets corrupted on the second <TAB>.

If this static array of possible matches contains a string with a length of >= 16, it is changed to "Closure::__invoke".

Other values in the array might simply disappear. (See Test Script Results)

Works fine with PHP5 (5.6.12-0+deb8u1), broken in PHP7.

I'm not an expert in gdb or debugging of C programs, so please forgive me for not adding a gdb backtrace.

Test script:
---------------
<?php
error_reporting(E_ALL);

readline_completion_function(function() {
    static $possible_matches = array(
        'sixteencharacter', // 16 characters or a longer string
        '1',
        '2',
        '3',
        '4',
        '5',
    );

    var_dump($possible_matches);

    return $possible_matches;
});

readline();

Expected result:
----------------
array(6) {
  [0] =>
  string(16) "sixteencharacter"
  [1] =>
  string(1) "1"
  [2] =>
  string(1) "2"
  [3] =>
  string(1) "3"
  [4] =>
  string(1) "4"
  [5] =>
  string(1) "5"
}
array(6) {
  [0] =>
  string(16) "sixteencharacter"
  [1] =>
  string(1) "1"
  [2] =>
  string(1) "2"
  [3] =>
  string(1) "3"
  [4] =>
  string(1) "4"
  [5] =>
  string(1) "5"
}

1                2                3                4                5                sixteencharacter

Actual result:
--------------
array(6) {
  [0]=>
  string(16) "sixteencharacter"
  [1]=>
  string(1) "1"
  [2]=>
  string(1) "2"
  [3]=>
  string(1) "3"
  [4]=>
  string(1) "4"
  [5]=>
  string(1) "5"
}
array(6) {
  [0]=>
  string(17) "Closure::__invoke"
  [1]=>
  string(1) "1"
  [2]=>
  string(1) "2"
  [3]=>
  string(1) "3"
  [4]=>
  string(1) "4"
  [5]=>
  string(0) ""
}

                   1                  2                  3                  4                  Closure::__invoke