Description:
------------
PHP 7.1.20-1+ubuntu16.04.1+deb.sury.org+1 (cli) (built: Jul 25 2018 10:06:40) ( NTS ) I don't have access to the latest update 7.1.21

The namespace resolution for a function seems to be cached somehow: if you call a function, then eval code to override the function in a namespace then the evaled code won't be run. If you don't call the function before evaling the code, then it's run.



Test script:
---------------
run php test2.php with the line commented
run php test2.php without the line commented

# test.php
<?php

namespace Test;

Class Hello
{

    public function test()
    {
        var_dump('unqualified:' . time());
        if(function_exists('\Test\time')){
           var_dump('fully-qualified:' . \Test\time());
        }
        else{
           var_dump('fully-qualified:not found');
        }
    }

}


# test2.php
<?php

include __DIR__ . '/test.php';

$test = new Test\Hello();

$test->test(); // toggle comment this line

eval('
namespace Test;

function time(){return \'foo\';}
');

$test->test();

Expected result:
----------------
with the line commented:
string(15) "unqualified:foo"
string(19) "fully-qualified:foo"

with the line uncommented:
string(22) "unqualified:1535066193"
string(25) "fully-qualified:not found"
string(22) "unqualified:foo"
string(19) "fully-qualified:foo"

Actual result:
--------------
with the line commented:
string(15) "unqualified:foo"
string(19) "fully-qualified:foo"

with the line uncommented:
string(22) "unqualified:1535066193"
string(25) "fully-qualified:not found"
string(22) "unqualified:1535066193"
string(19) "fully-qualified:foo"