Bug #67750 [Opn]: Subscript Operator claims empty brackets invalid for string

[email protected]
Newsgroups php.standards
Message-ID <[email protected]>
Edit report at https://bugs.php.net/bug.php?id=67750&edit=1

 ID:                 67750
 Updated by:         [email protected]
 Reported by:        ralph-bugsphpnet at inputplus dot co dot uk
 Summary:            Subscript Operator claims empty brackets invalid for
                     string
 Status:             Open
 Type:               Bug
 Package:            PHP Language Specification
 PHP Version:        Irrelevant
 Block user comment: N
 Private report:     N

 New Comment:

"" is a tricky case because in this case $a is converted to array. So strictly speaking [] is not applied to a string, it applies to an array, to which empty string is auto-converted.


Previous Comments:
------------------------------------------------------------------------
[2014-08-02 16:16:45] ralph-bugsphpnet at inputplus dot co dot uk

Description:
------------
https://github.com/php/php-langspec/blob/master/spec/10-expressions.md#subscript-operator says

    *expression* can be omitted only if *subscript-expression* is used in a
    modifiable-lvalue context and *postfix-expression* does not designate a
    string.

Yet this is valid:

    $a =  ""; $a[] = "y"; var_dump($a);

I've omitted expression, postfix-expression is a string, just an empty one.
The result is array("y");  the original empty string disappears.

See http://3v4l.org/vg7Oe for more.

Test script:
---------------
<?php
$a =  ""; $a[] = "y"; var_dump($a);
$b = "x"; $b[] = "y"; var_dump($b);



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Edit this bug report at https://bugs.php.net/bug.php?id=67750&edit=1
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