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Doc Bug #61513 clone operator precedence is wrong
Submitted: 2012-03-26 14:33 UTC Modified: 2020-08-14 08:57 UTC
Votes:2
Avg. Score:2.0 ± 1.0
Reproduced:1 of 1 (100.0%)
Same Version:0 (0.0%)
Same OS:0 (0.0%)
From: antickon at gmail dot com Assigned: cmb (profile)
Status: Closed Package: Documentation problem
PHP Version: 5.3.10 OS:
Private report: No CVE-ID: None
View Developer Edit
 [2012-03-26 14:33 UTC] antickon at gmail dot com 
Description:
------------
---
From manual page: http://www.php.net/language.operators.precedence
---
According to the Operator Precedence table, the clone operator has higher 
precedence than [.

This would mean clone $arraylike[0] is evaluated as ( clone $arraylike )[0], but 
it seems that the implementation does clone ( $arraylike[0] ). I think this is 
probably correct behavior, so I conclude the documentation is incorrect.

Test script:
---------------
$a = array( new stdClass() );
clone $a[0];

Expected result:
----------------
in this case, some type error at runtime since you can't clone an array

Actual result:
--------------
the object at offset 0 is cloned

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 [2012-03-29 13:37 UTC] nikic@php.net 
clone/new are defined with higher precedence in the parser. But there is no general `expr [ dim_offset ]` rule (only specific rules for various variable syntaxes), so it can't be interpreted as `(clone $a)[0]`.

Hard to say what one can do about this in the docs. Maybe removing [ from the list might be a viable option. Variable offset access is kinda outside the normal precedence rules.
 [2012-03-29 13:48 UTC] antickon at gmail dot com 
Even if [ is an amalgam of syntactic constructs, precedence and associativity are 
properties it appears to have. Having it correctly documented is absolutely 
preferable.
 [2018-01-10 10:32 UTC] pasindu@php.net 
So is the suggestions here to remove "[" from the docs or maybe add note about this?
 [2020-08-14 08:57 UTC] cmb@php.net
-Status: Open +Status: Closed -Assigned To: +Assigned To: cmb
 [2020-08-14 08:57 UTC] cmb@php.net 
Fixed with <http://svn.php.net/viewvc?view=revision&revision=347901>.
 
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