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From: Meredith Montgomery <mmontgomery@levado.to>
Newsgroups: comp.lang.php
Subject: php 7.4: null["key"]
Date: Fri, 20 May 2022 17:34:12 -0300
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I'm upgrading code to PHP 7.4, which will now blow a notice for things
such as

  null["key"]
  (1.2)["key"]
  (123)["key"]

All of these seem to reduce to null.  (The footnote explains why I think
so.)

I have a lot of code which could be depending on such things.  I'd like
to rewrite such code, but I have no idea how to find such code.  I
suppose a loop such as

  while ($a["key"]) { ... }

could be depending on $a sometimes being null or even being undefined
(because ``$a === null'' when $a is undefined).  (These are very weird
things about PHP to my way of looking at things.)

How would you search for something like that?  I just have no idea.  My
best idea is to just watch a log of errors and notices and try to spot
the code that way.

(*) Footnote

I say this because of 

--8<---------------cut here---------------start------------->8---
php > var_dump((123)["key"] === null);
PHP Notice: Trying to access array offset on value of type int in php
shell code on line 1

Notice: Trying to access array offset on value of type int in php shell
code on line 1
bool(true)
php >
--8<---------------cut here---------------end--------------->8---

(By the way, I don't know why I get two notices.)