Description:
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It sometimes happens that you accidentially acces a string via array access and be so unfortunate to have used a string index :-)
Since I see no point in using stingindexes for accessing strings via array access at any time, I propose to issue an E_NOTICE when a string index is cast to integer for array access (on strings), if that is possible.

Test script:
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<?php
$stringValue = 'foobar';

echo $stringValue['baz']; // echoes 'f' since 'baz' is cast to int 0
echo $stringValue['3baz']; // echoes 'b' since the first character of the index string is 3, thus the index string is cast to int 3
echo $stringValue['ba3z']; // echoes 'f' since 'ba3z' is cast to int 0
?>

Expected result:
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f
b
f