Description:
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It seems strange that when the strictest level or error reporting is enabled an E_NOTICE is thrown when attempting to access a non-existent key of an array, but nothing is thrown when attempting to access a non-existent key of a bool, or a string, or it appears any other variable type.  An E_NOTICE will also be thrown if attempting to access a non-existent numerical key in a string, but not if attempting to access a non-existent non-numerical key.

If an E_NOTICE is displayed under one circumstance for an index not existing it seems that it should be displayed under all circumstances when an index doesn't exist.

Reproduce code:
---------------
error_reporting(E_ALL | E_STRICT);

$dummyArray = array();
// this will throw an E_NOTICE
$error = $dummyArray['doesNotExist'];

$dummyArray = true;
// this will not throw an E_NOTICE
$noError = $dummyArray['doesNotExist'];

$dummyArray = 'string';
// this will not throw an E_NOTICE
$noError = $dummyArray['doesNotExist'];
// but this will throw an E_NOTICE
$error = $dummaryArray['100'];


Expected result:
----------------
Notice: Undefined index: doesNotExist
Notice: Undefined index: doesNotExist
Notice: Undefined index: doesNotExist
Notice: Uninitialized string offset:  100

Actual result:
--------------
Notice: Undefined index: doesNotExist
< nothing when attempting to access a non-existent key of a bool >
< nothing when attempting to access a non-existent key of a string >
Notice: Uninitialized string offset:  100