Description:
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I would like to use trigger_error with an error level like this :
DB_FATAL_ERROR = E_USER_ERROR
XML_FATAL_ERROR = E_USER_ERROR + 1
SOMTHING_FATAL_ERROR = E_USER_ERROR + 2
..etc.

In my error_handler, I'll use these error level to change its behaviour.

It could be a great improvement for error managing to define our user error levels.

Reproduce code:
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<?php

trigger_error( 'My error' , E_USER_ERROR + 1 );

?>

Expected result:
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in error_handler, $errno is equal to "E_USER_ERROR + 1"

Actual result:
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"Warning: Invalid error type specified"