Description:
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When setting up a custom error handler to deal with errors triggered from within instantiated objects, it would be extremely useful to have a copy of the object the error was triggered from. For instance, when writing a detailed class that will be extended by several individual classes, it would be very useful to have access to things like get_class($errcontext['this']) or individual members, such as an $id member. Having this available within the context passed to the error handler would help narrow down why the error occured.

Currently the only option for this case is to implement a custom error trigger function in the base class, which then calls trigger_error() after prepending the error string with the class name and any useful data. This is an acceptable workaround if there is a particular reason $this is not passed in the error context, but it would be far more convenient in general for these situations, and there are likely other situations I haven't run into yet.

Reproduce code:
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function error_function($errno, $errstr, $errfile, $errline, $errcontext) {
	if(isset($errcontext['this'])) {
		$class = get_class($errcontext['this']);
		$id = $errcontext['this']->id;
		if($id) print "Class $class (ID $id): $errstr";
		print "Class $class (no ID): $errstr";
	}
	print $errstr;
}
set_error_handler('error_function');

class test_class {
	private $id;

	function __construct($id = NULL) {
		$this->id = $id;
		trigger_error('Test error');
	}
}
$test = new test_class(5);

Expected result:
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Class test_class (ID 5): Test error

Actual result:
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Test error