SQL 2012 XML exist() Function NULL Comparison

The XML data type exist() function comparison of NULL XML instance to zero returns 0 and not 1 as in previous versions. Consider the following code:

DECLARE @test AS XML;

SET @test = NULL;

-- Returns 0 in SQL 2012, and 1 in earlier editions

SELECT COUNT(1) WHERE @test.exist('/whatever') = 0;

-- Returns 1 in all editions

SELECT COUNT(1) WHERE @test.exist('/whatever') IS NULL;

The first query returns 1 in previous editions, while according to other NULL comparisons in SQL Server 0 is expected. This behavior is more consistent than in previous versions.