title: Are Alias' supposed to cascade when grouping?
body: <p>When grouping by a value which is edited in some way and renamed the same value, the updated value, not the original value, appears to cascade down the select statement.  Is this intended behavior?</p>
  
  <pre><code>SELECT
    a+1 AS a,
    FIRST(a) AS b
  FROM (SELECT 1 AS a),
       (SELECT 2 AS a)
  GROUP BY
    a    
  
  -- a | b
  -- -----
  -- 2 | 2
  -- 3 | 3
  </code></pre>
  
  <p>vs</p>
  
  <pre><code>SELECT
    a+1 AS a_incremented,
    FIRST(a) AS b
  FROM (SELECT 1 AS a),
       (SELECT 2 AS a)
  GROUP BY
    a_incremented
  
  -- a_incremented | b     
  --       2       | 1
  --       3       | 2
  </code></pre>