stawidth inconsistency with all NULL columns

Consider:

CREATE TABLE testwid
(
  txtnotnull text,
  txtnull text,
  int8notnull int8,
  int8null int8
);
INSERT INTO testwid
SELECT 'a' || g.i,
       NULL,
       g.i,
       NULL
FROM generate_series(1,10000) AS g(i);
ANALYZE testwid;
SELECT attname, avg_width FROM pg_stats WHERE tablename = 'testwid';
   attname   | avg_width
-------------+-----------
 txtnotnull  |         5
 txtnull     |         0
 int8notnull |         8
 int8null    |         8
(4 rows)


I see in analyze.c
8<-----------------
/* We can only compute average width if we found some non-null values.*/
if (nonnull_cnt > 0)

  [snip]

else if (null_cnt > 0)
{
    /* We found only nulls; assume the column is entirely null */
    stats->stats_valid = true;
    stats->stanullfrac = 1.0;
    if (is_varwidth)
        stats->stawidth = 0;    /* "unknown" */
    else
        stats->stawidth = stats->attrtype->typlen;
    stats->stadistinct = 0.0;       /* "unknown" */
}
8<-----------------

So apparently intentional, but seems gratuitously inconsistent. Could
this cause any actual inconsistent behaviors? In any case that first
comment does not reflect the code.

Joe
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