One of them is quite serious: the function table_cond_selectivity used
the TABLE_REF structure for ref/eq_ref access methods as if they had been
filled. In  fact these structure are filled after the best execution plan
has been chosen.

The other bugs happened due to:
- an erroneous attempt at get statistics on the result of materialization
  of a view
- incorrect handling of ranges with no left/right limits when calculating
  selectivity of range conditions on non-indexed columns
- lack of cleanup for some newly introduced fields