Comment 2 for bug 861763

Analysis:
This is an architectural problem in the way ORDER BY expressions
and function arguments are resolved.

Order by expressions are resolved by the procedure find_order_in_list().
This procedure correctly defines the name resolution order to search
first in the SELECT clause and to prefer aliases. The name resolution is
implemented via the call:

  /* Lookup the current GROUP/ORDER field in the SELECT clause. */
  select_item= find_item_in_list(order_item, fields, &counter,
                                 REPORT_EXCEPT_NOT_FOUND, &resolution);

Note however that find_item_in_list() works only for fields (Item_field)
and not functions.

Thus functions in the ORDER clause are not resolved against the
SELECT clause, and find_order_in_list() proceeds until it calls
Item::fix_fields() for these Items.

For functions, fix_fields() calls recursively fix_fields() for its
arguments. Finally we end up calling Item_field::fix_fields() for
the 'LanguageName' argument of e.g. the Collate function.

However Item_field::fix_fields() is designed to resolve fields
mainly in the WHERE and other clauses, where the search order
is different from the one in the ORDER clause. Specifically,
fix_fields() searches first in the FROM clause. As a result, matching
fields in the FROM clause have priority over aliases in the SELECT
clause.

This explains why the first example is resolved correctly, and the
next two - incorrectly.