Fixed regression related to the implementation for the new
"insertmanyvalues" feature where an internal ``TypeError`` would occur in
arrangements where a :func:`_sql.insert` would be referred towards inside
of another :func:`_sql.insert` via a CTE; made additional repairs for this
use case for positional dialects such as asyncpg when using
"insertmanyvalues".

at the core here is a change to positional insertmanyvalues
where we now get exactly the positions for the "manyvalues" within
the larger list, allowing non-"manyvalues" on the left and right
sides at the same time, not assuming anything about how RETURNING
renders etc., since CTEs are in the mix also.

Fixes: #9173
Change-Id: I5ff071fbef0d92a2d6046b9c4e609bb008438afd

Changed how the positional compilation is performed. It's rendered by the compiler
the same as the pyformat compilation. The string is then processed to replace
the placeholders with the correct ones, and to obtain the correct order of the
parameters.
This vastly simplifies the computation of the order of the parameters, that in
case of nested CTE is very hard to compute correctly.

Reworked how numeric paramstyle behavers:
- added support for repeated parameter, without duplicating them like in normal
positional dialects
- implement insertmany support. This requires that the dialect supports out of
order placehoders, since all parameters that are not part of the VALUES clauses
are placed at the beginning of the parameter tuple
- support for different identifiers for a numeric parameter. It's for example
possible to use postgresql style placeholder $1, $2, etc

Added two new dialect based on sqlite to test "numeric" fully using
both :1 style and $1 style. Includes a workaround for SQLite's
not-really-correct numeric implementation.

Changed parmstyle of asyncpg dialect to use numeric, rendering with its native
$ identifiers

Fixes: #8926
Fixes: #8849
Change-Id: I7c640467d49adfe6d795cc84296fc7403dcad4d6

Fixed a series of issues regarding positionally rendered bound parameters,
such as those used for SQLite, asyncpg, MySQL and others. Some compiled
forms would not maintain the order of parameters correctly, such as the
PostgreSQL ``regexp_replace()`` function as well as within the "nesting"
feature of the :class:`.CTE` construct first introduced in :ticket:`4123`.

Fixes: #8827
Change-Id: I9813ed7c358cc5c1e26725c48df546b209a442cb

Fixed issue where referencing a CTE multiple times in conjunction with a
polymorphic SELECT could result in multiple "clones" of the same CTE being
constructed, which would then trigger these two CTEs as duplicates. To
resolve, the two CTEs are deep-compared when this occurs to ensure that
they are equivalent, then are treated as equivalent.

Fixes: #8357
Change-Id: I1f634a9cf7a6c4256912aac1a00506aecea3b0e2

the pep484 task becomes more intense as there is mounting
pressure to come up with a consistency in how data moves
from end-user to instance variable.

current thinking is coming into:

1. there are _typing._XYZArgument objects that represent "what the
   user sent"
2. there's the roles, which represent a kind of "filter" for different
   kinds of objects.   These are mostly important as the argument
   we pass to coerce().
3. there's the thing that coerce() returns, which should be what the
   construct uses as its internal representation of the thing.
   This is _typing._XYZElement.

but there's some controversy over whether or
not we should pass actual ClauseElements around by their role
or not.   I think we shouldn't at the moment, but this makes the
"role-ness" of something a little less portable. Like, we have
to set DMLTableRole for TableClause, Join, and Alias, but then
also we have to repeat those three types in order to set up
_DMLTableElement.

Other change introduced here, there was a deannotate=True
for the left/right of a sql.join().    All tests pass without that.
I'd rather not have that there as if we have a join(A, B) where
A, B are mapped classes, we want them inside of the _annotations.
The rationale seems to be performance, but this performance can
be illustrated to be on the compile side which we hope is cached
in the normal case.

CTEs now accommodate for text selects including recursive.

Get typing to accommodate "util.preloaded" cleanly; add "preloaded"
as a real module.  This seemed like we would have needed
pep562 `__getattr__()` but we don't, just set names in
globals() as we import them.

References: #6810
Change-Id: I34d17f617de2fe2c086fc556bd55748dc782faf0

Fixed regression caused by :ticket:`7760` where the new capabilities of
:class:`.TextualSelect` were not fully implemented within the compiler
properly, leading to issues with composed INSERT constructs such as "INSERT
FROM SELECT" and "INSERT...ON CONFLICT" when combined with CTE and textual
statements.

Fixes: #7798
Change-Id: Ia2ce92507e574dd36fd26dd38ec9dd2713584467

Added new parameter :paramref:`.HasCTE.add_cte.nest_here` to
:meth:`.HasCTE.add_cte` which will "nest" a given :class:`.CTE` at the
level of the parent statement. This parameter is equivalent to using the
:paramref:`.HasCTE.cte.nesting` parameter, but may be more intuitive in
some scenarios as it allows the nesting attribute to be set simultaneously
along with the explicit level of the CTE.

The :meth:`.HasCTE.add_cte` method also accepts multiple CTE objects.

Fixes: #7759
Change-Id: I263c015f5a3f452cb54819aee12bc9bf2953a7bb

Fixed issue where the :meth:`.HasCTE.add_cte` method as called upon a
:class:`.TextualSelect` instance was not being accommodated by the SQL
compiler. The fix additionally adds more "SELECT"-like compiler behavior to
:class:`.TextualSelect` including that DML CTEs such as UPDATE and INSERT
may be accommodated.

Fixes: #7760
Change-Id: Id97062d882e9b2a81b8e31c2bfaa9cfc5f77d5c1

Implemented full support for "truediv" and "floordiv" using the
"/" and "//" operators.  A "truediv" operation between two expressions
using :class:`_types.Integer` now considers the result to be
:class:`_types.Numeric`, and the dialect-level compilation will cast
the right operand to a numeric type on a dialect-specific basis to ensure
truediv is achieved.  For floordiv, conversion is also added for those
databases that don't already do floordiv by default (MySQL, Oracle) and
the ``FLOOR()`` function is rendered in this case, as well as for
cases where the right operand is not an integer (needed for PostgreSQL,
others).

The change resolves issues both with inconsistent behavior of the
division operator on different backends and also fixes an issue where
integer division on Oracle would fail to be able to fetch a result due
to inappropriate outputtypehandlers.

Fixes: #4926
Change-Id: Id54cc018c1fb7a49dd3ce1216d68d40f43fe2659

"Compound select" methods like :meth:`_sql.Select.union`,
:meth:`_sql.Select.intersect_all` etc. now accept ``*other`` as an argument
rather than ``other`` to allow for multiple additional SELECTs to be
compounded with the parent statement at once. In particular, the change as
applied to :meth:`_sql.CTE.union` and :meth:`_sql.CTE.union_all` now allow
for a so-called "non-linear CTE" to be created with the :class:`_sql.CTE`
construct, whereas previously there was no way to have more than two CTE
sub-elements in a UNION together while still correctly calling upon the CTE
in recursive fashion. Pull request courtesy Eric Masseran.

Allow:

```sql
WITH RECURSIVE nodes(x) AS (
   SELECT 59
   UNION
   SELECT aa FROM edge JOIN nodes ON bb=x
   UNION
   SELECT bb FROM edge JOIN nodes ON aa=x
)
SELECT x FROM nodes;
```

Based on @zzzeek suggestion: https://github.com/sqlalchemy/sqlalchemy/pull/7133#issuecomment-933882348

Fixes: #7259
Closes: #7260
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/7260
Pull-request-sha: 2565a5fd4b1940e92125e53aeaa731cc682f49bb

Change-Id: I685c8379762b5fb6ab4107ff8f4d8a4de70c0ca6