It's better, the majority of these changes look more readable to me.
also found some docstrings that had formatting / quoting issues.

Change-Id: I582a45fde3a5648b2f36bab96bad56881321899b

For most from_self() tests, move them into
test/orm/test_deprecated.py and replace the existing
test with one that uses aliased() plus a subquery.
This then revealed a few more issues.

Related items:

* Added slice() method to GenerativeSelect, to match that
  of orm.Query and to make possible migration of one of the
  from_self() tests.  moved the utility functions used for this
  from orm/util into sql/util.

* repairs a caching issue related to subqueryload
  where information being derived from the cached path info
  was mixing up with query information based on the per-query
  state, specifically an AliasedClass that is per query.

* for the above issue, it seemed like path_registry maybe
  had to change so that it represents AliasedClass objects
  as their cache key rather than on identity, but it wasn't
  needed.  still seems like it would be more correct.

* enhances the error message raised by coercions for a case
  such as when an AliasedClass holds onto a select() object
  and not a subquery(); will name the original and resolved
  object for clarity  (although how is AliasedClass able to
  accept a Select() object in the first place?)

* Added _set_propagate_attrs() to Query so that again if
  it's passed to AliasedClass, it doesn't raise an error
  during coercion, but again maybe that should also be
  rejected up front

Fixes: #5368
Change-Id: I5912aa611d899acc87a75eb5ee9f95990592f210

As the test suite has widespread use of many patterns
that are deprecated, enable SQLALCHEMY_WARN_20 globally
for the test suite but then break the warnings filter
out into a whole list of all the individual warnings
we are looking for.  this way individual changesets
can target a specific class of warning, as many of these
warnings will indivdidually affect dozens of files
and potentially hundreds of lines of code.

Many warnings are also resolved here as this
patch started out that way.   From this point
forward there should be changesets that target a
subset of the warnings at a time.

For expediency, updates some migration 2.0 docs
for ORM as well.

Change-Id: I98b8defdf7c37b818b3824d02f7668e3f5f31c94

The ORM Declarative system is now unified into the ORM itself, with new
import spaces under ``sqlalchemy.orm`` and new kinds of mappings.  Support
for decorator-based mappings without using a base class, support for
classical style-mapper() calls that have access to the declarative class
registry for relationships, and full integration of Declarative with 3rd
party class attribute systems like ``dataclasses`` and ``attrs`` is now
supported.

Fixes: #5508
Change-Id: I130b2b6edff6450bfe8a3e6baa099ff04b5471ff

This change includes mainly that the bracketed use within
select() is moved to positional, and keyword arguments are
removed from calls to the select() function.  it does not
yet fully address other issues such as keyword arguments passed
to the table.select().

Additionally, allows False / None to both be considered
as "disable" for all of select.correlate(), select.correlate_except(),
query.correlate(), which establishes consistency with
passing of ``False`` for the legact select(correlate=False)
argument.

Change-Id: Ie6c6e6abfbd3d75d4c8de504c0cf0159e6999108

`AsyncMethodRequired` is actually from
`sqlalchemy.ext.asyncio.exc`, so here it
should be referenced as `async_exc.AsyncMethodRequired`,
instead of `exc.AsyncMethodRequired`.

Fixes: #5529
Closes: #5545
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/5545
Pull-request-sha: d8f885c587dd058f909d4f3bdbec3d0fca176680

Change-Id: I6886558bfd33d3e9e283fbd60c0ec971a1f22c0c

The docs are going to talk a lot about session.execute(select())
for ORM queries, and additionally it's much easier to help
users with queries and such if we can use this new syntax.
I'm hoping to see how hard it is to get a unified tutorial
started that switches to new syntax.  Basically, new syntax
is much easier to explain and less buggy.   But, if we
are starting to present new syntax with the explicit goal
of being easier to explain for less experienced programmers,
the "future" thing is going to just be an impediment
to that.

See if we can remove "future" from session.execute(),
so that ORM-enabled select() statements return ORM results
at that level.  This does not change the presence of the
"future" flag for the Session's construction and for its
transactional behaviors.

The only perceptible change of the future flag for
session.execute() is that session.execute(select()) where the
statement has ORM entities in it now returns ORM new
style tuples rather than old style tuples.   Like
mutating a URL, it's hopefully not very common that people
are doing this.

Change-Id: I0aa10322bb787d554d32772e3bc60548f1bf6206

It's not possible right now to use an association proxy element as a plain
column expression to be SELECTed from or used in a SQL function.  An
informative error is now raised when this occurs.

Fixes: #5542
Change-Id: I334e767ebc0b56c1dccc4a1e5185b0435af77b93

The name of the virtual column used when using the
:class:`_declarative.AbstractConcreteBase` and
:class:`_declarative.ConcreteBase` classes can now be customized, to allow
for models that have a column that is actually named ``type``.  Pull
request courtesy Jesse-Bakker.

Fixes: #5513
Closes: #5514
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/5514
Pull-request-sha: 5e7429f3531e2e22fffe996c9760905578d16ef9

Change-Id: I733737844d4f4e1f52dd2475a66c7044ff7292f5

Using the approach introduced at
https://gist.github.com/zzzeek/6287e28054d3baddc07fa21a7227904e

We can now create asyncio endpoints that are then handled
in "implicit IO" form within the majority of the Core internals.
Then coroutines are re-exposed at the point at which we call
into asyncpg methods.

Patch includes:

* asyncpg dialect

* asyncio package

* engine, result, ORM session classes

* new test fixtures, tests

* some work with pep-484 and a short plugin for the
  pyannotate package, which seems to have so-so results

Change-Id: Idbcc0eff72c4cad572914acdd6f40ddb1aef1a7d
Fixes: #3414