Change-Id: I488c9557eda390e4a88319affd4c8813ee274f80

Fixed two distinct issues, each of which would come into play under certain
circumstances, most likely however one which is a common mis-configuration
in :class:`_hybrid.hybrid_property`, where the "expression" implementation
would return a non :class:`_sql.ClauseElement` such as a boolean value.
For both issues, 1.3's behavior was to silently ignore the
mis-configuration and ultimately attempt to interpret the value as a
SQL expression, which would lead to an incorrect query.

* Fixed issue regarding interaction of the attribute system with
hybrid_property, where if the ``__clause_element__()`` method of the
attribute returned a non-:class:`_sql.ClauseElement` object, an internal
``AttributeError`` would lead the attribute to return the ``expression``
function on the hybrid_property itself, as the attribute error was
against the name ``.expression`` which would invoke the ``__getattr__()``
method as a fallback. This now raises explicitly. In 1.3 the
non-:class:`_sql.ClauseElement` was returned directly.

* Fixed issue in SQL argument coercions system where passing the wrong
kind of object to methods that expect column expressions would fail if
the object were altogether not a SQLAlchemy object, such as a Python
function, in cases where the object were not just coerced into a bound
value. Again 1.3 did not have a comprehensive argument coercion system
so this case would also pass silently.

Fixes: #6350
Change-Id: I5bba0a6b27f45e5f8ebadfd6d511fa773388ef7c

Executing a :class:`_sql.Subquery` using :meth:`_engine.Connection.execute`
is deprecated and will emit a deprecation warning; this use case was an
oversight that should have been removed from 1.4. The operation will now
execute the underlying :class:`_sql.Select` object directly for backwards
compatibility. Similarly, the :class:`_sql.CTE` class is also not
appropriate for execution. In 1.3, attempting to execute a CTE would result
in an invalid "blank" SQL statement being executed; since this use case was
not working it now raises :class:`_exc.ObjectNotExecutableError`.
Previously, 1.4 was attempting to execute the CTE as a statement however it
was working only erratically.

The change also breaks out StatementRole from ReturnsRowsRole, as these
roles should not be in the same lineage (some statements don't return
rows, the whole class of ReturnsRows that are from clauses are
not statements).    Consolidate StatementRole and
CoerceTextStatementRole as there's no usage difference between
these.   Simplify some old tests that were trying to make
sure that "execution options" didn't transmit from a cte/subquery
out to a select; as cte/subuqery() aren't executable in any case
the options are removed.

Fixes: #6204
Change-Id: I62613b7ab418afdd22c409eae75659e3f52fb65f

Fixed regression where use of the :meth:`.Operators.in_` method with a
:class:`_sql.Select` object against a non-table-bound column would produce
an ``AttributeError``, or more generally using a :class:`_sql.ScalarSelect`
that has no datatype in a binary expression would produce invalid state.

Fixes: #6181
Change-Id: I1ddea433b3603fdab8f489bff571b512a6ffc66b

Implemented support for "table valued functions" along with additional
syntaxes supported by PostgreSQL, one of the most commonly requested
features. Table valued functions are SQL functions that return lists of
values or rows, and are prevalent in PostgreSQL in the area of JSON
functions, where the "table value" is commonly referred towards as the
"record" datatype. Table valued functions are also supported by Oracle and
SQL Server.

Moved from I5b093b72533ef695293e737eb75850b9713e5e03 due
to accidental push

Fixes: #3566
Change-Id: Iea36d04c80a5ed3509dcdd9ebf0701687143fef5

To prevent literal() from receiving a ClauseElement which
then leads to confusing results, add a new LiteralValueRole
coercion that does an _is_literal() check and implement
for literal().

Fixes: #5639
Change-Id: Ibd686544af2d7c013765278f984baf237de88caf

This reverts commit 05a31f2708590161d4b3b4c7ff65196c99b4a22b.

Atom has this little button called "push" and just pushes to master,
I wasn't even *on* master.  oops

WIP

Fixes: #3566
Change-Id: I5b093b72533ef695293e737eb75850b9713e5e03

Deprecation warnings are emitted under "SQLALCHEMY_WARN_20" mode when
passing a plain string to :meth:`_orm.Session.execute`.

It was also considered to have DDL string expressions to include
this as well, however this leaves us with no backwards-compatible
way of handling reflection of elemens, such as an Index() which
reflects "postgresql_where='x > 5'", there's no place for a rule
that will turn those into text() within the reflection process
that would be separate from when the user passes postgresql_where
to the Index.  Not worth it right now.

Fixes: #5754
Change-Id: I8673a79f0e87de0df576b655f39dad0351725ca8