Remove all remaining removed_in_20 warnings slated for removal

Finalize all remaining removed-in-2.0 changes so that we
can begin doing pep-484 typing without old things
getting in the way (we will also have to do public_factory).

note there are a few "moved_in_20()" and "became_legacy_in_20()"
warnings still in place.  The SQLALCHEMY_WARN_20 variable
is now removed.

Also removed here are the legacy "in place mutators" for Select
statements, and some keyword-only argument signatures in Core
have been added.

Also in the big change department, the ORM mapper() function
is removed entirely; the Mapper class is otherwise unchanged,
just the public-facing API function.  Mappers are now always
given a registry in which to participate, however the
argument signature of Mapper is not changed. ideally "registry"
would be the first positional argument.

Fixes: #7257

Change-Id: Ic70c57b9f1cf7eb996338af5183b11bdeb3e1623

1 files changed, 2 insertions, 20 deletions

diff --git a/lib/sqlalchemy/sql/elements.py b/lib/sqlalchemy/sql/elements.py
index 6e5fbba88..3ec702e10 100644
--- a/lib/sqlalchemy/sql/elements.py
+++ b/lib/sqlalchemy/sql/elements.py
@@ -2785,10 +2785,7 @@ class Case(ColumnElement):
         ("else_", InternalTraversal.dp_clauseelement),
     ]
 
-    # TODO: for Py2k removal, this will be:
-    # def __init__(self, *whens, value=None, else_=None):
-
-    def __init__(self, *whens, **kw):
+    def __init__(self, *whens, value=None, else_=None):
         r"""Produce a ``CASE`` expression.
 
         The ``CASE`` construct in SQL is a conditional object that
@@ -2875,8 +2872,7 @@ class Case(ColumnElement):
          whether or not :paramref:`.case.value` is used.
 
          .. versionchanged:: 1.4 the :func:`_sql.case`
-            function now accepts the series of WHEN conditions positionally;
-            passing the expressions within a list is deprecated.
+            function now accepts the series of WHEN conditions positionally
 
          In the first form, it accepts a list of 2-tuples; each 2-tuple
          consists of ``(<sql expression>, <value>)``, where the SQL
@@ -2911,24 +2907,14 @@ class Case(ColumnElement):
 
         """
 
-        if "whens" in kw:
-            util.warn_deprecated_20(
-                'The "whens" argument to case() is now passed using '
-                "positional style only, not as a keyword argument."
-            )
-            whens = (kw.pop("whens"),)
-
         whens = coercions._expression_collection_was_a_list(
             "whens", "case", whens
         )
-
         try:
             whens = util.dictlike_iteritems(whens)
         except TypeError:
             pass
 
-        value = kw.pop("value", None)
-
         whenlist = [
             (
                 coercions.expect(
@@ -2954,15 +2940,11 @@ class Case(ColumnElement):
         self.type = type_
         self.whens = whenlist
 
-        else_ = kw.pop("else_", None)
         if else_ is not None:
             self.else_ = coercions.expect(roles.ExpressionElementRole, else_)
         else:
             self.else_ = None
 
-        if kw:
-            raise TypeError("unknown arguments: %s" % (", ".join(sorted(kw))))
-
     @property
     def _from_objects(self):
         return list(