remove 2.0-removed Query elements

* :meth:`_orm.Query.join` no longer accepts the "aliased" and
"from_joinpoint" arguments

* :meth:`_orm.Query.join` no longer accepts chains of multiple join
targets in one method call.

* ``Query.from_self()`` and ``Query.with_polymorphic()``
are removed.

Change-Id: I534d04b53a538a4fc374966eb2bc8eb98a16497d
References: #7257

3 files changed, 16 insertions, 31 deletions

diff --git a/lib/sqlalchemy/sql/coercions.py b/lib/sqlalchemy/sql/coercions.py
index fa21fbeef..1a0336c67 100644
--- a/lib/sqlalchemy/sql/coercions.py
+++ b/lib/sqlalchemy/sql/coercions.py
@@ -606,22 +606,15 @@ class InElementImpl(RoleImpl):
             return element
 
 
-class OnClauseImpl(_CoerceLiterals, _ColumnCoercions, RoleImpl):
+class OnClauseImpl(_ColumnCoercions, RoleImpl):
     __slots__ = ()
 
     _coerce_consts = True
 
-    def _text_coercion(self, element, argname=None, legacy=False):
-        if legacy and isinstance(element, str):
-            util.warn_deprecated_20(
-                "Using strings to indicate relationship names in "
-                "Query.join() is deprecated and will be removed in "
-                "SQLAlchemy 2.0.  Please use the class-bound attribute "
-                "directly."
-            )
-            return element
-
-        return super(OnClauseImpl, self)._text_coercion(element, argname)
+    def _literal_coercion(
+        self, element, name=None, type_=None, argname=None, is_crud=False, **kw
+    ):
+        self._raise_for_expected(element)
 
     def _post_coercion(self, resolved, original_element=None, **kw):
         # this is a hack right now as we want to use coercion on an
@@ -936,8 +929,6 @@ class JoinTargetImpl(RoleImpl):
             # #6550, unless JoinTargetImpl._skip_clauseelement_for_target_match
             # were set to False.
             return original_element
-        elif legacy and isinstance(resolved, roles.WhereHavingRole):
-            return resolved
         elif legacy and resolved._is_select_statement:
             util.warn_deprecated(
                 "Implicit coercion of SELECT and textual SELECT "
diff --git a/lib/sqlalchemy/sql/roles.py b/lib/sqlalchemy/sql/roles.py
index 1f6a8ddf2..f076f1092 100644
--- a/lib/sqlalchemy/sql/roles.py
+++ b/lib/sqlalchemy/sql/roles.py
@@ -120,7 +120,10 @@ class StatementOptionRole(StructuralRole):
 
 class OnClauseRole(AllowsLambdaRole, StructuralRole):
     __slots__ = ()
-    _role_name = "SQL expression for ON clause"
+    _role_name = (
+        "ON clause, typically a SQL expression or "
+        "ORM relationship attribute"
+    )
 
 
 class WhereHavingRole(OnClauseRole):
diff --git a/lib/sqlalchemy/sql/selectable.py b/lib/sqlalchemy/sql/selectable.py
index 8b35dc6ac..b53235a83 100644
--- a/lib/sqlalchemy/sql/selectable.py
+++ b/lib/sqlalchemy/sql/selectable.py
@@ -4636,7 +4636,7 @@ class SelectState(util.MemoizedSlots, CompileState):
 class _SelectFromElements:
     def _iterate_from_elements(self):
         # note this does not include elements
-        # in _setup_joins or _legacy_setup_joins
+        # in _setup_joins
 
         seen = set()
         for element in self._raw_columns:
@@ -4666,7 +4666,6 @@ class _MemoizedSelectEntities(
     _traverse_internals = [
         ("_raw_columns", InternalTraversal.dp_clauseelement_list),
         ("_setup_joins", InternalTraversal.dp_setup_join_tuple),
-        ("_legacy_setup_joins", InternalTraversal.dp_setup_join_tuple),
         ("_with_options", InternalTraversal.dp_executable_options),
     ]
 
@@ -4680,22 +4679,15 @@ class _MemoizedSelectEntities(
 
     @classmethod
     def _generate_for_statement(cls, select_stmt):
-        if (
-            select_stmt._setup_joins
-            or select_stmt._legacy_setup_joins
-            or select_stmt._with_options
-        ):
+        if select_stmt._setup_joins or select_stmt._with_options:
             self = _MemoizedSelectEntities()
             self._raw_columns = select_stmt._raw_columns
             self._setup_joins = select_stmt._setup_joins
-            self._legacy_setup_joins = select_stmt._legacy_setup_joins
             self._with_options = select_stmt._with_options
 
             select_stmt._memoized_select_entities += (self,)
             select_stmt._raw_columns = (
                 select_stmt._setup_joins
-            ) = (
-                select_stmt._legacy_setup_joins
             ) = select_stmt._with_options = ()
 
 
@@ -4730,7 +4722,6 @@ class Select(
     __visit_name__ = "select"
 
     _setup_joins = ()
-    _legacy_setup_joins = ()
     _memoized_select_entities = ()
 
     _distinct = False
@@ -4757,7 +4748,6 @@ class Select(
             ("_order_by_clauses", InternalTraversal.dp_clauseelement_tuple),
             ("_group_by_clauses", InternalTraversal.dp_clauseelement_tuple),
             ("_setup_joins", InternalTraversal.dp_setup_join_tuple),
-            ("_legacy_setup_joins", InternalTraversal.dp_setup_join_tuple),
             ("_correlate", InternalTraversal.dp_clauseelement_tuple),
             ("_correlate_except", InternalTraversal.dp_clauseelement_tuple),
             ("_limit_clause", InternalTraversal.dp_clauseelement),
@@ -4921,7 +4911,7 @@ class Select(
 
     @_generative
     def join(
-        self: SelfSelect, target, onclause=None, isouter=False, full=False
+        self: SelfSelect, target, onclause=None, *, isouter=False, full=False
     ) -> SelfSelect:
         r"""Create a SQL JOIN against this :class:`_expression.Select`
         object's criterion
@@ -4990,7 +4980,7 @@ class Select(
         )
         return self
 
-    def outerjoin_from(self, from_, target, onclause=None, full=False):
+    def outerjoin_from(self, from_, target, onclause=None, *, full=False):
         r"""Create a SQL LEFT OUTER JOIN against this :class:`_expression.Select`
         object's criterion
         and apply generatively, returning the newly resulting
@@ -5009,8 +4999,9 @@ class Select(
         from_,
         target,
         onclause=None,
+        *,
         isouter=False,
-        full=False,
+        full=False
     ) -> SelfSelect:
         r"""Create a SQL JOIN against this :class:`_expression.Select`
         object's criterion
@@ -5071,7 +5062,7 @@ class Select(
         )
         return self
 
-    def outerjoin(self, target, onclause=None, full=False):
+    def outerjoin(self, target, onclause=None, *, full=False):
         """Create a left outer join.
 
         Parameters are the same as that of :meth:`_expression.Select.join`.