pep-484: session, instancestate, etc

Also adds some fixes to annotation-based mapping
that have come up, as well as starts to add more
pep-484 test cases

Change-Id: Ia722bbbc7967a11b23b66c8084eb61df9d233fee

4 files changed, 18 insertions, 7 deletions

diff --git a/lib/sqlalchemy/sql/_typing.py b/lib/sqlalchemy/sql/_typing.py
index bc1e0672c..7e3a1c4e8 100644
--- a/lib/sqlalchemy/sql/_typing.py
+++ b/lib/sqlalchemy/sql/_typing.py
@@ -7,6 +7,7 @@ from typing import TYPE_CHECKING
 from typing import TypeVar
 from typing import Union
 
+from sqlalchemy.sql.base import Executable
 from . import roles
 from .. import util
 from ..inspection import Inspectable
@@ -183,10 +184,14 @@ if TYPE_CHECKING:
     def is_table_value_type(t: TypeEngine[Any]) -> TypeGuard[TableValueType]:
         ...
 
-    def is_select_base(t: ReturnsRows) -> TypeGuard[SelectBase]:
+    def is_select_base(
+        t: Union[Executable, ReturnsRows]
+    ) -> TypeGuard[SelectBase]:
         ...
 
-    def is_select_statement(t: ReturnsRows) -> TypeGuard[Select]:
+    def is_select_statement(
+        t: Union[Executable, ReturnsRows]
+    ) -> TypeGuard[Select]:
         ...
 
     def is_table(t: FromClause) -> TypeGuard[TableClause]:
diff --git a/lib/sqlalchemy/sql/base.py b/lib/sqlalchemy/sql/base.py
index 7fb9c2602..ccd5e8c40 100644
--- a/lib/sqlalchemy/sql/base.py
+++ b/lib/sqlalchemy/sql/base.py
@@ -648,7 +648,9 @@ class CompileState:
             return None
 
     @classmethod
-    def _get_plugin_class_for_plugin(cls, statement, plugin_name):
+    def _get_plugin_class_for_plugin(
+        cls, statement: Executable, plugin_name: str
+    ) -> Optional[Type[CompileState]]:
         try:
             return cls.plugins[
                 (plugin_name, statement._effective_plugin_target)
@@ -790,7 +792,7 @@ class Options(metaclass=_MetaOptions):
         )
 
     @classmethod
-    def isinstance(cls, klass):
+    def isinstance(cls, klass: Type[Any]) -> bool:
         return issubclass(cls, klass)
 
     @hybridmethod
@@ -912,6 +914,8 @@ class ExecutableOption(HasCopyInternals):
 
     _is_has_cache_key = False
 
+    _is_core = True
+
     def _clone(self, **kw):
         """Create a shallow copy of this ExecutableOption."""
         c = self.__class__.__new__(self.__class__)
diff --git a/lib/sqlalchemy/sql/coercions.py b/lib/sqlalchemy/sql/coercions.py
index 4c71ca38b..623bb0be2 100644
--- a/lib/sqlalchemy/sql/coercions.py
+++ b/lib/sqlalchemy/sql/coercions.py
@@ -114,7 +114,7 @@ def _deep_is_literal(element):
                 schema.SchemaEventTarget,
                 HasCacheKey,
                 Options,
-                util.langhelpers._symbol,
+                util.langhelpers.symbol,
             ),
         )
         and not hasattr(element, "__clause_element__")
diff --git a/lib/sqlalchemy/sql/selectable.py b/lib/sqlalchemy/sql/selectable.py
index d7cc32733..99a6baa89 100644
--- a/lib/sqlalchemy/sql/selectable.py
+++ b/lib/sqlalchemy/sql/selectable.py
@@ -3037,7 +3037,9 @@ class ForUpdateArg(ClauseElement):
     skip_locked: bool
 
     @classmethod
-    def _from_argument(cls, with_for_update):
+    def _from_argument(
+        cls, with_for_update: Union[ForUpdateArg, None, bool, Dict[str, Any]]
+    ) -> Optional[ForUpdateArg]:
         if isinstance(with_for_update, ForUpdateArg):
             return with_for_update
         elif with_for_update in (None, False):
@@ -3045,7 +3047,7 @@ class ForUpdateArg(ClauseElement):
         elif with_for_update is True:
             return ForUpdateArg()
         else:
-            return ForUpdateArg(**with_for_update)
+            return ForUpdateArg(**cast("Dict[str, Any]", with_for_update))
 
     def __eq__(self, other):
         return (