4 files changed, 33 insertions, 12 deletions

diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py
index 09e38a5ab..423c3d446 100644
--- a/lib/sqlalchemy/sql/compiler.py
+++ b/lib/sqlalchemy/sql/compiler.py
@@ -34,6 +34,7 @@ import re
 from time import perf_counter
 import typing
 from typing import Any
+from typing import Callable
 from typing import Dict
 from typing import List
 from typing import Mapping
@@ -629,11 +630,11 @@ class SQLCompiler(Compiled):
     """list of columns that can be post-fetched after INSERT or UPDATE to
     receive server-updated values"""
 
-    insert_prefetch: Optional[List[Column[Any]]]
+    insert_prefetch: Sequence[Column[Any]] = ()
     """list of columns for which default values should be evaluated before
     an INSERT takes place"""
 
-    update_prefetch: Optional[List[Column[Any]]]
+    update_prefetch: Sequence[Column[Any]] = ()
     """list of columns for which onupdate default values should be evaluated
     before an UPDATE takes place"""
 
@@ -739,8 +740,6 @@ class SQLCompiler(Compiled):
     """if True, there are bindparam() objects that have the isoutparam
     flag set."""
 
-    insert_prefetch = update_prefetch = ()
-
     postfetch_lastrowid = False
     """if True, and this in insert, use cursor.lastrowid to populate
     result.inserted_primary_key. """
@@ -1340,7 +1339,7 @@ class SQLCompiler(Compiled):
         )
 
     @util.memoized_property
-    def _within_exec_param_key_getter(self):
+    def _within_exec_param_key_getter(self) -> Callable[[Any], str]:
         getter = self._key_getters_for_crud_column[2]
         if self.escaped_bind_names:
 
diff --git a/lib/sqlalchemy/sql/elements.py b/lib/sqlalchemy/sql/elements.py
index 4c38c4efa..168da17cc 100644
--- a/lib/sqlalchemy/sql/elements.py
+++ b/lib/sqlalchemy/sql/elements.py
@@ -58,12 +58,13 @@ from ..util.langhelpers import TypingOnly
 if typing.TYPE_CHECKING:
     from decimal import Decimal
 
+    from .compiler import Compiled
+    from .compiler import SQLCompiler
     from .operators import OperatorType
     from .selectable import FromClause
     from .selectable import Select
     from .sqltypes import Boolean  # noqa
     from .type_api import TypeEngine
-    from ..engine import Compiled
     from ..engine import Connection
     from ..engine import Dialect
     from ..engine import Engine
@@ -573,6 +574,25 @@ class ClauseElement(
             )
 
 
+class DQLDMLClauseElement(ClauseElement):
+    """represents a :class:`.ClauseElement` that compiles to a DQL or DML
+    expression, not DDL.
+
+    .. versionadded:: 2.0
+
+    """
+
+    if typing.TYPE_CHECKING:
+
+        def compile(  # noqa: A001
+            self,
+            bind: Optional[Union[Engine, Connection]] = None,
+            dialect: Optional[Dialect] = None,
+            **kw: Any,
+        ) -> SQLCompiler:
+            ...
+
+
 class CompilerColumnElement(
     roles.DMLColumnRole,
     roles.DDLConstraintColumnRole,
@@ -955,7 +975,7 @@ class ColumnElement(
     roles.DDLExpressionRole,
     SQLCoreOperations[_T],
     operators.ColumnOperators[SQLCoreOperations],
-    ClauseElement,
+    DQLDMLClauseElement,
 ):
     """Represent a column-oriented SQL expression suitable for usage in the
     "columns" clause, WHERE clause etc. of a statement.
@@ -1820,7 +1840,7 @@ class BindParameter(roles.InElementRole, ColumnElement[_T]):
         )
 
 
-class TypeClause(ClauseElement):
+class TypeClause(DQLDMLClauseElement):
     """Handle a type keyword in a SQL statement.
 
     Used by the ``Case`` statement.
@@ -1849,7 +1869,7 @@ class TextClause(
     roles.BinaryElementRole,
     roles.InElementRole,
     Executable,
-    ClauseElement,
+    DQLDMLClauseElement,
 ):
     """Represent a literal SQL text fragment.
 
@@ -2285,7 +2305,7 @@ class ClauseList(
     roles.OrderByRole,
     roles.ColumnsClauseRole,
     roles.DMLColumnRole,
-    ClauseElement,
+    DQLDMLClauseElement,
 ):
     """Describe a list of clauses, separated by an operator.
 
@@ -3205,7 +3225,7 @@ class IndexExpression(BinaryExpression):
     inherit_cache = True
 
 
-class GroupedElement(ClauseElement):
+class GroupedElement(DQLDMLClauseElement):
     """Represent any parenthesized expression"""
 
     __visit_name__ = "grouping"
diff --git a/lib/sqlalchemy/sql/schema.py b/lib/sqlalchemy/sql/schema.py
index fdae4d7b0..c270e1564 100644
--- a/lib/sqlalchemy/sql/schema.py
+++ b/lib/sqlalchemy/sql/schema.py
@@ -1131,6 +1131,7 @@ class Column(DialectKWArgs, SchemaItem, ColumnClause[_T]):
     __visit_name__ = "column"
 
     inherit_cache = True
+    key: str
 
     @overload
     def __init__(
diff --git a/lib/sqlalchemy/sql/selectable.py b/lib/sqlalchemy/sql/selectable.py
index a5cbffb5e..e5c2bef68 100644
--- a/lib/sqlalchemy/sql/selectable.py
+++ b/lib/sqlalchemy/sql/selectable.py
@@ -62,6 +62,7 @@ from .elements import ClauseElement
 from .elements import ClauseList
 from .elements import ColumnClause
 from .elements import ColumnElement
+from .elements import DQLDMLClauseElement
 from .elements import GroupedElement
 from .elements import Grouping
 from .elements import literal_column
@@ -85,7 +86,7 @@ class _OffsetLimitParam(BindParameter):
         return self.effective_value
 
 
-class ReturnsRows(roles.ReturnsRowsRole, ClauseElement):
+class ReturnsRows(roles.ReturnsRowsRole, DQLDMLClauseElement):
     """The base-most class for Core constructs that have some concept of
     columns that can represent rows.