Set correct type annotations for ColumnElement.cast

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Fixes: #9156
### Description
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### Checklist
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This pull request is:

- [ ] A documentation / typographical error fix
	- Good to go, no issue or tests are needed
- [x] A short code fix
	- please include the issue number, and create an issue if none exists, which
	  must include a complete example of the issue.  one line code fixes without an
	  issue and demonstration will not be accepted.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.   one line code fixes without tests will not be accepted.
- [ ] A new feature implementation
	- please include the issue number, and create an issue if none exists, which must
	  include a complete example of how the feature would look.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.

**Have a nice day!**

Closes: #9157
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/9157
Pull-request-sha: 321dac184ee0d317296a689d7c8e47bf1464bcce

Change-Id: I99fe759a21de910f34bae3bb919e82cd08969e81

diff --git a/doc/build/changelog/unreleased_20/9156.rst b/doc/build/changelog/unreleased_20/9156.rst
new file mode 100644 (file)
index 0000000..9fbeb44
--- /dev/null
+++ b/doc/build/changelog/unreleased_20/9156.rst
@@ -0,0 +1,7 @@
+.. change::
+    :tags: bug, typing
+    :tickets: 9156
+
+    The :meth:`_expression.ColumnElement.cast` is typed to accept
+    both ``Type[TypeEngine[T]]`` and ``TypeEngine[T]`` rather only
+    ``TypeEngine[T]``.
\ No newline at end of file

diff --git a/lib/sqlalchemy/sql/elements.py b/lib/sqlalchemy/sql/elements.py
index 71d8cb2d329a39f2134a4334921554d3d376965c..c3f7b884ce2245d4b8a61e8543293e9efdc91aa5 100644 (file)
--- a/lib/sqlalchemy/sql/elements.py
+++ b/lib/sqlalchemy/sql/elements.py
@@ -1641,7 +1641,7 @@ class ColumnElement(
             co._is_clone_of = selectable._is_clone_of.columns.get(key)
         return key, co
 
-    def cast(self, type_: TypeEngine[_T]) -> Cast[_T]:
+    def cast(self, type_: _TypeEngineArgument[_T]) -> Cast[_T]:
         """Produce a type cast, i.e. ``CAST(<expression> AS <type>)``.
 
         This is a shortcut to the :func:`_expression.cast` function.

diff --git a/test/ext/mypy/plugin_files/issue_9156.py b/test/ext/mypy/plugin_files/issue_9156.py
new file mode 100644 (file)
index 0000000..46e5e95
--- /dev/null
+++ b/test/ext/mypy/plugin_files/issue_9156.py
@@ -0,0 +1,11 @@
+from typing import Any, Type
+
+from sqlalchemy.sql.elements import ColumnElement
+from sqlalchemy.sql.type_api import TypeEngine
+
+col: ColumnElement[Any]
+type_: Type[TypeEngine[Any]]
+obj: TypeEngine[Any]
+
+col.cast(type_)
+col.cast(obj)