- The :meth:`.TypeEngine.with_variant` method will now accept a

type class as an argument which is internally converted to an
instance, using the same convention long established by other
constructs such as :class:`.Column`. fixes #3122

3 files changed, 17 insertions, 1 deletions

diff --git a/doc/build/changelog/changelog_09.rst b/doc/build/changelog/changelog_09.rst
index f6aa96a0f..6473da10b 100644
--- a/doc/build/changelog/changelog_09.rst
+++ b/doc/build/changelog/changelog_09.rst
@@ -15,6 +15,15 @@
     :released:
 
     .. change::
+        :tags: bug, sql
+        :tickets: 3122
+
+        The :meth:`.TypeEngine.with_variant` method will now accept a
+        type class as an argument which is internally converted to an
+        instance, using the same convention long established by other
+        constructs such as :class:`.Column`.
+
+    .. change::
         :tags: bug, orm
         :tickets: 3117
 
diff --git a/lib/sqlalchemy/sql/type_api.py b/lib/sqlalchemy/sql/type_api.py
index 6fa0bc64a..f9af21baa 100644
--- a/lib/sqlalchemy/sql/type_api.py
+++ b/lib/sqlalchemy/sql/type_api.py
@@ -263,7 +263,7 @@ class TypeEngine(Visitable):
         .. versionadded:: 0.7.2
 
         """
-        return Variant(self, {dialect_name: type_})
+        return Variant(self, {dialect_name: to_instance(type_)})
 
 
     @util.memoized_property
diff --git a/test/sql/test_types.py b/test/sql/test_types.py
index 1130c9e40..e5c1e7b62 100644
--- a/test/sql/test_types.py
+++ b/test/sql/test_types.py
@@ -816,6 +816,13 @@ class VariantTest(fixtures.TestBase, AssertsCompiledSQL):
             dialect=dialects.postgresql.dialect()
         )
 
+    def test_to_instance(self):
+        self.assert_compile(
+            self.UTypeOne().with_variant(self.UTypeTwo, "postgresql"),
+            "UTYPETWO",
+            dialect=dialects.postgresql.dialect()
+        )
+
     def test_compile_composite(self):
         self.assert_compile(
             self.composite,