- 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

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,