use ExpressionElementRole for case targets in case()

Fixed regression where the :func:`_sql.text` construct would no longer be
accepted as a target case in the "whens" list within a :func:`_sql.case`
construct. The regression appears related to an attempt to guard against
some forms of literal values that were considered to be ambiguous when
passed here; however, there's no reason the target cases shouldn't be
interpreted as open-ended SQL expressions just like anywhere else, and a
literal string or tuple will be converted to a bound parameter as would be
the case elsewhere.

Fixes: #7287
Change-Id: I75478adfa115f3292cb1362cc5b2fdf152b0ed6f

1 files changed, 9 insertions, 0 deletions

diff --git a/test/sql/test_text.py b/test/sql/test_text.py
index 15f6f6048..4fff0ed7e 100644
--- a/test/sql/test_text.py
+++ b/test/sql/test_text.py
@@ -6,6 +6,7 @@ from sqlalchemy import bindparam
 from sqlalchemy import Column
 from sqlalchemy import desc
 from sqlalchemy import exc
+from sqlalchemy import extract
 from sqlalchemy import Float
 from sqlalchemy import func
 from sqlalchemy import Integer
@@ -182,6 +183,14 @@ class SelectCompositionTest(fixtures.TestBase, AssertsCompiledSQL):
             "(select f from bar where lala=heyhey) foo WHERE foo.f = t.id",
         )
 
+    def test_expression_element_role(self):
+        """test #7287"""
+
+        self.assert_compile(
+            extract("year", text("some_date + :param")),
+            "EXTRACT(year FROM some_date + :param)",
+        )
+
     @testing.combinations(
         (
             None,