1 files changed, 24 insertions, 0 deletions
diff --git a/lib/sqlalchemy/sql/roles.py b/lib/sqlalchemy/sql/roles.py
index 2d3aaf903..053bd7146 100644
--- a/lib/sqlalchemy/sql/roles.py
+++ b/lib/sqlalchemy/sql/roles.py
@@ -100,6 +100,30 @@ class FromClauseRole(ColumnsClauseRole):
         raise NotImplementedError()
 
 
+class StrictFromClauseRole(FromClauseRole):
+    # does not allow text() or select() objects
+    pass
+
+
+class AnonymizedFromClauseRole(StrictFromClauseRole):
+    # calls .alias() as a post processor
+
+    def _anonymous_fromclause(self, name=None, flat=False):
+        """A synonym for ``.alias()`` that is only present on objects of this
+        role.
+
+        This is an implicit assurance of the target object being part of the
+        role where anonymous aliasing without any warnings is allowed,
+        as opposed to other kinds of SELECT objects that may or may not have
+        an ``.alias()`` method.
+
+        The method is used by the ORM but is currently semi-private to
+        preserve forwards-compatibility.
+
+        """
+        return self.alias(name=name, flat=flat)
+
+
 class CoerceTextStatementRole(SQLRole):
     _role_name = "Executable SQL, text() construct, or string statement"