1 files changed, 16 insertions, 12 deletions
diff --git a/alembic/autogenerate/compare.py b/alembic/autogenerate/compare.py
index 828a4cd..d97eb9c 100644
--- a/alembic/autogenerate/compare.py
+++ b/alembic/autogenerate/compare.py
@@ -17,6 +17,7 @@ from typing import Union
 from sqlalchemy import event
 from sqlalchemy import inspect
 from sqlalchemy import schema as sa_schema
+from sqlalchemy import text
 from sqlalchemy import types as sqltypes
 from sqlalchemy.util import OrderedSet
 
@@ -30,6 +31,7 @@ if TYPE_CHECKING:
 
     from sqlalchemy.engine.reflection import Inspector
     from sqlalchemy.sql.elements import quoted_name
+    from sqlalchemy.sql.elements import TextClause
     from sqlalchemy.sql.schema import Column
     from sqlalchemy.sql.schema import ForeignKeyConstraint
     from sqlalchemy.sql.schema import Index
@@ -37,6 +39,7 @@ if TYPE_CHECKING:
     from sqlalchemy.sql.schema import UniqueConstraint
 
     from alembic.autogenerate.api import AutogenContext
+    from alembic.ddl.impl import DefaultImpl
     from alembic.operations.ops import AlterColumnOp
     from alembic.operations.ops import MigrationScript
     from alembic.operations.ops import ModifyTableOps
@@ -276,14 +279,12 @@ def _compare_tables(
 
 
 def _make_index(params: Dict[str, Any], conn_table: Table) -> Optional[Index]:
-    exprs = []
-    for col_name in params["column_names"]:
+    exprs: list[Union[Column[Any], TextClause]] = []
+    for num, col_name in enumerate(params["column_names"]):
+        item: Union[Column[Any], TextClause]
         if col_name is None:
-            util.warn(
-                "Skipping reflected expression-based "
-                f"index {params['name']!r}"
-            )
-            return None
+            assert "expressions" in params
+            item = text(params["expressions"][num])
         else:
             item = conn_table.c[col_name]
         exprs.append(item)
@@ -439,10 +440,10 @@ class _uq_constraint_sig(_constraint_sig):
 class _ix_constraint_sig(_constraint_sig):
     is_index = True
 
-    def __init__(self, const: Index) -> None:
+    def __init__(self, const: Index, impl: DefaultImpl) -> None:
         self.const = const
         self.name = const.name
-        self.sig = tuple(sorted([col.name for col in const.columns]))
+        self.sig = impl.create_index_sig(const)
         self.is_unique = bool(const.unique)
 
     def md_name_to_sql_name(self, context: AutogenContext) -> Optional[str]:
@@ -624,11 +625,14 @@ def _compare_indexes_and_uniques(
         _uq_constraint_sig(uq) for uq in metadata_unique_constraints
     }
 
-    metadata_indexes_sig = {_ix_constraint_sig(ix) for ix in metadata_indexes}
+    impl = autogen_context.migration_context.impl
+    metadata_indexes_sig = {
+        _ix_constraint_sig(ix, impl) for ix in metadata_indexes
+    }
 
     conn_unique_constraints = {_uq_constraint_sig(uq) for uq in conn_uniques}
 
-    conn_indexes_sig = {_ix_constraint_sig(ix) for ix in conn_indexes}
+    conn_indexes_sig = {_ix_constraint_sig(ix, impl) for ix in conn_indexes}
 
     # 5. index things by name, for those objects that have names
     metadata_names = {
@@ -816,7 +820,7 @@ def _compare_indexes_and_uniques(
                 )
             if conn_obj.sig != metadata_obj.sig:
                 msg.append(
-                    " columns %r to %r" % (conn_obj.sig, metadata_obj.sig)
+                    " expression %r to %r" % (conn_obj.sig, metadata_obj.sig)
                 )
 
             if msg: