Add IndexDomain

1 files changed, 7 insertions, 0 deletions

diff --git a/sphinx/environment/collectors/indexentries.py b/sphinx/environment/collectors/indexentries.py
index 9c86779fc..640eb915b 100644
--- a/sphinx/environment/collectors/indexentries.py
+++ b/sphinx/environment/collectors/indexentries.py
@@ -8,22 +8,29 @@
     :license: BSD, see LICENSE for details.
 """
 
+import warnings
 from typing import Any, Dict, Set
 
 from docutils import nodes
 
 from sphinx import addnodes
 from sphinx.application import Sphinx
+from sphinx.deprecation import RemovedInSphinx40Warning
 from sphinx.environment import BuildEnvironment
 from sphinx.environment.collectors import EnvironmentCollector
 from sphinx.util import split_index_msg, logging
 
+
 logger = logging.getLogger(__name__)
 
 
 class IndexEntriesCollector(EnvironmentCollector):
     name = 'indices'
 
+    def __init__(self) -> None:
+        warnings.warn('IndexEntriesCollector is deprecated.',
+                      RemovedInSphinx40Warning)
+
     def clear_doc(self, app: Sphinx, env: BuildEnvironment, docname: str) -> None:
         env.indexentries.pop(docname, None)