Improve static typing in ``intersphinx`` et al

2 files changed, 9 insertions, 4 deletions

diff --git a/sphinx/util/inventory.py b/sphinx/util/inventory.py
index a879a17dd..123a86d25 100644
--- a/sphinx/util/inventory.py
+++ b/sphinx/util/inventory.py
@@ -7,7 +7,7 @@ import zlib
 from typing import IO, TYPE_CHECKING, Callable, Iterator
 
 from sphinx.util import logging
-from sphinx.util.typing import Inventory
+from sphinx.util.typing import Inventory, InventoryItem
 
 BUFSIZE = 16 * 1024
 logger = logging.getLogger(__name__)
@@ -133,8 +133,8 @@ class InventoryFile:
             if location.endswith('$'):
                 location = location[:-1] + name
             location = join(uri, location)
-            invdata.setdefault(type, {})[name] = (projname, version,
-                                                  location, dispname)
+            inv_item: InventoryItem = projname, version, location, dispname
+            invdata.setdefault(type, {})[name] = inv_item
         return invdata
 
     @classmethod
diff --git a/sphinx/util/typing.py b/sphinx/util/typing.py
index 3f2acb822..d4e87ef1d 100644
--- a/sphinx/util/typing.py
+++ b/sphinx/util/typing.py
@@ -51,7 +51,12 @@ OptionSpec = Dict[str, Callable[[str], Any]]
 TitleGetter = Callable[[nodes.Node], str]
 
 # inventory data on memory
-InventoryItem = Tuple[str, str, str, str]
+InventoryItem = Tuple[
+    str,  # project name
+    str,  # project version
+    str,  # URL
+    str,  # display name
+]
 Inventory = Dict[str, Dict[str, InventoryItem]]