diff --git a/mesonpy/_editable.py b/mesonpy/_editable.py
index f11b48af2..87d80f400 100644
--- a/mesonpy/_editable.py
+++ b/mesonpy/_editable.py
@@ -391,7 +391,7 @@ def _rebuild(self) -> Node:
 
     def _path_hook(self, path: str) -> MesonpyPathFinder:
         if os.altsep:
-            path.replace(os.altsep, os.sep)
+            path = path.replace(os.altsep, os.sep)
         path, _, key = path.rpartition(os.sep)
         if path == __file__:
             tree = self._rebuild()