diff --git a/scrapy/pipelines/files.py b/scrapy/pipelines/files.py
index a5948525a..6a32c8b47 100644
--- a/scrapy/pipelines/files.py
+++ b/scrapy/pipelines/files.py
@@ -36,7 +36,7 @@ from scrapy.utils.request import referer_str
 logger = logging.getLogger(__name__)
 
 
-def _to_string(path: Union[str, os.PathLike]):
+def _to_string(path: Union[str, os.PathLike[str]]):
     return str(path)  # convert a Path object to string
 
 
@@ -45,7 +45,7 @@ class FileException(Exception):
 
 
 class FSFilesStore:
-    def __init__(self, basedir: Union[str, os.PathLike]):
+    def __init__(self, basedir: Union[str, os.PathLike[str]]):
         basedir = _to_string(basedir)
         if '://' in basedir:
             basedir = basedir.split('://', 1)[1]
@@ -70,7 +70,7 @@ class FSFilesStore:
 
         return {'last_modified': last_modified, 'checksum': checksum}
 
-    def _get_filesystem_path(self, path: Union[str, os.PathLike]) -> Path:
+    def _get_filesystem_path(self, path: Union[str, os.PathLike[str]]) -> Path:
         path_comps = _to_string(path).split('/')
         return Path(self.basedir, *path_comps)