diff --git a/mercurial/posix.py b/mercurial/posix.py
--- a/mercurial/posix.py
+++ b/mercurial/posix.py
@@ -323,7 +323,10 @@
                     fullpath = os.path.join(cachedir, target)
                     open(fullpath, b'w').close()
                 except IOError as inst:
-                    if inst[0] == errno.EACCES:
+                    if (
+                        inst[0]  # pytype: disable=unsupported-operands
+                        == errno.EACCES
+                    ):
                         # If we can't write to cachedir, just pretend
                         # that the fs is readonly and by association
                         # that the fs won't support symlinks. This