diff --git a/tests/test-check-module-imports.t b/tests/test-check-module-imports.t
--- a/tests/test-check-module-imports.t
+++ b/tests/test-check-module-imports.t
@@ -43,3 +43,10 @@ will likely receive warnings about a dir
   > -X tests/test-verify-repo-operations.py \
   > -X tests/test-extension.t \
   > | sed 's-\\-/-g' | "$PYTHON" "$import_checker" -
+
+All files that get type checked must have 'from __future__ import annotations'
+
+  $ testrepohg files 'set:**.py and size(">0")' -I mercurial -I hgext -X mercurial/thirdparty -0 \
+  > | xargs -0 grep -L '^from __future__ import annotations$'
+  mercurial/cmd_impls/graft.py
+  mercurial/testing/ps_util.py