describe mypy-related limitation

README.md

@@ -93,6 +93,28 @@ tedious. The `signature-mutators` directive will globally disable the
 signature-checking for `aioretry()` and `retry()` calls, so this can be easier
 depending of your own usage of kaioretry.)
 
+## Mypy and functions generated by kaioretry.aioretry
+
+[Mypy](https://github.com/python/mypy) may incorrectly infer the type of an
+aioretry-decorated function as `def (*Any, **Any) -> Any` *if* the original
+function:
+
+1. is a coroutine _and_
+2. has a returned type hinted as `Any` and/or if parameters are hinted as `Any`.
+
+If the original function is fully annotated as non-`Any`, the resulting
+decorated function annotations should be correctly inferred (according to
+[kaioretry test](/Anvil/kaioretry/main/test/static_analysis)).
+
+It is unclear to me right now, if the `kaioretry.aioretry` function type hints
+are incorrect or if it is an issue with either mypy or cpython. Or both. Or
+all 3. Go figure.
+
+Any information on that matter would be greatly appreciated. I've spent weeks
+trying to track down this issue. And while walking down this path has allowed
+me to fix some other (rather unrelated) type-hinting boo-boos from my part,
+this very specific issue is still puzzling me.
+
 # Feedback welcome.
 
 Always.