plum Parametric return types not working

Hi! I'm getting some warnings about return types for subclasses of Generic and is says to open an issue...

The error is approximately


class Object(Generic[T]):
    def method(self) -> T: ...

class A(): ...

@dispatch
def function(...) -> Object[A]: ...

The error is

UserWarning: Could not resolve the type hint of `coordinax._src.vectors.collection.core.KinematicSpace[coordinax._src.vectors.d3.cylindrical.CylindricalPos]`. I have ended the resolution here to not make your code break, but some types might not be working correctly. Please open an issue at https://github.com/beartype/plum.

The full problem can be found in the CI for https://github.com/GalacticDynamics/coordinax/pull/443.

Jul 01 '25 17:07 nstarman

GH isn't letting me attach this doc so here's a snippet

Details

2025-07-01T17:40:32.2249438Z 2025-07-01T17:40:32.2250023Z 2025-07-01T17:40:32.2250231Z 2025-07-01T17:40:32.2251037Z 2025-07-01T17:40:32.2251528Z 2025-07-01T17:40:32.2252925Z 2025-07-01T17:40:32.2254043Z 2025-07-01T17:40:32.2254392Z 2025-07-01T17:40:32.2262668Z 2025-07-01T17:40:32.2263839Z 2025-07-01T17:40:32.2265447Z 2025-07-01T17:40:32.2266826Z 2025-07-01T17:40:32.2267381Z 2025-07-01T17:40:32.2268348Z 2025-07-01T17:40:32.2269308Z 2025-07-01T17:40:32.2269785Z 2025-07-01T17:40:32.2270722Z 2025-07-01T17:40:32.2271686Z 2025-07-01T17:40:32.2272190Z 2025-07-01T17:40:32.2273446Z 2025-07-01T17:40:32.2274509Z 2025-07-01T17:40:32.2275025Z 2025-07-01T17:40:32.2276084Z 2025-07-01T17:40:32.2277111Z 2025-07-01T17:40:32.2277482Z 2025-07-01T17:40:32.2278320Z 2025-07-01T17:40:32.2279184Z 2025-07-01T17:40:32.2279604Z 2025-07-01T17:40:32.2280539Z 2025-07-01T17:40:32.2281604Z 2025-07-01T17:40:32.2282174Z 2025-07-01T17:40:32.2283337Z 2025-07-01T17:40:32.2284279Z 2025-07-01T17:40:32.2284735Z 2025-07-01T17:40:32.2285661Z 2025-07-01T17:40:32.2286641Z 2025-07-01T17:40:32.2287130Z 2025-07-01T17:40:32.2288061Z 2025-07-01T17:40:32.2289066Z 2025-07-01T17:40:32.2289589Z 2025-07-01T17:40:32.2290585Z 2025-07-01T17:40:32.2291629Z 2025-07-01T17:40:32.2292132Z 2025-07-01T17:40:32.2293361Z 2025-07-01T17:40:32.2294342Z 2025-07-01T17:40:32.2294652Z 2025-07-01T17:40:32.2295566Z 2025-07-01T17:40:32.2296619Z 2025-07-01T17:40:32.2297359Z 2025-07-01T17:40:32.2298615Z 2025-07-01T17:40:32.2299669Z 2025-07-01T17:40:32.2300069Z 2025-07-01T17:40:32.2301285Z 2025-07-01T17:40:32.2302707Z 2025-07-01T17:40:32.2303228Z 2025-07-01T17:40:32.2304186Z 2025-07-01T17:40:32.2305214Z 2025-07-01T17:40:32.2305795Z 2025-07-01T17:40:32.2306881Z 2025-07-01T17:40:32.2307925Z 2025-07-01T17:40:32.2309077Z 2025-07-01T17:40:32.2310235Z 2025-07-01T17:40:32.2310774Z 2025-07-01T17:40:32.2311720Z 2025-07-01T17:40:32.2312894Z 2025-07-01T17:40:32.2313399Z 2025-07-01T17:40:32.2314439Z 2025-07-01T17:40:32.2315532Z 2025-07-01T17:40:32.2316063Z 2025-07-01T17:40:32.2317062Z 2025-07-01T17:40:32.2318000Z 2025-07-01T17:40:32.2319966Z tests/test_package.py [32m.[0m[31m [100%][0m =================================== FAILURES =================================== [31m[1m____________________ frame_transforms.py line=186 column=1 _____________________[0m Example at /home/runner/work/coordinax/coordinax/src/coordinax/_coordinax_space_frames/frame_transforms.py, line 186, column 1 did not evaluate as expected: Exception raised: Traceback (most recent call last): File "/home/runner/.local/share/uv/python/cpython-3.11.13-linux-x86_64-gnu/lib/python3.11/doctest.py", line 1355, in __run exec(compile(example.source, filename, "single", File "<doctest /home/runner/work/coordinax/coordinax/src/coordinax/coordinax_space_frames/frame_transforms.py[0]>", line 1, in vega_q = cx.vecs.LonLatSphericalPos.from(vega.icrs.data) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/runner/work/coordinax/coordinax/.venv/lib/python3.11/site-packages/plum/function.py", line 509, in call return self._f(self._instance, *args, **kw_args) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/runner/work/coordinax/coordinax/.venv/lib/python3.11/site-packages/plum/function.py", line 383, in call return _convert(method(*args, **kw_args), return_type) ^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/runner/work/coordinax/coordinax/.venv/lib/python3.11/site-packages/jaxtyping/_decorator.py", line 549, in wrapped_fn return wrapped_fn_impl(args, kwargs, bound, memos) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/runner/work/coordinax/coordinax/.venv/lib/python3.11/site-packages/jaxtyping/_decorator.py", line 473, in wrapped_fn_impl out = fn(*args, **kwargs) ^^^^^^^^^^^^^^^^^^^ File "/home/runner/work/coordinax/coordinax/src/coordinax/src/vectors/base/vector.py", line 612, in from return vector(cls, *args, **kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/runner/work/coordinax/coordinax/.venv/lib/python3.11/site-packages/plum/function.py", line 383, in call return _convert(method(*args, **kw_args), return_type) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/runner/work/coordinax/coordinax/.venv/lib/python3.11/site-packages/plum/function.py", line 42, in _convert return _promised_convert(obj, target_type) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/runner/work/coordinax/coordinax/.venv/lib/python3.11/site-packages/plum/function.py", line 383, in call return _convert(method(*args, **kw_args), return_type) ^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/runner/work/coordinax/coordinax/.venv/lib/python3.11/site-packages/plum/promotion.py", line 49, in convert return _convert.invoke(type(obj), type_to)(obj, type_to) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/runner/work/coordinax/coordinax/.venv/lib/python3.11/site-packages/plum/function.py", line 433, in wrapped_method return _convert(method(*args, **kw_args), return_type) ^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/runner/work/coordinax/coordinax/.venv/lib/python3.11/site-packages/plum/promotion.py", line 83, in perform_conversion return f(obj) ^^^^^^ File "/home/runner/work/coordinax/coordinax/.venv/lib/python3.11/site-packages/jaxtyping/_decorator.py", line 549, in wrapped_fn return wrapped_fn_impl(args, kwargs, bound, memos) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/runner/work/coordinax/coordinax/.venv/lib/python3.11/site-packages/jaxtyping/_decorator.py", line 473, in wrapped_fn_impl out = fn(*args, **kwargs) ^^^^^^^^^^^^^^^^^^^ File "/home/runner/work/coordinax/coordinax/src/coordinax/_src/vectors/d3/register_convert.py", line 147, in convert_math_spherical_to_lonlat_spherical return vconvert(LonLatSphericalPos, pos) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/runner/work/coordinax/coordinax/.venv/lib/python3.11/site-packages/plum/function.py", line 382, in call method, return_type = self._resolve_method_with_cache(args=args) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/runner/work/coordinax/coordinax/.venv/lib/python3.11/site-packages/plum/function.py", line 399, in _resolve_method_with_cache self._resolve_pending_registrations() File "/home/runner/work/coordinax/coordinax/.venv/lib/python3.11/site-packages/plum/function.py", line 288, in _resolve_pending_registrations submethod = Method(f, subsignature, function_name=self.name) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/runner/work/coordinax/coordinax/.venv/lib/python3.11/site-packages/plum/method.py", line 49, in init return_type = extract_return_type(implementation) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/runner/work/coordinax/coordinax/.venv/lib/python3.11/site-packages/plum/method.py", line 222, in extract_return_type return_type = resolve_type_hint(sig.return_annotation) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/runner/work/coordinax/coordinax/.venv/lib/python3.11/site-packages/plum/type.py", line 238, in resolve_type_hint warnings.warn( UserWarning: Could not resolve the type hint of coordinax._src.vectors.collection.core.KinematicSpace[coordinax._src.vectors.d3.cylindrical.CylindricalPos]. I have ended the resolution here to not make your code break, but some types might not be working correctly. Please open an issue at https://github.com/beartype/plum.

Jul 01 '25 21:07 nstarman

Hey @nstarman! Generics unfortunately aren't yet supported in this way, which is why you're seeing the warning. :( Perhaps we should specialise the warning so that it says this.

I might soon have capacity to more actively start working on this again. Perhaps seeing if generics in this way could be supported would be a good thing to do first.

Jul 04 '25 12:07 wesselb

Thanks @wesselb, that would be great. I'd love to be using plum with Generic types. Especially in return annotations.

Jul 21 '25 19:07 nstarman