chore: switch to cupy-stubs

pyproject.toml

@@ -61,6 +61,7 @@ test-min = [
 ]
 typecheck = [
   "array-api-compat!=1.15", # https://github.com/data-apis/array-api-compat/issues/436
+  "cupy-stubs",
   "mypy",
   "scipy-stubs",
   "sphinx",

src/fast_array_utils/stats/_power.py

@@ -47,7 +47,7 @@ def _power_array_api[A: AArray[object, object]](x: A, n: int, /, dtype: DTypeLik
 @_power.register(types.CSBase | types.CupyCSMatrix)
 def _power_cs[Mat: types.CSBase | types.CupyCSMatrix](x: Mat, n: int, /, dtype: DTypeLike | None = None) -> Mat:
     new_data = power(x.data, n, dtype=dtype)
-    return type(x)((new_data, x.indices, x.indptr), shape=x.shape, dtype=new_data.dtype)  # type: ignore[call-overload]
+    return type(x)((new_data, x.indices, x.indptr), shape=x.shape, dtype=new_data.dtype)  # type: ignore[arg-type]
 
 
 @_power.register(types.DaskArray)

tests/test_stats.py

@@ -253,13 +253,13 @@ def test_mean_var(
     mean, var = stats.mean_var(arr, axis=axis, correction=1)
     if isinstance(mean, types.DaskArray) and isinstance(var, types.DaskArray):
         mean, var = mean.compute(), var.compute()  # type: ignore[assignment]
-    if isinstance(mean, types.CupyArray) and isinstance(var, types.CupyArray):
-        mean, var = mean.get(), var.get()
+    # new names: `.get()` returns a less specific dtype than `mean` and `var` have
+    mean_np, var_np = (mean.get(), var.get()) if isinstance(mean, types.CupyArray) and isinstance(var, types.CupyArray) else (mean, var)
 
     mean_expected = np.mean(np_arr, axis=axis)
     var_expected = np.var(np_arr, axis=axis, ddof=1)
-    np.testing.assert_array_equal(mean, mean_expected)
-    np.testing.assert_array_almost_equal(var, var_expected)  # type: ignore[arg-type]
+    np.testing.assert_array_equal(mean_np, mean_expected)
+    np.testing.assert_array_almost_equal(var_np, var_expected)  # type: ignore[arg-type]
 
 
 @pytest.mark.skipif(not find_spec("sklearn"), reason="sklearn not installed")