Use isfinite

Author: Daniel Saxton

pandas/core/arrays/categorical.py

@@ -520,7 +520,7 @@ def astype(self, dtype: Dtype, copy: bool = True) -> ArrayLike:
             if dtype == self.dtype:
                 return self
             return self._set_dtype(dtype)
-        if is_integer_dtype(dtype) and self.isin([np.nan, -np.inf, np.inf]).any():
+        if is_integer_dtype(dtype) and np.isfinite(self.__array__()).all():
             msg = "Cannot cast to int."
             raise ValueError(msg)
         return np.array(self, dtype=dtype, copy=copy)