Numba nopython模式下调用np.hstack出现类型错误的问题求助

我最近在Numba的nopython模式下编译一个简单函数时遇到了问题，代码如下：

from numba import njit
import numpy as np

@njit
def fun(x,y):
    points = np.hstack((x,y))
    return points

a = 5
b = 2
res = fun(a,b)

这段代码去掉@njit装饰器后能正常运行，但加上装饰器就会抛出TypingError，报错信息如下：

TypingError: Failed in nopython mode pipeline (step: nopython frontend)
No implementation of function Function(<function hstack at 0x7f491475fe50>) found for signature:

hstack(UniTuple(int64 x 2))

There are 4 candidate implementations:

• Of which 4 did not match due to:
  Overload in function '_OverloadWrapper._build..ol_generated': File: numba/core/overload_glue.py: Line 129.
  With argument(s): '(UniTuple(int64 x 2))':
  Rejected as the implementation raised a specific error:
  TypeError: np.hstack(): expecting a non-empty tuple of arrays, got UniTuple(int64 x 2)
  raised from /usr/local/lib/python3.8/dist-packages/numba/core/typing/npydecl.py:748

During: resolving callee type: Function(<function hstack at 0x7f491475fe50>)
During: typing of call at (28)

File "", line 28:
def fun(x, y):
points = np.hstack((x, y))
^

我还尝试了传入一个标量和一个数组的情况（这也是我实际业务场景中会遇到的情况），结果还是报错：

修改后的调用代码：

b = np.ones(3)
res = fun(a,b)

对应的报错信息：

TypingError: Failed in nopython mode pipeline (step: nopython frontend)
No implementation of function Function(<function hstack at 0x7f491475fe50>) found for signature:

hstack(Tuple(int64, array(float64, 1d, C)))

There are 4 candidate implementations:

• Of which 4 did not match due to:
  Overload in function '_OverloadWrapper._build..ol_generated': File: numba/core/overload_glue.py: Line 129.
  With argument(s): '(Tuple(int64, array(float64, 1d, C)))':
  Rejected as the implementation raised a specific error:
  TypeError: np.hstack(): expecting a non-empty tuple of arrays, got Tuple(int64, array(float64, 1d, C))
  raised from /usr/local/lib/python3.8/dist-packages/numba/core/typing/npydecl.py:748

During: resolving callee type: Function(<function hstack at 0x7f491475fe50>)
During: typing of call at (28)

File "", line 28:
def fun(x, y):
points = np.hstack((x, y))

而且我发现np.concatenate也有类似的问题，这真的让我很困惑。我现在使用的是Numba 0.56.4版本（应该是当时的稳定版），有没有大佬能给我一些解决建议？非常感谢！

备注：内容来源于stack exchange，提问作者FDP