[BUG] Importing `cuda_models` breaks StructModel usage

[brandon-b-miller]

importing import numba.cuda.datamodel.cuda_models as models causes subsequent kernel launches to fail.

from numba import cuda
from numba.cuda.types import int64, void
import numba.cuda.datamodel.cuda_models as models

@cuda.jit(void(int64[::1]))
def kernel(ary):
    print(ary[0])

TypeError: Not a structure model: <numba.cuda.datamodel.cuda_models.ArrayModel object at 0x7f95349116a0>

This appears to be due to a conflict between the numba.cuda StructModel class and the upstream version in a place they're not meant to coexist. It's possible that the module redirector hasn't had time to replace the values in the models namespace before something is being registered from the upstream namespace.

[gmarkall]

You should not import cuda_models directly, and you are indeed getting in front of the redirector by doing this. If you want the models from Numba-CUDA, you should do

from numba import cuda
from numba.cuda.types import int64, void
from numba.cuda.datamodel import models

@cuda.jit(void(int64[::1]))
def kernel(ary):
    print(ary[0])