Passing an empty tensor (so with shape (0,n,m)) to pack_padded_sequence causes a "segmentation fault (core dumped)"

Produce the error:

import torch
from torch.nn.utils.rnn import pack_padded_sequence
#bs, max_sequence_len, emb_dim
x = torch.zeros([16,10,20])
length = torch.zeros([16])
mask = [length != 0]
masked_x = x[mask]
masked_length = length[mask]
print(masked_x.shape, masked_length.shape)
pack_padded_sequence(masked_x, masked_length, batch_first = True)

Expected behavior:
An exception raised stating that the input tensor must not be empty.

Environments created on:
-PyTorch 1.0, Windows (installed via conda), CUDA (9.0)
-PyTorch 1.0, Linux (installed via pip), CUDA ('9.0.176')

Thanks,
Jamie