Does torchscript not support torch.nn.utils.rnn.pack_sequence?
Here’s a minimal example of what isn’t working on my computer:
import torch


class Test(torch.nn.Module):

	def forward(self):
		# return torch.tensor(1)
		sequences = [torch.randn(torch.randint(1,5,(1,)),3) for i in range(10)]
		packed = torch.nn.utils.rnn.pack_sequence(sequences, enforce_sorted=False)


model = Test()
model()
print("successfully called normal model")

try:
	tsModel = torch.jit.script(model)
	print("Successfully converted model")
except Exception as e:
	print("Failed to convert torchscript model!")
	print(e)

This code outputs the following for me:
successfully called normal model
Failed to convert torchscript model!

Tried to access nonexistent attribute or method 'new' of type 'Tensor'.:
  File "/home/jack/.pyenv/versions/3.7.0/lib/python3.7/site-packages/torch/nn/utils/rnn.py", line 365
        out_dims = (max_len, len(sequences)) + trailing_dims

    out_tensor = sequences[0].data.new(*out_dims).fill_(padding_value)
                 ~~~~~~~~~~~~~~~~~~~~ <--- HERE
    for i, tensor in enumerate(sequences):
        length = tensor.size(0)
'pad_sequence' is being compiled since it was called from 'pack_sequence'
  File "/home/jack/.pyenv/versions/3.7.0/lib/python3.7/site-packages/torch/nn/utils/rnn.py", line 409
    """
    lengths = [v.size(0) for v in sequences]
    return pack_padded_sequence(pad_sequence(sequences), lengths, enforce_sorted=enforce_sorted)
                                ~~~~~~~~~~~~~~~~~~~~~~ <--- HERE
'pack_sequence' is being compiled since it was called from 'Test.forward'
  File "test.py", line 9
		# return torch.tensor(1)
		sequences = [torch.randn(torch.randint(1,5,(1,)),3) for i in range(10)]
		packed = torch.nn.utils.rnn.pack_sequence(sequences, enforce_sorted=False)
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ <--- HERE