Repro. Fails with not-so-readable error message

import torch
@torch.jit.script
def mm(x, y):
    return x @ y

x = torch.randn(4, 3)
y = torch.randn(3, 2)
mm(x, y)

Traceback

We should either support it or ask people to use torch.mm

cc @zdevito

I'll try to take a stab at this sometime if this is the correct diagnosis