I’m not sure if it’s the indexing or rather the rhs of the assignment, since the error says:

Expected a value of type ‘Tensor’ for argument ‘values’ but instead found type ‘int’.

This seems to work:
@torch.jit.script 
def f(): 
    t = torch.tensor([0.])
    t[t!=t] = torch.tensor(7.)
    return t

f()