at::Tensor a = torch:tensor({1, 2,3});
at::Tensor b = torch:tensor({4});
std::vector<torch::jit::IValue> inputs;
inputs.push_back(a);
inputs.push_back(b);
auto out = moModel.forward(inputs).toTensor();

This should work if you just want to pass two tensors to forward(). The issue you are mentioning is specific for named tensors/tuples