crash calling .solve() on an assembly with no constraints

[greyltc]

line 139, in main
    asy.solve()
  File "/usr/lib/python3.9/site-packages/cadquery/assembly.py", line 408, in solve
    locs_new = solver.solve()
  File "/usr/lib/python3.9/site-packages/cadquery/occ_impl/solver.py", line 212, in solve
    res = minimize(
  File "/usr/lib/python3.9/site-packages/scipy/optimize/_minimize.py", line 614, in minimize
    return _minimize_bfgs(fun, x0, args, jac, callback, **options)
  File "/usr/lib/python3.9/site-packages/scipy/optimize/optimize.py", line 1164, in _minimize_bfgs
    gnorm = vecnorm(gfk, ord=norm)
  File "/usr/lib/python3.9/site-packages/scipy/optimize/optimize.py", line 166, in vecnorm
    return np.amax(np.abs(x))
  File "<__array_function__ internals>", line 5, in amax
  File "/usr/lib/python3.9/site-packages/numpy/core/fromnumeric.py", line 2705, in amax
    return _wrapreduction(a, np.maximum, 'max', axis, None, out,
  File "/usr/lib/python3.9/site-packages/numpy/core/fromnumeric.py", line 87, in _wrapreduction
    return ufunc.reduce(obj, axis, dtype, out, **passkwargs)
ValueError: zero-size array to reduction operation maximum which has no identity