message: Also compare the initial values with the loop values when checking loops for the same nested substructure. Tests coming soon.
diff: @@ -209,6 +209,7 @@ def _verify_tf_loop_vars(init_vars,
  shape_invariants)
  for name, init, entry, exit_, invariant in named_vars:
  try:
  + nest.assert_same_structure(init, entry, expand_composites=True)
  nest.assert_same_structure(entry, exit_, expand_composites=True)
  except (ValueError, TypeError) as e:
  raise TypeError('"{}" does not have the same nested structure after one'
  