code: func (c *Changes) PlannedState(prior *states.State) (*states.State, error) {
  	panic("Changes.PlannedState not yet implemented")
  }
docs: // PlannedState merges the set of changes described by the receiver into the
  // given prior state to produce the planned result state.
  //
  // The result is an approximation of the state as it would exist after
  // applying these changes, omitting any values that cannot be determined until
  // the changes are actually applied.