@NotNull
  @Override
  public Iterable<Instruction> predecessors(@NotNull CallEnvironment environment) {
    final Deque<CallInstruction> stack = environment.callStack(this);
    for (Instruction instruction : myPredecessors) {
      environment.update(stack, instruction);
    }
    return myPredecessors;
  }
@NotNull
  @Override
  public Iterable<Instruction> predecessors(@NotNull CallEnvironment environment)