VM_Interface._assert(bufferOffset(tail).sGE(VM_Offset.fromInt(arity<<LOG_BYTES_IN_ADDRESS)));
VM_Interface._assert(bufferOffset(tail).sGE(VM_Word.fromIntZeroExtend(arity).lsh(LOG_BYTES_IN_ADDRESS).toOffset()));
  protected final void checkInsert(int arity) throws VM_PragmaInline {    if (bufferOffset(tail).isZero())      insertOverflow(arity);    else if (VM_Interface.VerifyAssertions)      VM_Interface._assert(bufferOffset(tail).sGE(VM_Offset.fromInt(arity<<LOG_BYTES_IN_ADDRESS)));  }