java - OpenJML がサイクルでアサーションを証明できないのはなぜですか?

Question

次のコードがあります。

//@ requires dest != null;
//@ requires srcOff >= 0;
//@ requires destOff >= 0;
//@ requires length >= 0;
//@ requires srcOff < src.length;
//@ requires destOff < dest.length;
//@ requires srcOff + length <= src.length;
//@ requires destOff + length <= dest.length;
//@ ensures dest != null;
//@ ensures src != null;
//@ ensures \old(length) == length;
//@ ensures \old(dest.length) == dest.length;
//@ ensures (\forall int j; 0 <= j && j < length; dest[destOff+j] == src[srcOff+j]);
private static void arraycopy(int[] src,
                              int   srcOff,
                              int[] dest,
                              int   destOff,
                              int   length) {
  int i = 0;                              
  for(i=0 ; i<length; i=i+1) {
    //@ assert length >= 0;
    //@ assert i < length;
    //@ assert i >= 0;
    //@ assert destOff + i >= 0;
    //@ assert srcOff + i >= 0;
    //@ assert destOff + i < dest.length;
    //@ assert srcOff + i < src.length;
    dest[destOff+i] = src[srcOff+i];
  }
}

ここにいくつかの OpenJML 注釈を挿入しました。ターミナルで OpenJML を実行すると、次のエラーが表示されます。

$ jml -esc MultiSet.java 
MultiSet.java:120: warning: The prover cannot establish an assertion (Postcondition: MultiSet.java:119: ) in method arraycopy
  private static void arraycopy(int[] src,
                      ^
MultiSet.java:119: warning: Associated declaration: MultiSet.java:120: 
  //@ ensures (\forall int j; 0 <= j && j < length; dest[destOff+j] == src[srcOff+j]);
      ^
MultiSet.java:129: warning: The prover cannot establish an assertion (Assert) in method arraycopy
      //@ assert i >= 0;
          ^
3 warnings

\forallサイクルと//@ assert i >= 0;アサーションが機能しない理由が本当にわかりません。彼らは私には大丈夫に見えます。