private static boolean isIndexVariableOnlyUsedAsIndex(
    @NotNull PsiVariable arrayVariable,
    @NotNull PsiVariable indexVariable,
    @Nullable PsiStatement body) {
    if (body == null) {
      return true;
    }
    final VariableOnlyUsedAsIndexVisitor visitor =
      new VariableOnlyUsedAsIndexVisitor(arrayVariable, indexVariable);
    body.accept(visitor);
    return visitor.isIndexVariableUsedOnlyAsIndex();
  }
private static boolean isIndexVariableOnlyUsedAsIndex(
    @NotNull PsiVariable arrayVariable,
    @NotNull PsiVariable indexVariable,
    @Nullable PsiStatement body)