Use temporary variable in initializer_list results with vialotion access error

Question

I am trying to use initializer_listto instantiate a class, but got a wired error.

When you try to create a `ClassB``variable using:

ClassB b = { { 1, {} }, { 2, {} };

A violation of access to memory will occur. However, if you change to:

ClassA a0, a1;
ClassB b = { { 1, a0 }, { 2, a1 } };

The error disappears.

I tried to compile VC 2013 (without update 1) and gcc-C ++ 4.8.1. Using gcc-C ++ 4.8.1 does not result in any runtime error. Is this a bug in VC?

Can anyone help confirm? Thank!

Below is the SSCCE:

#include <iostream>
#include <initializer_list>
#include <map>
#include <vector>
#include <memory>

using namespace std;

struct ClassA {
  struct Data {
    vector<int> vs;
  };
  unique_ptr<Data> d;

  ClassA() : d(new Data()) {}
  ClassA(const ClassA& a) : ClassA() {
    *d = *(a.d);
  }
};

struct ClassB {
  ClassB(initializer_list<pair<const int, ClassA> > v) { as = v; }
  map<int, ClassA> as;
};

int main() {
  ClassA a0, a1;
  // ClassB b = { { 1, a0 }, { 2, a1 } };     // won't crash in VC
  ClassB b = { { 1, {} }, { 2, {} } };
  return 0;
}

Answer 1

, unique_ptr , .

  unique_ptr<Data> d;

to

    Data * d;

:

    b.as.begin()->second.d->vs.push_back(1);

, () .