Lambda 的"this"捕获返回垃圾

我正在实现自己的类，它提供其成员的延迟初始化。我遇到了一个奇怪的行为，在lambda中捕获this。

下面是一个重现这个错误的例子。

//Baz.h
#include <memory>
#include <functional>
#include "Lazy.hpp"
struct Foo
{
    std::string str;
    Foo() = default;
    Foo(std::string str) : str(str) {}
    Foo(Foo&& that) : str(that.str) {  }
};
class Baz
{
    std::string str;
    Lazy<std::unique_ptr<Foo>> foo;
public:
    Baz() = default;
    Baz(const std::string& str) : str(str)
    {
        //lazy 'this->foo' initialization. 
        //Is capturing of 'this' valid inside ctors???.
        this->foo = { [this] { return buildFoo(); } };
    }
    Baz(Baz&& that) : foo(std::move(that.foo)), str(that.str) { }
    std::string getStr() const
    {
        return this->foo.get()->str;
    }
private:
    std::unique_ptr<Foo> buildFoo()
    {
        //looks like 'this' points to nothing here.
        return std::make_unique<Foo>(str); //got error on this line
    }
};
int _tmain(int argc, _TCHAR* argv[])
{
    ///Variant 1 (lazy Foo inside regular Baz):
    Baz baz1("123");
    auto str1 = baz1.getStr();
    ///Variant 2 (lazy Foo inside lazy Baz):
    Lazy<Baz> lazy_baz = { [](){ return Baz("123"); } };
    auto& baz2 = lazy_baz.get(); //get() method returns 'inst' member (and initialize it if it's not initialized) see below
    auto str2 = baz2.getStr();
    return 0;
}

变量1工作良好。

变种2崩溃，出现以下错误:

lambda_this_capture_test.exe中0x642DF4CB (msvcr120.dll)的未处理异常:0xC0000005:访问冲突读取位置0x00E0FFFC.

我使用vc++120编译器(从VS2013)。

这是我的简化Lazy类:

#pragma once
#include <memory>
#include <atomic>
#include <mutex>
#include <functional>
#include <limits>
template<
    class T,
        typename = std::enable_if_t<
        std::is_move_constructible<T>::value &&
        std::is_default_constructible<T>::value
        >
>
class Lazy
{
    mutable std::unique_ptr<T> inst;
    std::function<T(void)> func;
    mutable std::atomic_bool initialized;
    mutable std::unique_ptr<std::mutex> mutex;
public:
    Lazy()
        : mutex(std::make_unique<std::mutex>())
        , func([]{ return T(); })
    {
        this->initialized.store(false);
    }
    Lazy(std::function<T(void)> func)
        : func(std::move(func))
        , mutex(std::make_unique<std::mutex>())
    {
        this->initialized.store(false);
    }
//... <move ctor + move operator>
    T& get() const
    {
        if (!initialized.load())
        {
            std::lock_guard<std::mutex> lock(*mutex);
            if (!initialized.load())
            {
                inst = std::make_unique<T>(func());
                initialized.store(true);
            }
        }
        return *inst;
    }
};

所以我的问题是:为什么这个例子会崩溃?它是有效的捕获this内部构造器?