rvalue to lvalue conversion Visual Studio

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A temporary object of class type is still an object. It lives somewhere in memory, which means that there’s nothing unusual in the compiler being able to attach a reference to it. At physical level whether it is a const reference or non-const reference makes no difference. In other words, in cases like that the language restriction is purely conceptual, artificial. The compiler simply ignores that restriction. There’s no need to “transform” anything here. The reference is simply attached directly to the object, wherever that object happens to reside.

Basically, for a class that provides the outside word with access to the value of its this pointer (or with lvalue access to *this) the behavior can be immediately and easily simulated 

struct S {
  S& get_lvalue() { return *this; }
};

void foo(S& s);
...

foo(S().get_lvalue());

The above code is perfectly legal and it works around the aforementioned restriction. You can think of MSVC++ behavior as being equivalent to this.

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