c++ template casting with derived classes

Question

``` #include struct A {int a;}; struct B : public A {char b;}; int main() { B b; typedef std::pair MyPair; std::vector v; v.push_back(std::make_pair(&b, &b)); //compiler error should be here(pair) return 0; } ``` I don't understand why this compiles (maybe somebody can kindly provide detailed explanation? Is it something related to name look-up? Btw, on Solaris, SunStudio12 it doesn't compile: `error : formal argument x of type const std::pair & in call to std::vector >::push_back(const std::pair & ) is being passed std::pair`

Accepted Answer

`std::pair` has a constructor template: ``` template pair(const pair &p); ``` "Effects: Initializes members from the corresponding members of the argument, performing implicit conversions as needed." (C++03, 20.2.2/4) Conversion from a derived class pointer to a base class pointer is implicit.

c++ template casting with derived classes

Solution

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