decltype deduces wrong type by jensa79

#include <vector>


struct Int
{
explicit Int(int);



};


Int intfunc(Int, Int);

template<typename FwdIt, typename Func, typename T>
auto foldl(FwdIt first, FwdIt last, Func f, T initial) ->
decltype(f(initial, *first))
{
for(; first != last; ++first)
{
     initial = f(initial, *first);
}


return initial;



}


// instantiate template to check compilation
void instantiate()
{
std::vector<Int> v;

Int x3 = foldl(v.begin(), v.end(), intfunc, Int(0));
Int x4 = foldl(v.cbegin(), v.cend(), intfunc, Int(0));



}


When I compile this on VC++2010, I get warning:
Warning 1     warning C4172: returning address of local variable or
temporary     c:\users\jensa\desktop\vs2010bug\foldl\foldl\foldl.cpp 18
Warning 2     warning C4172: returning address of local variable or
temporary     c:\users\jensa\desktop\vs2010bug\foldl\foldl\foldl.cpp 18