Templates don't always guess initializer list types

#include <initializer_list>
#include <utility>

void foo(std::initializer_list<std::pair<int,int>>) {}
template <class T> void bar(T) {}

int main() {
    foo({{0,1}});  //This works
    foo({{0,1},{1,2}});  //This works
    bar({{0,1}});  //This warns
    bar({{0,1},{1,2}});  //This fails
    bar(std::initializer_list<std::pair<int,int>>({{0,1},{1,2}}));  //This works
}

This doesn't compile in gcc 4.5.3, it gives a warning for the marked line saying deducing ‘T’ as ‘std::initializer_list<std::initializer_list<int> >’ and an error for the marked line saying no matching function for call to ‘bar(<brace-enclosed initializer list>)’. Why can gcc deduce the type of the first call to bar but not the second, and is there a way to fix this other than long and ugly casting?