#include <iostream>
 
struct foobar {
    foobar( int a, int b ) {
        std::cout << "foobar created with " << a << " " << b << "\n";
    }
};
 
struct barbaz {
    barbaz( int a ) {
        std::cout << "barbaz created with " << a << "\n";
    }
};
 
template <typename T>
auto make( int a, int b ) -> decltype( T( a ,b ) ) {
    return T( a, b );
}
 
template <typename T>
auto make( int a, int b ) -> decltype( T( a ) ) {
    return T( a );
}
 
int main() {
    auto x = make<foobar>( 10, 42 );
    auto y = make<barbaz>( 10, 42 );
}
 

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