gistfile1.cpp

#include <vector>
#include <boost/strong_typedef.hpp>

BOOST_STRONG_TYPEDEF(std::vector<std::vector<int>>, bitmap)
BOOST_STRONG_TYPEDEF(std::vector<std::vector<int>>, heightmap)

bitmap load_dog_sprite()
{
    return {};
}

heightmap get_level1_terrain()
{
    return {};
}

void render(const heightmap&, const bitmap&)
{
}

int main()
{
    // gcc: error: invalid initialization of reference of type ‘const heightmap&’ from expression of type ‘bitmap’
    // clang: note: candidate function not viable: no known conversion from 'bitmap' to 'const heightmap' for 1st argument
    render(load_dog_sprite(), get_level1_terrain());
    
    // ok
    render(get_level1_terrain(), load_dog_sprite());

    return 0;
}