atosed

struct MyStruct
{
    int i;
    string s;
}

mixin MixinParameters!MyStruct;

auto str(MyStruct m)
{
    import std.conv : to;

    return m.to!string;
}

assert(atosed!str(I(42)) == str(MyStruct(42, "")));
assert(atosed!str(S("42"), I(42)) == str(MyStruct(42, "42")));