https://issues.dlang.org/show_bug.cgi?id=13257
--- Comment #4 from Vladimir Panteleev <thecybersha...@gmail.com> --- I don't know if this is feasible as I guess it'd have to be replicated across many other ranges, but one possibility would be to make MapResult.back a template function. Then, it will only be instantiated when actually used by the map consumer. --
