TODO Issue 4725: Remove when sum is standard in Phobos.
assert([1, 2, 3, 4].sum == 10);
http://d.puremagic.com/issues/show_bug.cgi?id=4725
https://github.com/D-Programming-Language/phobos/pull/1205
http://forum.dlang.org/thread/bug-4725-3@http.d.puremagic.com%2Fissues%2F
See Implementation
TODO Issue 4725: Remove when sum is standard in Phobos.