rakudo/rakudo — pull request #175 by leedo (2013-07-02 16:04:48+00:00)
Title: optimization for sum metaop on a Range

This seems to work with my limited testing locally.

TimToady said:

11:01 < TimToady> lee_: there's something a little wrong with it in regards to flattening, since a range in list context
flattens, but you're kinda bypassing the flattening, such that [+] $range would "flatten" $range when it
shouldn't, seems to me

But I'm not sure I understand.