More range woes: composed ranges are unsafe to return from functions

[jerro]

> Hmm. There *is* a delegate being passed to map(). Would that 
> cause
> problems? Theoretically it shouldn't, but as you said, if dmd 
> isn't
> handling it correctly that could cause problems.

I'm looking at the disassembly of cprod 
(http://pastebin.com/ngTax6B8) and there doesn't seem to be a 
call to _d_allocmemory in it. AFAIK it should be if the memory 
for the variables that the delegate uses was allocated on the 
heap?