DMD "preprocessed"-source output?

[Nick Sabalausky]

I don't suppose DMD has any way to output a copy of what the source files 
look like after things like mixins, CTFE and versions are applied? (Sort of 
like running a C compiler with a "preprocess-only" flag). I don't see 
anything like this in the listed command-line params, but maybe I missed it.

I have a program (that makes heavy use of mixins and CTFE and such) that 
gives wildly different output between two different versions of DMD/Tango 
(Tango's documented "breaking changes" don't appear to be the culprit and 
nothing in DMD's changelog or the latest bugzilla entries seem to 
immediately stick out). I'm sure I can track it down, but it would help to 
narrow things down if I could run the "preprocessed" results from both 
environments through a file diff.