Inlining Ref Functions

[dsimcha]

The fact that DMD does not inline functions with ref parameters has come up
several times deep in threads on this NG before, but it's never really
received proper attention.  After changing a few swaps in performance-critical
areas of my code to "manually inlined" swaps and seeing significant speedups,
I'm kind of curious what the rationale is for not inlining functions w/ ref
params.  Is there a good technical reason for this or is it simply a matter of
having higher priorities?  Is inlining functions w/ ref params on the "to do
eventually" list?