[Haskell-cafe] Disadvantages of de Bruijn indicies?

[Neil Mitchell]

Hi,

de Bruijn indicies look quite nice, and seem to eliminate a lot of
complexity when dealing with free variables:
http://en.wikipedia.org/wiki/De_Bruijn_index

So I was wondering, are they suitable for use in a compiler? If so,
what are their disadvantages/advantages? Is there any particular
reason that GHC (as an example) doesn't use them in its Core?

I'm trying to decide if I should use them in my compilers data type -
and would like some recommendations before I start.

Thanks

Neil