RFC: template-haskell & Data.Map vs. Prelude.lookup use

[Herbert Valerio Riedel]

Hello *,

In order to address

  https://github.com/haskell/cabal/issues/1811

I've prepared a commit for review at

  https://git.haskell.org/ghc.git/commitdiff/refs/heads/wip/drop-containers-dep-from-th


However, I'm wondering if we really need Data.Map, or if would be
equally ok to simply use  O(n) Prelude.lookup-style dictionary

Does anyone here happen to have an estimate for how large the dictionary
in

  https://git.haskell.org/ghc.git/blob/HEAD:/libraries/template-haskell/Language/Haskell/TH/PprLib.hs#l120

(which is the only use of Data.Map in TH) typically gets?

Cheers,
  hvr