support quasiquoting for types
Currently, quasiquotes are limited to patterns and expressions, though patterns and expressions with explicit type signatures can be generated (with appropriate language flag for pattern signatures).
Since so much of Haskell programming happens at the type level, it would be great if quasiquoting wasn't excluded from that part of the game (think type-level numbers, for instance, or any type-level library that requires constants translated into types).
For just one example, see http://www.haskell.org/pipermail/haskell-cafe/2009-April/059819.html , where I would like to be able to specify label types and type tags directly at the type-level as well.
related: #1476 (closed) (Template Haskell won't address this in the near future, so having quasiquotes for types would narrow the gap)