Datatypes can take contexts. Currently TH dies if you try to reifyDecl a datatype with a context e.g. import Language.Haskell.THSyntax (runQ) data (Eq a) => Tree a = Leaf a | Branch (Tree a) (Tree a) main = do output <- runQ $ reifyDecl Tree putStr $ show output will cause the impossible to happen. I went in and changed DsMeta.hs to pass the cxt for reifyDecl (repTyClD for case TyData), which kept the impossible from happening, but then realized (at least partially) why it wasn't there before. THSyntax.Data doesn't support contexts. Except that a diagnostic rather than death would be preferable, is this an omission, on a todo list, or purposely left out? Also, is there a todo-list somewhere or a document with a fairly comprehensive listing of how far along the implementation is and known bugs? On a side note: why not toss up a TH page on the Haskell wiki, especially if the answer to my second question is no? _________________________________________________________________ The new MSN 8: advanced junk mail protection and 2 months FREE* http://join.msn.com/?page=features/junkmail