I'm goofing with TH and I have my program mostly done: http://hpaste.org/10713 If I have the "$(deriveBinary ''MyData)" line commented out it prints out what looks to me like correct code. I can even paste it into a program and it compiles. However, when the line isn't commented out I get an error I don't understand: test.hs:1:0: Illegal data constructor name: `x' When splicing generated code into the program There are two places in my code I use "x" in splices that could be causing the problem: g <- [| getWord8 >>= \x -> $(caseE [| x |] gcases') |] and put x = $(caseE [| x |] (map return ps)) |] but I don't understand why these might be causing errors (if they are indeed the cause). Using -ddump-splices doesn't help since it seems to hit the error before dumping splices. What's going on here? Tim Newsham http://www.thenewsh.com/~newsham/