I'm facing this problem only when I compiled the code using -O2 Flag. I tried the following, * Compiled with -O1 Flag (7.4.1), It compiled fine * Compiled with ghc-7.0.4 with -O2, it's getting compiled successfully but with the Warning, SpecConstr Function `$wa{v s27vx} [lid]' has one call pattern, but the limit is ... [Module that is getting stuck is using heavy quasiquotation] Env: OS: Ubuntu 12.04 [x86_64] GHC: 7.4.1 Is this a bug? Anything else should I need to try?