Hi, I already mentioned this problem earlier on this mailing list, but now I have some extra information. It's the following (on GHCi): Prelude> :m Language.Haskell.Exts Prelude Language.Haskell.Exts> parseFileContents "main = putStrLn \"Hello World\"" Loading package array-0.5.0.0 ... linking ... done. Loading package filepath-1.3.0.2 ... linking ... done. Loading package deepseq-1.3.0.2 ... linking ... done. Loading package old-locale-1.0.0.6 ... linking ... done. Loading package time-1.4.2 ... linking ... done. Loading package bytestring-0.10.4.0 ... linking ... done. Loading package unix-2.7.0.1 ... linking ... done. Loading package directory-1.2.1.0 ... linking ... done. Loading package old-time-1.1.0.2 ... linking ... done. Loading package text-1.1.0.1 ... linking ... done. Loading package polyparse-1.9 ... linking ... done. Loading package cpphs-1.18.4 ... linking ... done. Loading package pretty-1.1.1.1 ... linking ... done. Loading package haskell-src-exts-1.15.0.1 ... linking ... done. Illegal instruction (core dumped) This affects everything that depends on haskell-src-exts, like hlint and stylish-haskell. The bug shows up only on my two AMD Athlon II X2 computers, but not on my other Intel Sandybridge. I think it is related to -fllvm flag because I didn't have this bug with the 1.15.0 version, which didn't have the flag. Can someone with similar AMD architecture try to replicate it, please? Thanks Nicola