Using GHC 7.8.3 from the latest Haskell Platform on OS X 10.9.4, the __GLASGOW_HASKELL__ preprocessor symbol is being set to 708 instead of 783. I'd guess I have some stale files lying from previous versions GHC or HP, but I can't seem to find them. Any clues? $ cat wtf.hs {-# LANGUAGE CPP #-} $ ghc-7.8.3 -v -E wtf.hs 2>&1 | grep 708 /usr/bin/gcc -E -undef -traditional -Wno-invalid-pp-token -Wno-unicode -Wno-trigraphs -I /Library/Frameworks/GHC.framework/Versions/7.8.3-x86_64/usr/lib/ghc-7.8.3/base-4.7.0.1/include -I /Library/Frameworks/GHC.framework/Versions/7.8.3-x86_64/usr/lib/ghc-7.8.3/integer-gmp-0.5.1.0/include -I /Library/Frameworks/GHC.framework/Versions/7.8.3-x86_64/usr/lib/ghc-7.8.3/include '-D__GLASGOW_HASKELL__=708' '-Ddarwin_BUILD_OS=1' '-Dx86_64_BUILD_ARCH=1' '-Ddarwin_HOST_OS=1' '-Dx86_64_HOST_ARCH=1' -U__PIC__ -D__PIC__ '-D__SSE__=1' '-D__SSE2__=1' -x assembler-with-cpp wtf.hs -o /var/folders/w7/_cxvr2k540163p59kwvqlzrc0000gn/T/ghc14288_0/ghc14288_1.hscpp Thanks, Greg