#8528: Preprocessor issues building GHC HEAD on Mavericks ----------------------------------------+---------------------------------- Reporter: guest | Owner: Type: bug | Status: new Priority: high | Milestone: Component: Compiler | Version: 7.7 Resolution: | Keywords: clang Operating System: MacOS X | Architecture: x86_64 (amd64) Type of failure: Building GHC failed | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: #8480 ----------------------------------------+---------------------------------- Comment (by hvr): Btw, deciding whether Alex is to blame or rather GHC, and how to actually *fix* the situation really depends on what the formal specification for `{-# LANGUAGE CPP #-}` actually is... but I couldn't find any :-/ The way I understand it, Haskell code on Hackage using CPP seems to have implicitly assumed for several years that http://gcc.gnu.org/onlinedocs/cpp/Traditional-Mode.html is the underlying CPP model. However, Clang's cpp obviously implements different semantics and/or doesn't implement traditional mode at all. So this actually a much larger issue, and it isn't enough to just patch code to compile with both Clang's cpp and GCC's cpp (and hope it doesn't break again, as developers generally don't have both cpp implementation available for testing) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8528#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler