Fix Trac #68: Turn on compilation via C for Template Haskell packages

We can't use HscNothing if we need to run code coming from modules inside
the processed package during typechecking, which is the case for some packages
using Template Haskell. This could be improved, to e.g. use HscInterpreted and
HscNothing where possible, instead of using HscC for all modules in the
package.

1 files changed, 14 insertions, 1 deletions

diff --git a/src/Haddock/Interface.hs b/src/Haddock/Interface.hs
index 8f8399df..aa77e042 100644
--- a/src/Haddock/Interface.hs
+++ b/src/Haddock/Interface.hs
@@ -86,7 +86,20 @@ createInterfaces' modules flags instIfaceMap = do
   targets <- mapM (\f -> guessTarget f Nothing) modules
   setTargets targets
   modgraph <- depanal [] False
-  let orderedMods = flattenSCCs $ topSortModuleGraph False modgraph Nothing
+
+  -- If template haskell is used by the package, we can not use
+  -- HscNothing as target since we might need to run code generated from
+  -- one or more of the modules during typechecking.
+  modgraph' <- if needsTemplateHaskell modgraph
+       then do
+         dflags <- getSessionDynFlags
+         setSessionDynFlags dflags { hscTarget = HscC } 
+         -- we need to set HscC on all the ModSummaries as well
+         let addHscC m = m { ms_hspp_opts = (ms_hspp_opts m) { hscTarget = HscC } }  
+         return (map addHscC modgraph)
+       else return modgraph
+
+  let orderedMods = flattenSCCs $ topSortModuleGraph False modgraph' Nothing
   (ifaces, _) <- foldM (\(ifaces, modMap) modsum -> do
     x <- processModule modsum flags modMap instIfaceMap
 #else