diff options
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/GHC/Driver/Make.hs | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/compiler/GHC/Driver/Make.hs b/compiler/GHC/Driver/Make.hs index 7f740f0123..362303a5c8 100644 --- a/compiler/GHC/Driver/Make.hs +++ b/compiler/GHC/Driver/Make.hs @@ -1255,8 +1255,6 @@ function GHC.IfaceToCore.typecheckIface does exactly that. Following this fix, GHC can compile itself with --make -O2. -} --- NB: sometimes mods has duplicates; this is harmless because --- any duplicates get clobbered in addListToHpt and never get forced. typecheckLoop :: HscEnv -> [HomeModInfo] -> IO [(ModuleName, HomeModInfo)] typecheckLoop hsc_env hmis = do debugTraceMsg logger 2 $ @@ -1265,6 +1263,7 @@ typecheckLoop hsc_env hmis = do let new_hpt = addListToHpt old_hpt new_mods let new_hsc_env = hscUpdateHPT (const new_hpt) hsc_env -- Crucial, crucial: initIfaceLoad clears the if_rec_types field. + -- See [KnotVars invariants] mds <- initIfaceLoad new_hsc_env $ mapM (typecheckIface . hm_iface) hmis let new_mods = [ (mn,hmi{ hm_details = details }) @@ -1274,7 +1273,10 @@ typecheckLoop hsc_env hmis = do where logger = hsc_logger hsc_env - old_hpt = hsc_HPT hsc_env + to_delete = (map (moduleName . mi_module . hm_iface) hmis) + -- Filter out old modules before tying the knot, otherwise we can end + -- up with a thunk which keeps reference to the old HomeModInfo. + !old_hpt = foldl' delFromHpt (hsc_HPT hsc_env) to_delete -- --------------------------------------------------------------------------- -- |