lint

8 files changed, 23 insertions, 21 deletions

diff --git a/compiler/basicTypes/Module.hs b/compiler/basicTypes/Module.hs
index a8c6244742..f9fc9c1560 100644
--- a/compiler/basicTypes/Module.hs
+++ b/compiler/basicTypes/Module.hs
@@ -123,7 +123,7 @@ module Module
         lookupWithDefaultModuleEnv, mapModuleEnv, mkModuleEnv, emptyModuleEnv,
         moduleEnvKeys, moduleEnvElts, moduleEnvToList,
         unitModuleEnv, isEmptyModuleEnv,
-        extendModuleEnvWith, 
+        extendModuleEnvWith,
 
         -- * ModuleName mappings
         ModuleNameEnv, DModuleNameEnv,
@@ -1251,7 +1251,7 @@ mkModuleSet :: [Module] -> ModuleSet
 mkModuleSet = mkFsSet
 
 extendModuleSet :: ModuleSet -> Module -> ModuleSet
-extendModuleSet = addOneToFsSet 
+extendModuleSet = addOneToFsSet
 
 extendModuleSetList :: ModuleSet -> [Module] -> ModuleSet
 extendModuleSetList = addListToFsSet
@@ -1291,4 +1291,5 @@ type ModuleNameEnv elt = FastStringEnv elt
 
 -- | A map keyed off of 'ModuleName's (actually, their 'Unique's)
 -- Has deterministic folds and can be deterministically converted to a list
-type DModuleNameEnv elt = DFastStringEnv elt
\ No newline at end of file
+type DModuleNameEnv elt = DFastStringEnv elt
+
diff --git a/compiler/llvmGen/LlvmCodeGen/Regs.hs b/compiler/llvmGen/LlvmCodeGen/Regs.hs
index 79e25359bc..0d2d6bf746 100644
--- a/compiler/llvmGen/LlvmCodeGen/Regs.hs
+++ b/compiler/llvmGen/LlvmCodeGen/Regs.hs
@@ -98,7 +98,7 @@ alwaysLive = [BaseReg, Sp, Hp, SpLim, HpLim, node]
 
 -- | STG Type Based Alias Analysis hierarchy
 stgTBAA :: Monad m => (FastString -> m Unique) -> m [(Unique, LMString, Maybe Unique)]
-stgTBAA m = undefined 
+stgTBAA m = undefined
 {-
   = return [ (rootN,  fsLit "root",   Nothing)
     , (topN,   fsLit "top",   Just rootN)
diff --git a/compiler/main/Annotations.hs b/compiler/main/Annotations.hs
index 6090a37ea6..55e0abb974 100644
--- a/compiler/main/Annotations.hs
+++ b/compiler/main/Annotations.hs
@@ -125,7 +125,7 @@ findAnns deserialize (MkAnnEnv ann_env)
 --   only transient annotations will be returned.
 findAnnsByTypeRep :: AnnEnv Name -> CoreAnnTarget -> TypeRep -> [[Word8]]
 findAnnsByTypeRep (MkAnnEnv ann_env) target tyrep
-  = [ ws | Serialized tyrep' ws <- Map.findWithDefault [] target ann_env 
+  = [ ws | Serialized tyrep' ws <- Map.findWithDefault [] target ann_env
     , tyrep' == tyrep ]
 
 -- | Deserialize all annotations of a given type. This happens lazily, that is
diff --git a/compiler/main/Packages.hs b/compiler/main/Packages.hs
index 4ffe348696..04084dfff7 100644
--- a/compiler/main/Packages.hs
+++ b/compiler/main/Packages.hs
@@ -1479,7 +1479,7 @@ mkPackageState dflags dbs preload0 = do
         case compareByPreference prec_map unit unit' of
             GT -> (fs, unit)
             _  -> (fs, unit')
-      addIfMorePreferable m unit = 
+      addIfMorePreferable m unit =
           let fs = fsPackageName unit
           in addToUDFM_C preferLater m (FastStringU fs) (fs, unit)
       -- This is the set of maximally preferable packages. In fact, it is a set of
diff --git a/compiler/rename/RnNames.hs b/compiler/rename/RnNames.hs
index 258e5ad231..fb5b29f876 100644
--- a/compiler/rename/RnNames.hs
+++ b/compiler/rename/RnNames.hs
@@ -897,6 +897,9 @@ filterImports iface decl_spec (Just (want_hiding, L l import_items))
     all_avails = mi_exports iface
 
         -- See Note [Dealing with imports]
+    -- If you remove the bang here then `imp_occ_env` gets computed
+    -- multiple times. (I think, it fixes a problem to do with GCing
+    -- FastString at least)
     imp_occ_env :: OccEnv (Name,    -- the name
                            AvailInfo,   -- the export item providing the name
                            Maybe Name)  -- the parent of associated types
@@ -923,7 +926,8 @@ filterImports iface decl_spec (Just (want_hiding, L l import_items))
        | Just succ <- mb_success = return succ
        | otherwise               = failLookupWith (BadImport ie)
       where
-        mb_success = lookupOccEnv imp_occ_env (rdrNameOcc rdr)
+        mb_success = do
+          lookupOccEnv imp_occ_env (rdrNameOcc rdr)
 
     lookup_lie :: LIE GhcPs -> TcRn [(LIE GhcRn, AvailInfo)]
     lookup_lie (L loc ieRdr)
diff --git a/compiler/typecheck/TcRnDriver.hs b/compiler/typecheck/TcRnDriver.hs
index 487ab1cb3d..660b3bfb1d 100644
--- a/compiler/typecheck/TcRnDriver.hs
+++ b/compiler/typecheck/TcRnDriver.hs
@@ -2746,7 +2746,7 @@ pprTcGblEnv (TcGblEnv { tcg_type_env  = type_env,
          , ppr_fam_insts fam_insts
          , ppr_rules rules
          , text "Dependent modules:" <+>
-                pprUniqMap ppr (imp_dep_mods imports) 
+                pprUniqMap ppr (imp_dep_mods imports)
          , text "Dependent packages:" <+>
                 ppr (S.toList $ imp_dep_pkgs imports)]
   where         -- The use of sort is just to reduce unnecessary
diff --git a/compiler/utils/FastString.hs b/compiler/utils/FastString.hs
index 2ea0d0ab13..af825ec26b 100644
--- a/compiler/utils/FastString.hs
+++ b/compiler/utils/FastString.hs
@@ -120,11 +120,8 @@ import GHC.Exts
 import System.IO
 import Data.Data
 import Data.IORef
-import Data.Maybe       ( isJust )
 import Data.Char
-import Data.List (deleteBy)
 import Data.Semigroup as Semi
-import Debug.Trace
 
 import System.Mem.Weak
 
@@ -137,7 +134,6 @@ import GHC.Conc.Sync    (sharedCAF)
 #endif
 
 import GHC.Base         ( unpackCString#, unpackNBytes# )
-import Debug.Trace
 import GHC.ForeignPtr
 import GHC.Weak
 
@@ -201,10 +197,13 @@ newtype FastString = FastString {
       fs_bs   :: ByteString
   }
 
+
+-- It is sufficient to test pointer equality as we guarantee that
+-- each string is uniquely allocated.
 instance Eq FastString where
   f1 == f2  =
     case (fs_bs f1, fs_bs f2) of
-      ((BS.PS fp i len), (BS.PS fp' i' len1)) -> fp == fp' && i == i'
+      ((BS.PS fp i _len), (BS.PS fp' i' _len1)) -> fp == fp' && i == i'
   {-# NOINLINE (==) #-}
 
 instance Ord FastString where
@@ -436,8 +435,7 @@ mkFastStringWith mk_fs !ptr !len = do
       !new_fs <- mk_fs
       withMVar lock $ \_ -> insert new_fs
   where
-    !(FastStringTable uid segments#) = stringTable
-    get_uid = atomicModifyIORef' uid $ \n -> (n+1,n)
+    !(FastStringTable _uid segments#) = stringTable
 
     !(I# hash#) = hashStr ptr len
     (# segmentRef #) = indexArray# segments# (hashToSegment# hash#)
@@ -458,10 +456,9 @@ mkFastStringWith mk_fs !ptr !len = do
                (# s1, w #) -> (# s1, Weak w #)
 --          v <- mkWeak fptr fs (Just $ atomicModifyIORef' fastStringGcCounter (\x -> (x +1, ())))
           IO $ \s1# ->
-            case writeArray# buckets# idx# (Left fs: bucket) s1# of
+            case writeArray# buckets# idx# (Right v: bucket) s1# of
               s2# -> (# s2#, () #)
           modifyIORef' counter succ
-          let u = uniqueOfFS fs
           return fs
           {-
     delete_fs :: Int -> IO ()
diff --git a/compiler/utils/FastStringEnv.hs b/compiler/utils/FastStringEnv.hs
index 909b58e201..f02a002152 100644
--- a/compiler/utils/FastStringEnv.hs
+++ b/compiler/utils/FastStringEnv.hs
@@ -125,18 +125,18 @@ emptyDFsEnv = emptyUDFM
 dFsEnvElts :: DFastStringEnv a -> [a]
 dFsEnvElts = map snd . eltsUDFM
 
-addToDFsEnv :: 
+addToDFsEnv ::
   HasFastString f => DFastStringEnv a -> f -> a -> DFastStringEnv a
 addToDFsEnv m f a = addToUDFM m (FastStringU $ getFastString f) (getFastString f, a)
 
-addListToDFsEnv :: 
+addListToDFsEnv ::
   HasFastString f => DFastStringEnv a -> [(f,a)] -> DFastStringEnv a
-addListToDFsEnv m fs = 
+addListToDFsEnv m fs =
     addListToUDFM m (map (\(f,a) -> ((FastStringU $ getFastString f), (getFastString f, a))) fs)
 
 
 mkDFsEnv :: HasFastString f => [(f,a)] -> DFastStringEnv a
-mkDFsEnv l = listToUDFM 
+mkDFsEnv l = listToUDFM
   (map (\(f, x) -> (FastStringU (getFastString f), (getFastString f, x))) l)
 
 lookupDFsEnv :: HasFastString f => DFastStringEnv a -> f -> Maybe a