Minor refactor around FastStringswip/strings-refactor3

Pass FastStrings to functions directly, to make sure the rule
for fsLit "literal" fires.

Remove SDoc indirection in GHCi.UI.Tags and GHC.Unit.Module.Graph.

36 files changed, 102 insertions, 95 deletions

diff --git a/compiler/GHC/Cmm/BlockId.hs b/compiler/GHC/Cmm/BlockId.hs
index e6396c8e83..ec52a3842a 100644
--- a/compiler/GHC/Cmm/BlockId.hs
+++ b/compiler/GHC/Cmm/BlockId.hs
@@ -11,6 +11,7 @@ module GHC.Cmm.BlockId
 import GHC.Prelude
 
 import GHC.Cmm.CLabel
+import GHC.Data.FastString
 import GHC.Types.Id.Info
 import GHC.Types.Name
 import GHC.Types.Unique
@@ -43,4 +44,4 @@ blockLbl label = mkLocalBlockLabel (getUnique label)
 
 infoTblLbl :: BlockId -> CLabel
 infoTblLbl label
-  = mkBlockInfoTableLabel (mkFCallName (getUnique label) "block") NoCafRefs
+  = mkBlockInfoTableLabel (mkFCallName (getUnique label) (fsLit "block")) NoCafRefs
diff --git a/compiler/GHC/Cmm/CLabel.hs b/compiler/GHC/Cmm/CLabel.hs
index bf4214fed2..22c1c9ef05 100644
--- a/compiler/GHC/Cmm/CLabel.hs
+++ b/compiler/GHC/Cmm/CLabel.hs
@@ -300,19 +300,19 @@ instance Show CLabel where
   show = showPprUnsafe . pprDebugCLabel genericPlatform
 
 data ModuleLabelKind
-    = MLK_Initializer String
+    = MLK_Initializer LexicalFastString
     | MLK_InitializerArray
-    | MLK_Finalizer String
+    | MLK_Finalizer LexicalFastString
     | MLK_FinalizerArray
     | MLK_IPEBuffer
     deriving (Eq, Ord)
 
 instance Outputable ModuleLabelKind where
-    ppr MLK_InitializerArray = text "init_arr"
-    ppr (MLK_Initializer s)  = text ("init__" ++ s)
-    ppr MLK_FinalizerArray   = text "fini_arr"
-    ppr (MLK_Finalizer s)    = text ("fini__" ++ s)
-    ppr MLK_IPEBuffer        = text "ipe_buf"
+    ppr MLK_InitializerArray                    = text "init_arr"
+    ppr (MLK_Initializer (LexicalFastString s)) = text "init__" <> ftext s
+    ppr MLK_FinalizerArray                      = text "fini_arr"
+    ppr (MLK_Finalizer (LexicalFastString s))   = text "fini__" <> ftext s
+    ppr MLK_IPEBuffer                           = text "ipe_buf"
 
 isIdLabel :: CLabel -> Bool
 isIdLabel IdLabel{} = True
@@ -885,15 +885,15 @@ mkDeadStripPreventer lbl        = DeadStripPreventer lbl
 mkStringLitLabel :: Unique -> CLabel
 mkStringLitLabel                = StringLitLabel
 
-mkInitializerStubLabel :: Module -> String -> CLabel
-mkInitializerStubLabel mod s    = ModuleLabel mod (MLK_Initializer s)
+mkInitializerStubLabel :: Module -> FastString -> CLabel
+mkInitializerStubLabel mod s    = ModuleLabel mod (MLK_Initializer (LexicalFastString s))
 
 mkInitializerArrayLabel :: Module -> CLabel
 mkInitializerArrayLabel mod     = ModuleLabel mod MLK_InitializerArray
 
 
-mkFinalizerStubLabel :: Module -> String -> CLabel
-mkFinalizerStubLabel mod s      = ModuleLabel mod (MLK_Finalizer s)
+mkFinalizerStubLabel :: Module -> FastString -> CLabel
+mkFinalizerStubLabel mod s      = ModuleLabel mod (MLK_Finalizer (LexicalFastString s))
 
 mkFinalizerArrayLabel :: Module -> CLabel
 mkFinalizerArrayLabel mod       = ModuleLabel mod MLK_FinalizerArray
diff --git a/compiler/GHC/CmmToAsm/AArch64/Ppr.hs b/compiler/GHC/CmmToAsm/AArch64/Ppr.hs
index 5ca443f08e..54cf73d55e 100644
--- a/compiler/GHC/CmmToAsm/AArch64/Ppr.hs
+++ b/compiler/GHC/CmmToAsm/AArch64/Ppr.hs
@@ -232,7 +232,7 @@ pprImm _ (ImmInt i)     = int i
 pprImm _ (ImmInteger i) = integer i
 pprImm p (ImmCLbl l)    = pprAsmLabel p l
 pprImm p (ImmIndex l i) = pprAsmLabel p l <> char '+' <> int i
-pprImm _ (ImmLit s)     = text s
+pprImm _ (ImmLit s)     = ftext s
 
 -- TODO: See pprIm below for why this is a bad idea!
 pprImm _ (ImmFloat f)
diff --git a/compiler/GHC/CmmToAsm/AArch64/Regs.hs b/compiler/GHC/CmmToAsm/AArch64/Regs.hs
index d3650c96f0..4895d2b092 100644
--- a/compiler/GHC/CmmToAsm/AArch64/Regs.hs
+++ b/compiler/GHC/CmmToAsm/AArch64/Regs.hs
@@ -2,6 +2,7 @@
 module GHC.CmmToAsm.AArch64.Regs where
 
 import GHC.Prelude
+import GHC.Data.FastString
 
 import GHC.Platform.Reg
 import GHC.Platform.Reg.Class
@@ -59,7 +60,7 @@ data Imm
   = ImmInt      Int
   | ImmInteger  Integer     -- Sigh.
   | ImmCLbl     CLabel      -- AbstractC Label (with baggage)
-  | ImmLit      String
+  | ImmLit      FastString
   | ImmIndex    CLabel Int
   | ImmFloat    Rational
   | ImmDouble   Rational
@@ -67,7 +68,7 @@ data Imm
   | ImmConstantDiff Imm Imm
   deriving (Eq, Show)
 
-strImmLit :: String -> Imm
+strImmLit :: FastString -> Imm
 strImmLit s = ImmLit s
 
 
diff --git a/compiler/GHC/CmmToAsm/PPC/CodeGen.hs b/compiler/GHC/CmmToAsm/PPC/CodeGen.hs
index f8563004b5..abad5d0427 100644
--- a/compiler/GHC/CmmToAsm/PPC/CodeGen.hs
+++ b/compiler/GHC/CmmToAsm/PPC/CodeGen.hs
@@ -407,7 +407,7 @@ getRegister' :: NCGConfig -> Platform -> CmmExpr -> NatM Register
 getRegister' _ platform (CmmReg (CmmGlobal PicBaseReg))
   | OSAIX <- platformOS platform = do
         let code dst = toOL [ LD II32 dst tocAddr ]
-            tocAddr = AddrRegImm toc (ImmLit "ghc_toc_table[TC]")
+            tocAddr = AddrRegImm toc (ImmLit (fsLit "ghc_toc_table[TC]"))
         return (Any II32 code)
   | target32Bit platform = do
       reg <- getPicBaseNat $ archWordFormat (target32Bit platform)
diff --git a/compiler/GHC/CmmToAsm/PPC/Ppr.hs b/compiler/GHC/CmmToAsm/PPC/Ppr.hs
index 19de3cd1e2..78abfcb0a3 100644
--- a/compiler/GHC/CmmToAsm/PPC/Ppr.hs
+++ b/compiler/GHC/CmmToAsm/PPC/Ppr.hs
@@ -240,7 +240,7 @@ pprImm platform = \case
    ImmInteger i   -> integer i
    ImmCLbl l      -> pprAsmLabel platform l
    ImmIndex l i   -> pprAsmLabel platform l <> char '+' <> int i
-   ImmLit s       -> text s
+   ImmLit s       -> ftext s
    ImmFloat f     -> float $ fromRational f
    ImmDouble d    -> double $ fromRational d
    ImmConstantSum a b   -> pprImm platform a <> char '+' <> pprImm platform b
diff --git a/compiler/GHC/CmmToAsm/PPC/Regs.hs b/compiler/GHC/CmmToAsm/PPC/Regs.hs
index 901913f7d9..5b4e179f1a 100644
--- a/compiler/GHC/CmmToAsm/PPC/Regs.hs
+++ b/compiler/GHC/CmmToAsm/PPC/Regs.hs
@@ -47,6 +47,7 @@ module GHC.CmmToAsm.PPC.Regs (
 where
 
 import GHC.Prelude
+import GHC.Data.FastString
 
 import GHC.Platform.Reg
 import GHC.Platform.Reg.Class
@@ -133,7 +134,7 @@ data Imm
         = ImmInt        Int
         | ImmInteger    Integer     -- Sigh.
         | ImmCLbl       CLabel      -- AbstractC Label (with baggage)
-        | ImmLit        String
+        | ImmLit        FastString
         | ImmIndex    CLabel Int
         | ImmFloat      Rational
         | ImmDouble     Rational
@@ -146,7 +147,7 @@ data Imm
         | HIGHESTA Imm
 
 
-strImmLit :: String -> Imm
+strImmLit :: FastString -> Imm
 strImmLit s = ImmLit s
 
 
diff --git a/compiler/GHC/CmmToAsm/X86/Instr.hs b/compiler/GHC/CmmToAsm/X86/Instr.hs
index 42b9543204..06fc3f6c7e 100644
--- a/compiler/GHC/CmmToAsm/X86/Instr.hs
+++ b/compiler/GHC/CmmToAsm/X86/Instr.hs
@@ -38,6 +38,7 @@ module GHC.CmmToAsm.X86.Instr
 where
 
 import GHC.Prelude
+import GHC.Data.FastString
 
 import GHC.CmmToAsm.X86.Cond
 import GHC.CmmToAsm.X86.Regs
@@ -868,7 +869,7 @@ mkStackAllocInstr platform amount
         case platformArch platform of
             ArchX86    | needs_probe_call platform amount ->
                            [ MOV II32 (OpImm (ImmInt amount)) (OpReg eax)
-                           , CALL (Left $ strImmLit "___chkstk_ms") [eax]
+                           , CALL (Left $ strImmLit (fsLit "___chkstk_ms")) [eax]
                            , SUB II32 (OpReg eax) (OpReg esp)
                            ]
                        | otherwise ->
@@ -877,7 +878,7 @@ mkStackAllocInstr platform amount
                            ]
             ArchX86_64 | needs_probe_call platform amount ->
                            [ MOV II64 (OpImm (ImmInt amount)) (OpReg rax)
-                           , CALL (Left $ strImmLit "___chkstk_ms") [rax]
+                           , CALL (Left $ strImmLit (fsLit "___chkstk_ms")) [rax]
                            , SUB II64 (OpReg rax) (OpReg rsp)
                            ]
                        | otherwise ->
diff --git a/compiler/GHC/CmmToAsm/X86/Ppr.hs b/compiler/GHC/CmmToAsm/X86/Ppr.hs
index 6c16160ce8..32b163357d 100644
--- a/compiler/GHC/CmmToAsm/X86/Ppr.hs
+++ b/compiler/GHC/CmmToAsm/X86/Ppr.hs
@@ -432,7 +432,7 @@ pprImm platform = \case
    ImmInteger i        -> integer i
    ImmCLbl l           -> pprAsmLabel platform l
    ImmIndex l i        -> pprAsmLabel platform l <> char '+' <> int i
-   ImmLit s            -> text s
+   ImmLit s            -> ftext s
    ImmFloat f          -> float $ fromRational f
    ImmDouble d         -> double $ fromRational d
    ImmConstantSum a b  -> pprImm platform a <> char '+' <> pprImm platform b
diff --git a/compiler/GHC/CmmToAsm/X86/Regs.hs b/compiler/GHC/CmmToAsm/X86/Regs.hs
index ab5558d8e1..25746f9deb 100644
--- a/compiler/GHC/CmmToAsm/X86/Regs.hs
+++ b/compiler/GHC/CmmToAsm/X86/Regs.hs
@@ -48,6 +48,7 @@ module GHC.CmmToAsm.X86.Regs (
 where
 
 import GHC.Prelude
+import GHC.Data.FastString
 
 import GHC.Platform.Regs
 import GHC.Platform.Reg
@@ -110,14 +111,14 @@ data Imm
   = ImmInt      Int
   | ImmInteger  Integer     -- Sigh.
   | ImmCLbl     CLabel      -- AbstractC Label (with baggage)
-  | ImmLit      String
+  | ImmLit      FastString
   | ImmIndex    CLabel Int
   | ImmFloat    Rational
   | ImmDouble   Rational
   | ImmConstantSum Imm Imm
   | ImmConstantDiff Imm Imm
 
-strImmLit :: String -> Imm
+strImmLit :: FastString -> Imm
 strImmLit s = ImmLit s
 
 
diff --git a/compiler/GHC/CmmToLlvm.hs b/compiler/GHC/CmmToLlvm.hs
index 5f585ef866..ea5884405e 100644
--- a/compiler/GHC/CmmToLlvm.hs
+++ b/compiler/GHC/CmmToLlvm.hs
@@ -110,8 +110,8 @@ llvmCodeGen' cfg cmm_stream
     header =
       let target  = llvmCgLlvmTarget cfg
           llvmCfg = llvmCgLlvmConfig cfg
-      in     text ("target datalayout = \"" ++ getDataLayout llvmCfg target ++ "\"")
-         $+$ text ("target triple = \"" ++ target ++ "\"")
+      in     (text "target datalayout = \"" <> text (getDataLayout llvmCfg target) <> text "\"")
+         $+$ (text "target triple = \"" <> text target <> text "\"")
 
     getDataLayout :: LlvmConfig -> String -> String
     getDataLayout config target =
diff --git a/compiler/GHC/Core/Coercion.hs b/compiler/GHC/Core/Coercion.hs
index 06bc235913..1449e2331d 100644
--- a/compiler/GHC/Core/Coercion.hs
+++ b/compiler/GHC/Core/Coercion.hs
@@ -146,6 +146,7 @@ import GHC.Types.Var.Set
 import GHC.Types.Name hiding ( varName )
 import GHC.Types.Basic
 import GHC.Types.Unique
+import GHC.Data.FastString
 import GHC.Data.Pair
 import GHC.Types.SrcLoc
 import GHC.Builtin.Names
@@ -286,7 +287,7 @@ tidyCoAxBndrsForUser init_env tcvs
         (env', bndr') = tidyVarBndr env bndr
         env_wild = (occ_env, extendVarEnv subst bndr wild_bndr)
         wild_bndr = setVarName bndr $
-                    tidyNameOcc (varName bndr) (mkTyVarOcc "_")
+                    tidyNameOcc (varName bndr) (mkTyVarOccFS (fsLit "_"))
                     -- Tidy the binder to "_"
 
     is_wildcard :: Var -> Bool
diff --git a/compiler/GHC/Core/FamInstEnv.hs b/compiler/GHC/Core/FamInstEnv.hs
index 844f753957..e955e5befd 100644
--- a/compiler/GHC/Core/FamInstEnv.hs
+++ b/compiler/GHC/Core/FamInstEnv.hs
@@ -50,6 +50,7 @@ import GHC.Core.RoughMap
 import GHC.Types.Var.Set
 import GHC.Types.Var.Env
 import GHC.Types.Name
+import GHC.Data.FastString
 import GHC.Data.Maybe
 import GHC.Types.Var
 import GHC.Types.SrcLoc
@@ -686,7 +687,7 @@ mkCoAxBranch tvs eta_tvs cvs lhs rhs roles loc
     -- See Note [Tidy axioms when we build them]
     -- See also Note [CoAxBranch type variables] in GHC.Core.Coercion.Axiom
 
-    init_occ_env = initTidyOccEnv [mkTyVarOcc "_"]
+    init_occ_env = initTidyOccEnv [mkTyVarOccFS (fsLit "_")]
     init_tidy_env = mkEmptyTidyEnv init_occ_env
     -- See Note [Always number wildcard types in CoAxBranch]
 
diff --git a/compiler/GHC/Core/TyCo/Tidy.hs b/compiler/GHC/Core/TyCo/Tidy.hs
index 36f1bb015a..2cbebbd411 100644
--- a/compiler/GHC/Core/TyCo/Tidy.hs
+++ b/compiler/GHC/Core/TyCo/Tidy.hs
@@ -17,6 +17,7 @@ module GHC.Core.TyCo.Tidy
   ) where
 
 import GHC.Prelude
+import GHC.Data.FastString
 
 import GHC.Core.TyCo.Rep
 import GHC.Core.TyCo.FVs (tyCoVarsOfTypesWellScoped, tyCoVarsOfTypeList)
@@ -70,7 +71,7 @@ getHelpfulOccName :: TyCoVar -> OccName
 -- this way is a helpful clue for users
 getHelpfulOccName tv
   | isSystemName name, isTcTyVar tv
-  = mkTyVarOcc (occNameString occ ++ "0")
+  = mkTyVarOccFS (occNameFS occ `appendFS` fsLit "0")
   | otherwise
   = occ
   where
diff --git a/compiler/GHC/Driver/CodeOutput.hs b/compiler/GHC/Driver/CodeOutput.hs
index 448c4c864e..2e56336cba 100644
--- a/compiler/GHC/Driver/CodeOutput.hs
+++ b/compiler/GHC/Driver/CodeOutput.hs
@@ -17,6 +17,7 @@ where
 import GHC.Prelude
 import GHC.Platform
 import GHC.ForeignSrcLang
+import GHC.Data.FastString
 
 import GHC.CmmToAsm     ( nativeCodeGen )
 import GHC.CmmToLlvm    ( llvmCodeGen )
@@ -331,7 +332,7 @@ profilingInitCode platform this_mod (local_CCs, singleton_CCSs)
    initializerCStub platform fn_name decls body
  where
    pdocC = pprCLabel platform
-   fn_name = mkInitializerStubLabel this_mod "prof_init"
+   fn_name = mkInitializerStubLabel this_mod (fsLit "prof_init")
    decls = vcat
         $  map emit_cc_decl local_CCs
         ++ map emit_ccs_decl singleton_CCSs
@@ -374,7 +375,7 @@ ipInitCode do_info_table platform this_mod
   | not do_info_table = mempty
   | otherwise = initializerCStub platform fn_nm ipe_buffer_decl body
  where
-   fn_nm = mkInitializerStubLabel this_mod "ip_init"
+   fn_nm = mkInitializerStubLabel this_mod (fsLit "ip_init")
 
    body = text "registerInfoProvList" <> parens (text "&" <> ipe_buffer_label) <> semi
 
diff --git a/compiler/GHC/HsToCore/Coverage.hs b/compiler/GHC/HsToCore/Coverage.hs
index 9e2619db65..146a1a2125 100644
--- a/compiler/GHC/HsToCore/Coverage.hs
+++ b/compiler/GHC/HsToCore/Coverage.hs
@@ -116,7 +116,7 @@ hpcInitCode _ _ (NoHpcInfo {}) = mempty
 hpcInitCode platform this_mod (HpcInfo tickCount hashNo)
  = initializerCStub platform fn_name decls body
   where
-    fn_name = mkInitializerStubLabel this_mod "hpc"
+    fn_name = mkInitializerStubLabel this_mod (fsLit "hpc")
     decls = text "extern StgWord64 " <> tickboxes <> text "[]" <> semi
     body = text "hs_hpc_module" <>
               parens (hcat (punctuate comma [
diff --git a/compiler/GHC/HsToCore/Foreign/Decl.hs b/compiler/GHC/HsToCore/Foreign/Decl.hs
index 60212b0d23..8257fea3bb 100644
--- a/compiler/GHC/HsToCore/Foreign/Decl.hs
+++ b/compiler/GHC/HsToCore/Foreign/Decl.hs
@@ -16,6 +16,7 @@ module GHC.HsToCore.Foreign.Decl
 where
 
 import GHC.Prelude
+import GHC.Data.FastString
 
 import GHC.Tc.Utils.Monad        -- temp
 
@@ -184,7 +185,7 @@ foreignExportsInitialiser platform mod hs_fns =
    -- See Note [Tracking foreign exports] in rts/ForeignExports.c
    initializerCStub platform fn_nm list_decl fn_body
   where
-    fn_nm       = mkInitializerStubLabel mod "fexports"
+    fn_nm       = mkInitializerStubLabel mod (fsLit "fexports")
     mod_str     = pprModuleName (moduleName mod)
     fn_body     = text "registerForeignExports" <> parens (char '&' <> list_symbol) <> semi
     list_symbol = text "stg_exports_" <> mod_str
diff --git a/compiler/GHC/Iface/Recomp.hs b/compiler/GHC/Iface/Recomp.hs
index 896f32df0a..db923a0982 100644
--- a/compiler/GHC/Iface/Recomp.hs
+++ b/compiler/GHC/Iface/Recomp.hs
@@ -19,6 +19,7 @@ module GHC.Iface.Recomp
 where
 
 import GHC.Prelude
+import GHC.Data.FastString
 
 import GHC.Driver.Backend
 import GHC.Driver.Config.Finder
@@ -168,7 +169,7 @@ instance Monoid RecompileRequired where
 
 data RecompReason
   = UnitDepRemoved UnitId
-  | ModulePackageChanged String
+  | ModulePackageChanged FastString
   | SourceFileChanged
   | ThisUnitIdChanged
   | ImpurePlugin
@@ -200,7 +201,7 @@ data RecompReason
 instance Outputable RecompReason where
   ppr = \case
     UnitDepRemoved uid       -> ppr uid <+> text "removed"
-    ModulePackageChanged s   -> text s <+> text "package changed"
+    ModulePackageChanged s   -> ftext s <+> text "package changed"
     SourceFileChanged        -> text "Source file changed"
     ThisUnitIdChanged        -> text "-this-unit-id changed"
     ImpurePlugin             -> text "Impure plugin forced recompilation"
@@ -596,7 +597,7 @@ checkDependencies hsc_env summary iface
                       -> [(t, GenLocated l ModuleName)]
                     -> IfG
                        [Either
-                          CompileReason (Either (UnitId, ModuleName) (String, UnitId))]
+                          CompileReason (Either (UnitId, ModuleName) (FastString, UnitId))]
    classify_import find_import imports =
     liftIO $ traverse (\(mb_pkg, L _ mod) ->
            let reason = ModuleChanged mod
@@ -612,9 +613,9 @@ checkDependencies hsc_env summary iface
    prev_dep_mods = map (second gwib_mod) $ Set.toAscList $ dep_direct_mods (mi_deps iface)
    prev_dep_pkgs = Set.toAscList (Set.union (dep_direct_pkgs (mi_deps iface))
                                             (dep_plugin_pkgs (mi_deps iface)))
-   bkpk_units    = map (("Signature",) . instUnitInstanceOf . moduleUnit) (requirementMerges units (moduleName (mi_module iface)))
+   bkpk_units    = map ((fsLit "Signature",) . instUnitInstanceOf . moduleUnit) (requirementMerges units (moduleName (mi_module iface)))
 
-   implicit_deps = map ("Implicit",) (implicitPackageDeps dflags)
+   implicit_deps = map (fsLit "Implicit",) (implicitPackageDeps dflags)
 
    -- GHC.Prim is very special and doesn't appear in ms_textual_imps but
    -- ghc-prim will appear in the package dependencies still. In order to not confuse
@@ -623,12 +624,12 @@ checkDependencies hsc_env summary iface
                               Just home_unit
                                 | homeUnitId home_unit == primUnitId
                                 -> Left (primUnitId, mkModuleName "GHC.Prim")
-                              _ -> Right ("GHC.Prim", primUnitId)
+                              _ -> Right (fsLit "GHC.Prim", primUnitId)
 
 
    classify _ (Found _ mod)
     | (toUnitId $ moduleUnit mod) `elem` all_home_units = Right (Left ((toUnitId $ moduleUnit mod), moduleName mod))
-    | otherwise = Right (Right (moduleNameString (moduleName mod), toUnitId $ moduleUnit mod))
+    | otherwise = Right (Right (moduleNameFS (moduleName mod), toUnitId $ moduleUnit mod))
    classify reason _ = Left (RecompBecause reason)
 
    check_mods :: [(UnitId, ModuleName)] -> [(UnitId, ModuleName)] -> IO RecompileRequired
@@ -649,7 +650,7 @@ checkDependencies hsc_env summary iface
            text " not among previous dependencies"
         return $ needsRecompileBecause $ ModuleAdded new
 
-   check_packages :: [(String, UnitId)] -> [UnitId] -> IO RecompileRequired
+   check_packages :: [(FastString, UnitId)] -> [UnitId] -> IO RecompileRequired
    check_packages [] [] = return UpToDate
    check_packages [] (old:_) = do
      trace_hi_diffs logger $
@@ -661,7 +662,7 @@ checkDependencies hsc_env summary iface
     , new_unit == old = check_packages (dropWhile ((== new_unit) . snd) news) olds'
     | otherwise = do
         trace_hi_diffs logger $
-         text "imported package" <+> text new_name <+> ppr new_unit <+>
+         text "imported package" <+> ftext new_name <+> ppr new_unit <+>
            text "not among previous dependencies"
         return $ needsRecompileBecause $ ModulePackageChanged new_name
 
@@ -1243,7 +1244,7 @@ addFingerprints hsc_env iface0
    iface_hash <- computeFingerprint putNameLiterally
                       (mod_hash,
                        mi_src_hash iface0,
-                       ann_fn (mkVarOcc "module"),  -- See mkIfaceAnnCache
+                       ann_fn (mkVarOccFS (fsLit "module")),  -- See mkIfaceAnnCache
                        mi_usages iface0,
                        sorted_deps,
                        mi_hpc iface0)
@@ -1638,7 +1639,7 @@ mkIfaceAnnCache anns
     pair (IfaceAnnotation target value) =
       (case target of
           NamedTarget occn -> occn
-          ModuleTarget _   -> mkVarOcc "module"
+          ModuleTarget _   -> mkVarOccFS (fsLit "module")
       , [value])
     -- flipping (++), so the first argument is always short
     env = mkOccEnv_C (flip (++)) (map pair anns)
diff --git a/compiler/GHC/Iface/Tidy/StaticPtrTable.hs b/compiler/GHC/Iface/Tidy/StaticPtrTable.hs
index cf37095041..d53fddb943 100644
--- a/compiler/GHC/Iface/Tidy/StaticPtrTable.hs
+++ b/compiler/GHC/Iface/Tidy/StaticPtrTable.hs
@@ -144,6 +144,7 @@ import GHC.Linker.Types
 import GHC.Types.Id
 import GHC.Types.ForeignStubs
 import GHC.Data.Maybe
+import GHC.Data.FastString
 
 import Control.Monad.Trans.State.Strict
 import Data.List (intercalate)
@@ -244,7 +245,7 @@ sptModuleInitCode platform this_mod entries =
     initializerCStub platform init_fn_nm empty init_fn_body `mappend`
     finalizerCStub platform fini_fn_nm empty fini_fn_body
   where
-    init_fn_nm = mkInitializerStubLabel this_mod "spt"
+    init_fn_nm = mkInitializerStubLabel this_mod (fsLit "spt")
     init_fn_body = vcat
         [  text "static StgWord64 k" <> int i <> text "[2] = "
            <> pprFingerprint fp <> semi
@@ -260,7 +261,7 @@ sptModuleInitCode platform this_mod entries =
         |  (i, SptEntry n fp) <- zip [0..] entries
         ]
 
-    fini_fn_nm = mkFinalizerStubLabel this_mod "spt"
+    fini_fn_nm = mkFinalizerStubLabel this_mod (fsLit "spt")
     fini_fn_body = vcat
         [  text "StgWord64 k" <> int i <> text "[2] = "
            <> pprFingerprint fp <> semi
diff --git a/compiler/GHC/Parser.y b/compiler/GHC/Parser.y
index 7b7ab4f4c8..cc2dcf2749 100644
--- a/compiler/GHC/Parser.y
+++ b/compiler/GHC/Parser.y
@@ -67,7 +67,7 @@ import GHC.Prelude
 import qualified GHC.Data.Strict as Strict
 
 import GHC.Types.Name.Reader
-import GHC.Types.Name.Occurrence ( varName, dataName, tcClsName, tvName, occNameFS, mkVarOccFS, occNameString)
+import GHC.Types.Name.Occurrence ( varName, dataName, tcClsName, tvName, occNameFS, mkVarOccFS)
 import GHC.Types.SrcLoc
 import GHC.Types.Basic
 import GHC.Types.Error ( GhcHint(..) )
@@ -3885,8 +3885,7 @@ modid   :: { LocatedA ModuleName }
         : CONID                 { sL1a $1 $ mkModuleNameFS (getCONID $1) }
         | QCONID                { sL1a $1 $ let (mod,c) = getQCONID $1 in
                                   mkModuleNameFS
-                                   (mkFastString
-                                     (unpackFS mod ++ '.':unpackFS c))
+                                   (concatFS [mod, fsLit ".", c])
                                 }
 
 commas :: { ([SrcSpan],Int) }   -- One or more commas
diff --git a/compiler/GHC/Parser/PostProcess.hs b/compiler/GHC/Parser/PostProcess.hs
index 8e08a8c874..2dd8e06b3e 100644
--- a/compiler/GHC/Parser/PostProcess.hs
+++ b/compiler/GHC/Parser/PostProcess.hs
@@ -1816,7 +1816,7 @@ instance DisambECP (HsExpr GhcPs) where
   rejectPragmaPV _                        = return ()
 
 hsHoleExpr :: EpAnn EpAnnUnboundVar -> HsExpr GhcPs
-hsHoleExpr anns = HsUnboundVar anns (mkVarOcc "_")
+hsHoleExpr anns = HsUnboundVar anns (mkVarOccFS (fsLit "_"))
 
 type instance Anno (GRHS GhcPs (LocatedA (PatBuilder GhcPs))) = SrcAnn NoEpAnns
 type instance Anno [LocatedA (Match GhcPs (LocatedA (PatBuilder GhcPs)))] = SrcSpanAnnL
diff --git a/compiler/GHC/Rename/Expr.hs b/compiler/GHC/Rename/Expr.hs
index 9e7decb2ff..4d22a994e9 100644
--- a/compiler/GHC/Rename/Expr.hs
+++ b/compiler/GHC/Rename/Expr.hs
@@ -28,6 +28,7 @@ module GHC.Rename.Expr (
    ) where
 
 import GHC.Prelude
+import GHC.Data.FastString
 
 import GHC.Rename.Bind ( rnLocalBindsAndThen, rnLocalValBindsLHS, rnLocalValBindsRHS
                         , rnMatchGroup, rnGRHS, makeMiniFixityEnv)
@@ -2692,7 +2693,7 @@ getMonadFailOp ctxt
       | (isQualifiedDo || rebindableSyntax) && overloadedStrings = do
         (failExpr, failFvs) <- lookupQualifiedDoExpr ctxt failMName
         (fromStringExpr, fromStringFvs) <- lookupSyntaxExpr fromStringName
-        let arg_lit = mkVarOcc "arg"
+        let arg_lit = mkVarOccFS (fsLit "arg")
         arg_name <- newSysName arg_lit
         let arg_syn_expr = nlHsVar arg_name
             body :: LHsExpr GhcRn =
diff --git a/compiler/GHC/Runtime/Eval.hs b/compiler/GHC/Runtime/Eval.hs
index 3acebb5894..75a6123891 100644
--- a/compiler/GHC/Runtime/Eval.hs
+++ b/compiler/GHC/Runtime/Eval.hs
@@ -1048,7 +1048,7 @@ parseInstanceHead str = withSession $ \hsc_env0 -> do
 -- Get all the constraints required of a dictionary binding
 getDictionaryBindings :: PredType -> TcM CtEvidence
 getDictionaryBindings theta = do
-  dictName <- newName (mkDictOcc (mkVarOcc "magic"))
+  dictName <- newName (mkDictOcc (mkVarOccFS (fsLit "magic")))
   let dict_var = mkVanillaGlobal dictName theta
   loc <- getCtLocM (GivenOrigin (getSkolemInfo unkSkol)) Nothing
 
diff --git a/compiler/GHC/Runtime/Loader.hs b/compiler/GHC/Runtime/Loader.hs
index 5189e5bec4..e578c25357 100644
--- a/compiler/GHC/Runtime/Loader.hs
+++ b/compiler/GHC/Runtime/Loader.hs
@@ -21,6 +21,7 @@ module GHC.Runtime.Loader (
     ) where
 
 import GHC.Prelude
+import GHC.Data.FastString
 
 import GHC.Driver.Session
 import GHC.Driver.Ppr
@@ -46,7 +47,7 @@ import GHC.Types.SrcLoc        ( noSrcSpan )
 import GHC.Types.Name    ( Name, nameModule_maybe )
 import GHC.Types.Id      ( idType )
 import GHC.Types.TyThing
-import GHC.Types.Name.Occurrence ( OccName, mkVarOcc )
+import GHC.Types.Name.Occurrence ( OccName, mkVarOccFS )
 import GHC.Types.Name.Reader   ( RdrName, ImportSpec(..), ImpDeclSpec(..)
                                , ImpItemSpec(..), mkGlobalRdrEnv, lookupGRE_RdrName
                                , greMangledName, mkRdrQual )
@@ -136,14 +137,14 @@ loadPlugins hsc_env
       where
         options = [ option | (opt_mod_nm, option) <- pluginModNameOpts dflags
                             , opt_mod_nm == mod_nm ]
-    loadPlugin = loadPlugin' (mkVarOcc "plugin") pluginTyConName hsc_env
+    loadPlugin = loadPlugin' (mkVarOccFS (fsLit "plugin")) pluginTyConName hsc_env
 
 
 loadFrontendPlugin :: HscEnv -> ModuleName -> IO (FrontendPlugin, [Linkable], PkgsLoaded)
 loadFrontendPlugin hsc_env mod_name = do
     checkExternalInterpreter hsc_env
     (plugin, _iface, links, pkgs)
-      <- loadPlugin' (mkVarOcc "frontendPlugin") frontendPluginTyConName
+      <- loadPlugin' (mkVarOccFS (fsLit "frontendPlugin")) frontendPluginTyConName
            hsc_env mod_name
     return (plugin, links, pkgs)
 
diff --git a/compiler/GHC/Tc/Errors/Hole.hs b/compiler/GHC/Tc/Errors/Hole.hs
index 8ec874da41..5590e29454 100644
--- a/compiler/GHC/Tc/Errors/Hole.hs
+++ b/compiler/GHC/Tc/Errors/Hole.hs
@@ -82,7 +82,7 @@ import GHC.Builtin.Utils (knownKeyNames)
 import GHC.Tc.Errors.Hole.FitTypes
 import qualified Data.Set as Set
 import GHC.Types.SrcLoc
-import GHC.Data.FastString (unpackFS)
+import GHC.Data.FastString (NonDetFastString(..))
 import GHC.Types.Unique.Map
 
 
@@ -482,15 +482,16 @@ addHoleFitDocs fits =
      Just m  -> Right m
      Nothing ->
        Left $ case nameSrcLoc name of
-         RealSrcLoc r _ -> unpackFS $ srcLocFile r
-         UnhelpfulLoc s -> unpackFS $ s
+         -- Nondeterminism is fine, this is used only to display a warning
+         RealSrcLoc r _ -> NonDetFastString $ srcLocFile r
+         UnhelpfulLoc s -> NonDetFastString s
    report mods = do
      { let warning =
              text "WARNING: Couldn't find any documentation for the following modules:" $+$
              nest 2
-                  (pprWithCommas (either text ppr) (Set.toList mods) $+$
+                  (pprWithCommas (either ppr ppr) (Set.toList mods) $+$
                    text "Make sure the modules are compiled with '-haddock'.")
-     ; warnPprTrace (not $ Set.null mods)"addHoleFitDocs" warning (pure ())
+     ; warnPprTrace (not $ Set.null mods) "addHoleFitDocs" warning (pure ())
      }
 
 -- For pretty printing hole fits, we display the name and type of the fit,
diff --git a/compiler/GHC/Tc/Gen/Sig.hs b/compiler/GHC/Tc/Gen/Sig.hs
index cfc5454e54..6b141d9173 100644
--- a/compiler/GHC/Tc/Gen/Sig.hs
+++ b/compiler/GHC/Tc/Gen/Sig.hs
@@ -26,6 +26,7 @@ module GHC.Tc.Gen.Sig(
    ) where
 
 import GHC.Prelude
+import GHC.Data.FastString
 
 import GHC.Driver.Session
 import GHC.Driver.Backend
@@ -246,7 +247,7 @@ tcUserTypeSig loc hs_sig_ty mb_name
   where
     name   = case mb_name of
                Just n  -> n
-               Nothing -> mkUnboundName (mkVarOcc "<expression>")
+               Nothing -> mkUnboundName (mkVarOccFS (fsLit "<expression>"))
 
     ctxt_rrc    = ctxt_fn (lhsSigWcTypeContextSpan hs_sig_ty)
     ctxt_no_rrc = ctxt_fn NoRRC
diff --git a/compiler/GHC/Tc/Instance/Typeable.hs b/compiler/GHC/Tc/Instance/Typeable.hs
index 3c5343722e..e0bcfa8428 100644
--- a/compiler/GHC/Tc/Instance/Typeable.hs
+++ b/compiler/GHC/Tc/Instance/Typeable.hs
@@ -190,7 +190,7 @@ mkModIdBindings :: TcM TcGblEnv
 mkModIdBindings
   = do { mod <- getModule
        ; loc <- getSrcSpanM
-       ; mod_nm        <- newGlobalBinder mod (mkVarOcc "$trModule") loc
+       ; mod_nm        <- newGlobalBinder mod (mkVarOccFS (fsLit "$trModule")) loc
        ; trModuleTyCon <- tcLookupTyCon trModuleTyConName
        ; let mod_id = mkExportedVanillaId mod_nm (mkTyConApp trModuleTyCon [])
        ; mod_bind      <- mkVarBind mod_id <$> mkModIdRHS mod
diff --git a/compiler/GHC/Tc/TyCl/PatSyn.hs b/compiler/GHC/Tc/TyCl/PatSyn.hs
index 2e9b3c1809..a448d550ac 100644
--- a/compiler/GHC/Tc/TyCl/PatSyn.hs
+++ b/compiler/GHC/Tc/TyCl/PatSyn.hs
@@ -787,8 +787,8 @@ tcPatSynMatcher (L loc ps_name) lpat prag_fn
                 (ex_tvs, ex_tys, prov_theta, prov_dicts)
                 (args, arg_tys) pat_ty
   = do { let loc' = locA loc
-       ; rr_name <- newNameAt (mkTyVarOcc "rep") loc'
-       ; tv_name <- newNameAt (mkTyVarOcc "r")   loc'
+       ; rr_name <- newNameAt (mkTyVarOccFS (fsLit "rep")) loc'
+       ; tv_name <- newNameAt (mkTyVarOccFS (fsLit "r"))   loc'
        ; let rr_tv  = mkTyVar rr_name runtimeRepTy
              rr     = mkTyVarTy rr_tv
              res_tv = mkTyVar tv_name (mkTYPEapp rr)
diff --git a/compiler/GHC/Tc/Utils/Monad.hs b/compiler/GHC/Tc/Utils/Monad.hs
index 8319212147..2f61ff8777 100644
--- a/compiler/GHC/Tc/Utils/Monad.hs
+++ b/compiler/GHC/Tc/Utils/Monad.hs
@@ -1921,7 +1921,7 @@ emitAnonTypeHole extra_constraints tv
                          , hole_loc  = ct_loc }
        ; emitHole hole }
   where
-    occ = mkTyVarOcc "_"
+    occ = mkTyVarOccFS (fsLit "_")
     sort | YesExtraConstraint <- extra_constraints = ConstraintHole
          | otherwise                               = TypeHole
 
diff --git a/compiler/GHC/Tc/Validity.hs b/compiler/GHC/Tc/Validity.hs
index 4dc4161664..97f9a8384f 100644
--- a/compiler/GHC/Tc/Validity.hs
+++ b/compiler/GHC/Tc/Validity.hs
@@ -21,6 +21,7 @@ module GHC.Tc.Validity (
   ) where
 
 import GHC.Prelude
+import GHC.Data.FastString
 
 import GHC.Data.Maybe
 
@@ -2274,7 +2275,7 @@ checkConsistentFamInst (InClsInst { ai_class = clas
                    tidyTypes tidy_env2 ax_arg_tys
 
     mk_wildcard at_tv = mkTyVarTy (mkTyVar tv_name (tyVarKind at_tv))
-    tv_name = mkInternalName (mkAlphaTyVarUnique 1) (mkTyVarOcc "_") noSrcSpan
+    tv_name = mkInternalName (mkAlphaTyVarUnique 1) (mkTyVarOccFS (fsLit "_")) noSrcSpan
 
     -- For check_match, bind_me, see
     -- Note [Matching in the consistent-instantiation check]
diff --git a/compiler/GHC/Types/Id/Make.hs b/compiler/GHC/Types/Id/Make.hs
index b38cde14a1..99ea5dddb0 100644
--- a/compiler/GHC/Types/Id/Make.hs
+++ b/compiler/GHC/Types/Id/Make.hs
@@ -1320,7 +1320,7 @@ mkFCallId uniq fcall ty
     -- The "occurrence name" of a ccall is the full info about the
     -- ccall; it is encoded, but may have embedded spaces etc!
 
-    name = mkFCallName uniq occ_str
+    name = mkFCallName uniq (mkFastString occ_str)
 
     info = noCafIdInfo
            `setArityInfo`  arity
diff --git a/compiler/GHC/Types/Name.hs b/compiler/GHC/Types/Name.hs
index 9f82fd42a8..8176bec011 100644
--- a/compiler/GHC/Types/Name.hs
+++ b/compiler/GHC/Types/Name.hs
@@ -493,8 +493,8 @@ mkSysTvName :: Unique -> FastString -> Name
 mkSysTvName uniq fs = mkSystemName uniq (mkTyVarOccFS fs)
 
 -- | Make a name for a foreign call
-mkFCallName :: Unique -> String -> Name
-mkFCallName uniq str = mkInternalName uniq (mkVarOcc str) noSrcSpan
+mkFCallName :: Unique -> FastString -> Name
+mkFCallName uniq str = mkInternalName uniq (mkVarOccFS str) noSrcSpan
    -- The encoded string completely describes the ccall
 
 -- When we renumber/rename things, we need to be
diff --git a/compiler/GHC/Unit/Module/Graph.hs b/compiler/GHC/Unit/Module/Graph.hs
index fcd6a63a28..c2d36c5c0e 100644
--- a/compiler/GHC/Unit/Module/Graph.hs
+++ b/compiler/GHC/Unit/Module/Graph.hs
@@ -49,7 +49,6 @@ import GHC.Data.Maybe
 import GHC.Data.Graph.Directed
 
 import GHC.Driver.Backend
-import GHC.Driver.Ppr
 import GHC.Driver.Session
 
 import GHC.Types.SourceFile ( hscSourceString )
@@ -278,8 +277,8 @@ showModMsg dflags recomp (ModuleNode _ mod_summary) =
 
   where
     op       = normalise
-    mod      = moduleName (ms_mod mod_summary)
-    mod_str  = showPpr dflags mod ++ hscSourceString (ms_hsc_src mod_summary)
+    mod_str  = moduleNameString (moduleName (ms_mod mod_summary)) ++
+               hscSourceString (ms_hsc_src mod_summary)
     dyn_file = op $ msDynObjFilePath mod_summary
     obj_file = op $ msObjFilePath mod_summary
     files    = [ obj_file ]
diff --git a/ghc/GHCi/UI.hs b/ghc/GHCi/UI.hs
index f697073763..3e1bc227d1 100644
--- a/ghc/GHCi/UI.hs
+++ b/ghc/GHCi/UI.hs
@@ -2554,7 +2554,7 @@ isSafeModule m = do
                                     (GHC.moduleNameString $ GHC.moduleName m))
 
     (msafe, pkgs) <- GHC.moduleTrustReqs m
-    let trust  = showPpr dflags $ getSafeMode $ GHC.mi_trust $ fromJust iface
+    let trust  = show $ getSafeMode $ GHC.mi_trust $ fromJust iface
         pkg    = if packageTrusted hsc_env m then "trusted" else "untrusted"
         (good, bad) = tallyPkgs hsc_env pkgs
 
@@ -2998,7 +2998,7 @@ showOptions show_all
                    then text "none."
                    else hsep (map (\o -> char '+' <> text (optToStr o)) opts)
            ))
-       getDynFlags >>= liftIO . showDynFlags show_all
+       liftIO $ showDynFlags show_all dflags
 
 
 showDynFlags :: Bool -> DynFlags -> IO ()
@@ -3215,9 +3215,9 @@ unsetOptions str
          no_flag ('-':'X':rest) = return ("-XNo" ++ rest)
          no_flag f = throwGhcException (ProgramError ("don't know how to reverse " ++ f))
 
-     in if (not (null rest3))
-           then liftIO (putStrLn ("unknown option: '" ++ head rest3 ++ "'"))
-           else do
+     in case rest3 of
+          opt:_ -> liftIO (putStrLn ("unknown option: '" ++ opt ++ "'"))
+          [] -> do
              mapM_ (fromJust.flip lookup defaulters) other_opts
 
              mapM_ unsetOpt plus_opts
diff --git a/ghc/GHCi/UI/Monad.hs b/ghc/GHCi/UI/Monad.hs
index aae605efa8..3e6b834e11 100644
--- a/ghc/GHCi/UI/Monad.hs
+++ b/ghc/GHCi/UI/Monad.hs
@@ -502,8 +502,8 @@ initInterpBuffering = do
       mkHelperExpr occ =
         GHC.compileParsedExprRemote
         $ GHC.nlHsVar $ RdrName.mkOrig gHC_GHCI_HELPERS occ
-  nobuf <- mkHelperExpr $ mkVarOcc "disableBuffering"
-  flush <- mkHelperExpr $ mkVarOcc "flushAll"
+  nobuf <- mkHelperExpr $ mkVarOccFS (fsLit "disableBuffering")
+  flush <- mkHelperExpr $ mkVarOccFS (fsLit "flushAll")
   return (nobuf, flush)
 
 -- | Invoke "hFlush stdout; hFlush stderr" in the interpreter
@@ -532,7 +532,7 @@ mkEvalWrapper progname' args' =
   where
     nlHsString = nlHsLit . mkHsString
     evalWrapper' =
-      GHC.nlHsVar $ RdrName.mkOrig gHC_GHCI_HELPERS (mkVarOcc "evalWrapper")
+      GHC.nlHsVar $ RdrName.mkOrig gHC_GHCI_HELPERS (mkVarOccFS (fsLit "evalWrapper"))
 
 -- | Run a 'GhcMonad' action to compile an expression for internal usage.
 runInternal :: GhcMonad m => m a -> m a
diff --git a/ghc/GHCi/UI/Tags.hs b/ghc/GHCi/UI/Tags.hs
index f1d55eab15..ebf2d5ebab 100644
--- a/ghc/GHCi/UI/Tags.hs
+++ b/ghc/GHCi/UI/Tags.hs
@@ -16,16 +16,14 @@ module GHCi.UI.Tags (
 import GHC.Utils.Exception
 import GHC
 import GHCi.UI.Monad
-import GHC.Utils.Outputable
 
 -- ToDo: figure out whether we need these, and put something appropriate
 -- into the GHC API instead
 import GHC.Types.Name (nameOccName)
-import GHC.Types.Name.Occurrence (pprOccName)
+import GHC.Types.Name.Occurrence (occNameString)
 import GHC.Core.ConLike
 import GHC.Utils.Monad
-import GHC.Unit.State
-import GHC.Driver.Env
+import GHC.Data.FastString
 
 import Control.Monad
 import Data.Function
@@ -34,7 +32,6 @@ import qualified Data.List.NonEmpty as NE
 import Data.Maybe
 import Data.Ord
 import GHC.Driver.Phases
-import GHC.Driver.Ppr
 import GHC.Utils.Panic
 import Prelude
 import System.Directory
@@ -97,14 +94,10 @@ listModuleTags m = do
   case mbModInfo of
     Nothing -> return []
     Just mInfo -> do
-       dflags <- getDynFlags
-       unit_state <- hsc_units <$> getSession
-       mb_print_unqual <- GHC.mkPrintUnqualifiedForModule mInfo
-       let unqual = fromMaybe GHC.alwaysQualify mb_print_unqual
        let names = fromMaybe [] $ GHC.modInfoTopLevelScope mInfo
        let localNames = filter ((m==) . nameModule) names
        mbTyThings <- mapM GHC.lookupName localNames
-       return $! [ tagInfo dflags unit_state unqual exported kind name realLoc
+       return $! [ tagInfo exported kind name realLoc
                      | tyThing <- catMaybes mbTyThings
                      , let name = getName tyThing
                      , let exported = GHC.modInfoIsExportedName mInfo name
@@ -133,13 +126,12 @@ data TagInfo = TagInfo
 
 
 -- get tag info, for later translation into Vim or Emacs style
-tagInfo :: DynFlags -> UnitState -> PrintUnqualified
-        -> Bool -> Char -> Name -> RealSrcLoc
+tagInfo :: Bool -> Char -> Name -> RealSrcLoc
         -> TagInfo
-tagInfo dflags unit_state unqual exported kind name loc
+tagInfo exported kind name loc
     = TagInfo exported kind
-        (showSDocForUser dflags unit_state unqual $ pprOccName (nameOccName name))
-        (showSDocForUser dflags unit_state unqual $ ftext (srcLocFile loc))
+        (occNameString $ nameOccName name)
+        (unpackFS (srcLocFile loc))
         (srcLocLine loc) (srcLocCol loc) Nothing
 
 -- throw an exception when someone tries to overwrite existing source file (fix for #10989)